From d1307ef1641508081146380d5006411c69f22528 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 4 Mar 2021 14:46:34 +0200
Subject: [PATCH 01/59] added T1 experiment

---
 qiskit_experiments/__init__.py                |   2 +
 qiskit_experiments/base_experiment.py         |  10 +-
 .../characterization/t1_experiment.py         | 129 ++++++++++++++++++
 test/test_t1.py                               |  68 +++++++++
 4 files changed, 204 insertions(+), 5 deletions(-)
 create mode 100644 qiskit_experiments/characterization/t1_experiment.py
 create mode 100644 test/test_t1.py

diff --git a/qiskit_experiments/__init__.py b/qiskit_experiments/__init__.py
index eb4560cf67..2ac660043c 100644
--- a/qiskit_experiments/__init__.py
+++ b/qiskit_experiments/__init__.py
@@ -19,3 +19,5 @@
 
 # Experiment modules
 from . import composite
+from . import characterization
+
diff --git a/qiskit_experiments/base_experiment.py b/qiskit_experiments/base_experiment.py
index aad92eeaad..5ec835599b 100644
--- a/qiskit_experiments/base_experiment.py
+++ b/qiskit_experiments/base_experiment.py
@@ -60,14 +60,14 @@ class BaseExperiment(ABC):
     __experiment_data__ = ExperimentData
 
     def __init__(self, qubits, experiment_type=None, circuit_options=None):
-        """Initialize the analysis object.
+        """Initialize the experiment object.
 
         Args:
             qubits (int or Iterable[int]): the number of qubits or list of
                                            physical qubits for the experiment.
             experiment_type (str): Optional, the experiment type string.
-            circuit_options (str): Optional, dictionary of allowed kwargs and
-                                   default values for the `circuit` method.
+            circuit_options (dict): Optional, dictionary of allowed kwargs and
+                                    default values for the `circuit` method.
 
         Raises:
             QiskitError: if qubits is a list and contains duplicates.
@@ -111,7 +111,7 @@ def run(self, backend, experiment_data=None, **kwargs):
 
         # Generate and run circuits
         circuits = self.transpiled_circuits(backend, **kwargs)
-        qobj = assemble(circuits)
+        qobj = assemble(circuits, backend)
         job = backend.run(qobj, **kwargs)
 
         # Add Job to ExperimentData
@@ -190,7 +190,7 @@ def transpiled_circuits(self, backend=None, **kwargs):
         circuit_options = {}
         transpile_options = {}
         for key in kwargs:
-            if key in self._circuit_options:
+            if self._circuit_options is not None and key in self._circuit_options:
                 circuit_options[key] = kwargs[key]
             elif key in _TRANSPILE_OPTIONS:
                 transpile_options[key] = kwargs[key]
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
new file mode 100644
index 0000000000..7876313c4c
--- /dev/null
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -0,0 +1,129 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""
+T1 Experiment class.
+"""
+
+from typing import List, Optional, Union, Tuple
+import numpy as np
+from scipy.optimize import curve_fit
+
+from qiskit.circuit import QuantumCircuit
+
+from qiskit_experiments.base_experiment import BaseExperiment
+from qiskit_experiments.base_analysis import BaseAnalysis
+from qiskit_experiments import AnalysisResult
+
+
+class T1Analysis(BaseAnalysis):
+    """T1 Experiment result analysis class."""
+
+    def _run_analysis(self, experiment_data, **params) -> Tuple[AnalysisResult, None]:
+        """
+        Calculate T1
+
+        Args:
+            experiment_data: the experiment data to analyze
+            params: expected parameters therein are:
+                   `fit_p0` and `fit_bounds` - to be passed to scipy.optimize.curve_fit
+                                               as the `p0` and `bounds` parameters
+
+        Returns:
+            The analysis result with the estimated T1
+        """
+
+        prob1 = {}
+        for circ in experiment_data._data:
+            delay = circ['metadata']['delay']
+            count0 = circ['counts'].get('0', 0)
+            count1 = circ['counts'].get('1', 0)
+            shots = count0 + count1
+            mean = count1 / shots
+            std = np.sqrt(mean * (1-mean) / shots)
+            # problem for the fitter if one of the std points is
+            # exactly zero
+            if std == 0:
+                std = 1e-4
+            prob1[delay] = (mean, std)
+
+        delays = []
+        means = []
+        stds = []
+        for delay in sorted(prob1):
+            delays.append(delay)
+            means.append(prob1[delay][0])
+            stds.append(prob1[delay][1])
+
+        def exp_fit_fun(x, a, tau, c):
+            return a * np.exp(-x / tau) + c
+
+        fit_out, _ = \
+            curve_fit(exp_fit_fun, delays, means, sigma=stds,
+                      p0=params['fit_p0'], bounds=params['fit_bounds'])
+
+        analysis_result = AnalysisResult({'value': fit_out[1]})
+        return analysis_result, None
+
+
+class T1Experiment(BaseExperiment):
+    """T1 experiment class"""
+
+    __analysis_class__ = T1Analysis
+
+    def __init__(self,
+                 qubit: int,
+                 delays: Union[List[float], np.array],
+                 unit: str = 'dt'):
+        """
+        Initialize the T1 experiment class
+
+        Args:
+            qubit: the qubit whose T1 is to be estimated
+            delays: delay times of the experiments
+            unit: time unit of `delays`
+        """
+        self._delays = delays
+        self._unit = unit
+        super().__init__([qubit], type(self).__name__)
+
+    def circuits(self, backend: Optional["Backend"] = None,
+                 **circuit_options) -> List[QuantumCircuit]:
+        """
+        Return a list of experiment circuits
+
+        Args:
+            backend: a backend object
+            circuit_options: kwarg options for the function
+
+        Returns:
+            The experiment circuits
+        """
+
+        circuits = []
+
+        for circ_index, delay in enumerate(self._delays):
+            circ = QuantumCircuit(1, 1)
+            circ.x(0)
+            circ.delay(delay, 0, self._unit)
+            circ.measure(0, 0)
+
+            # pylint: disable = eval-used
+            circ.metadata = {
+                'experiment_type': self._type,
+                'qubit': self.physical_qubits[0],
+                'delay': delay}
+
+            circuits.append(circ)
+
+        return circuits
diff --git a/test/test_t1.py b/test/test_t1.py
new file mode 100644
index 0000000000..2792dc8e33
--- /dev/null
+++ b/test/test_t1.py
@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""
+Test T1 experiment
+"""
+
+import unittest
+
+import numpy as np
+
+from qiskit.providers.aer import QasmSimulator
+from qiskit.providers.aer.noise.errors.standard_errors import thermal_relaxation_error
+from qiskit.providers.aer.noise import NoiseModel
+
+from qiskit_experiments.composite import BatchExperiment, ParallelExperiment
+from qiskit_experiments.characterization import T1Experiment
+
+backend = QasmSimulator()
+instruction_durations = \
+                      [('measure', [0], 3, 'dt'),
+                       ('x', [0], 3, 'dt')]
+gate_time = 0.1
+
+# Fix seed for simulations
+SEED = 9000
+
+class TestT1(unittest.TestCase):
+    """
+    Test measurement of T1
+    """
+
+    def test_t1(self):
+        """
+        Test T1 experiment using a simulator.
+        Currently only verifies that there is no exception,
+        but does not verify accuracy of the estimate.
+        """
+
+        t1 = 25
+
+        noise_model = NoiseModel()
+        noise_model.add_quantum_error(
+            thermal_relaxation_error(t1, 2*t1, gate_time),
+            'delay', [0])
+
+        delays = list(range(1, 33, 6))
+        p0 = [1, t1, 0]
+        bounds = ([0, 0, -1], [2, 40, 1])
+
+        exp = T1Experiment(0, delays)
+        data = exp.run(backend, noise_model=noise_model,
+                       fit_p0=p0, fit_bounds=bounds,
+                       instruction_durations=instruction_durations)
+
+
+if __name__ == '__main__':
+    unittest.main()

From b980a194cef47054d6ec06c1092b13b5c19265ad Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 4 Mar 2021 14:50:28 +0200
Subject: [PATCH 02/59] --amend

---
 qiskit_experiments/characterization/__init__.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 qiskit_experiments/characterization/__init__.py

diff --git a/qiskit_experiments/characterization/__init__.py b/qiskit_experiments/characterization/__init__.py
new file mode 100644
index 0000000000..280b38dfb8
--- /dev/null
+++ b/qiskit_experiments/characterization/__init__.py
@@ -0,0 +1,15 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Qiskit Experiments Characterziation."""
+
+from .t1_experiment import T1Experiment

From 0ec5d647747545bebcfc46e544cd9cd876f403d0 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 4 Mar 2021 16:00:29 +0200
Subject: [PATCH 03/59] black

---
 qiskit_experiments/__init__.py                |  1 -
 .../characterization/t1_experiment.py         | 33 +++++++++----------
 test/test_t1.py                               | 21 ++++++------
 3 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/qiskit_experiments/__init__.py b/qiskit_experiments/__init__.py
index 2ac660043c..42e800cb3c 100644
--- a/qiskit_experiments/__init__.py
+++ b/qiskit_experiments/__init__.py
@@ -20,4 +20,3 @@
 # Experiment modules
 from . import composite
 from . import characterization
-
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 7876313c4c..40df88418c 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -45,12 +45,12 @@ def _run_analysis(self, experiment_data, **params) -> Tuple[AnalysisResult, None
 
         prob1 = {}
         for circ in experiment_data._data:
-            delay = circ['metadata']['delay']
-            count0 = circ['counts'].get('0', 0)
-            count1 = circ['counts'].get('1', 0)
+            delay = circ["metadata"]["delay"]
+            count0 = circ["counts"].get("0", 0)
+            count1 = circ["counts"].get("1", 0)
             shots = count0 + count1
             mean = count1 / shots
-            std = np.sqrt(mean * (1-mean) / shots)
+            std = np.sqrt(mean * (1 - mean) / shots)
             # problem for the fitter if one of the std points is
             # exactly zero
             if std == 0:
@@ -68,11 +68,11 @@ def _run_analysis(self, experiment_data, **params) -> Tuple[AnalysisResult, None
         def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
-        fit_out, _ = \
-            curve_fit(exp_fit_fun, delays, means, sigma=stds,
-                      p0=params['fit_p0'], bounds=params['fit_bounds'])
+        fit_out, _ = curve_fit(
+            exp_fit_fun, delays, means, sigma=stds, p0=params["fit_p0"], bounds=params["fit_bounds"]
+        )
 
-        analysis_result = AnalysisResult({'value': fit_out[1]})
+        analysis_result = AnalysisResult({"value": fit_out[1]})
         return analysis_result, None
 
 
@@ -81,10 +81,7 @@ class T1Experiment(BaseExperiment):
 
     __analysis_class__ = T1Analysis
 
-    def __init__(self,
-                 qubit: int,
-                 delays: Union[List[float], np.array],
-                 unit: str = 'dt'):
+    def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str = "dt"):
         """
         Initialize the T1 experiment class
 
@@ -97,8 +94,9 @@ def __init__(self,
         self._unit = unit
         super().__init__([qubit], type(self).__name__)
 
-    def circuits(self, backend: Optional["Backend"] = None,
-                 **circuit_options) -> List[QuantumCircuit]:
+    def circuits(
+        self, backend: Optional["Backend"] = None, **circuit_options
+    ) -> List[QuantumCircuit]:
         """
         Return a list of experiment circuits
 
@@ -120,9 +118,10 @@ def circuits(self, backend: Optional["Backend"] = None,
 
             # pylint: disable = eval-used
             circ.metadata = {
-                'experiment_type': self._type,
-                'qubit': self.physical_qubits[0],
-                'delay': delay}
+                "experiment_type": self._type,
+                "qubit": self.physical_qubits[0],
+                "delay": delay,
+            }
 
             circuits.append(circ)
 
diff --git a/test/test_t1.py b/test/test_t1.py
index 2792dc8e33..9ca3f973fb 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -27,14 +27,13 @@
 from qiskit_experiments.characterization import T1Experiment
 
 backend = QasmSimulator()
-instruction_durations = \
-                      [('measure', [0], 3, 'dt'),
-                       ('x', [0], 3, 'dt')]
+instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
 gate_time = 0.1
 
 # Fix seed for simulations
 SEED = 9000
 
+
 class TestT1(unittest.TestCase):
     """
     Test measurement of T1
@@ -50,19 +49,21 @@ def test_t1(self):
         t1 = 25
 
         noise_model = NoiseModel()
-        noise_model.add_quantum_error(
-            thermal_relaxation_error(t1, 2*t1, gate_time),
-            'delay', [0])
+        noise_model.add_quantum_error(thermal_relaxation_error(t1, 2 * t1, gate_time), "delay", [0])
 
         delays = list(range(1, 33, 6))
         p0 = [1, t1, 0]
         bounds = ([0, 0, -1], [2, 40, 1])
 
         exp = T1Experiment(0, delays)
-        data = exp.run(backend, noise_model=noise_model,
-                       fit_p0=p0, fit_bounds=bounds,
-                       instruction_durations=instruction_durations)
+        data = exp.run(
+            backend,
+            noise_model=noise_model,
+            fit_p0=p0,
+            fit_bounds=bounds,
+            instruction_durations=instruction_durations,
+        )
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

From 82ac1ebb2abbfedbe76bcf74163656f8fd71a8f3 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 4 Mar 2021 16:09:21 +0200
Subject: [PATCH 04/59] lint

---
 .../characterization/t1_experiment.py           |  4 ++--
 test/test_t1.py                                 | 17 +++++++----------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 40df88418c..9fc636ac41 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -34,7 +34,7 @@ def _run_analysis(self, experiment_data, **params) -> Tuple[AnalysisResult, None
         Calculate T1
 
         Args:
-            experiment_data: the experiment data to analyze
+            experiment_data (ExperimentData): the experiment data to analyze
             params: expected parameters therein are:
                    `fit_p0` and `fit_bounds` - to be passed to scipy.optimize.curve_fit
                                                as the `p0` and `bounds` parameters
@@ -110,7 +110,7 @@ def circuits(
 
         circuits = []
 
-        for circ_index, delay in enumerate(self._delays):
+        for delay in self._delays:
             circ = QuantumCircuit(1, 1)
             circ.x(0)
             circ.delay(delay, 0, self._unit)
diff --git a/test/test_t1.py b/test/test_t1.py
index 9ca3f973fb..ca43085896 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -17,18 +17,15 @@
 
 import unittest
 
-import numpy as np
-
 from qiskit.providers.aer import QasmSimulator
 from qiskit.providers.aer.noise.errors.standard_errors import thermal_relaxation_error
 from qiskit.providers.aer.noise import NoiseModel
 
-from qiskit_experiments.composite import BatchExperiment, ParallelExperiment
 from qiskit_experiments.characterization import T1Experiment
 
-backend = QasmSimulator()
-instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
-gate_time = 0.1
+BACKEND = QasmSimulator()
+INSTRUCTION_DURATIONS = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
+GATE_TIME = 0.1
 
 # Fix seed for simulations
 SEED = 9000
@@ -49,19 +46,19 @@ def test_t1(self):
         t1 = 25
 
         noise_model = NoiseModel()
-        noise_model.add_quantum_error(thermal_relaxation_error(t1, 2 * t1, gate_time), "delay", [0])
+        noise_model.add_quantum_error(thermal_relaxation_error(t1, 2 * t1, GATE_TIME), "delay", [0])
 
         delays = list(range(1, 33, 6))
         p0 = [1, t1, 0]
         bounds = ([0, 0, -1], [2, 40, 1])
 
         exp = T1Experiment(0, delays)
-        data = exp.run(
-            backend,
+        exp.run(
+            BACKEND,
             noise_model=noise_model,
             fit_p0=p0,
             fit_bounds=bounds,
-            instruction_durations=instruction_durations,
+            instruction_durations=INSTRUCTION_DURATIONS,
         )
 
 

From 8b6f5697f5467df4b100020e1bf46fe2a5c1e293 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 4 Mar 2021 16:15:10 +0200
Subject: [PATCH 05/59] fixed header

---
 qiskit_experiments/characterization/t1_experiment.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 9fc636ac41..9c3dc36f51 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-
 # This code is part of Qiskit.
 #
 # (C) Copyright IBM 2021.

From 87dc98fcb37d9661983f4a6b5c3f07353182bc70 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 4 Mar 2021 17:03:31 +0200
Subject: [PATCH 06/59] changing variable names

---
 qiskit_experiments/characterization/t1_experiment.py | 6 +++---
 test/test_t1.py                                      | 3 +--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 9c3dc36f51..65b4bc72b6 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -34,8 +34,8 @@ def _run_analysis(self, experiment_data, **params) -> Tuple[AnalysisResult, None
         Args:
             experiment_data (ExperimentData): the experiment data to analyze
             params: expected parameters therein are:
-                   `fit_p0` and `fit_bounds` - to be passed to scipy.optimize.curve_fit
-                                               as the `p0` and `bounds` parameters
+                   `p0` and `bounds` - to be passed to scipy.optimize.curve_fit
+                                       as the `p0` and `bounds` parameters
 
         Returns:
             The analysis result with the estimated T1
@@ -67,7 +67,7 @@ def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
         fit_out, _ = curve_fit(
-            exp_fit_fun, delays, means, sigma=stds, p0=params["fit_p0"], bounds=params["fit_bounds"]
+            exp_fit_fun, delays, means, sigma=stds, p0=params["p0"], bounds=params["bounds"]
         )
 
         analysis_result = AnalysisResult({"value": fit_out[1]})
diff --git a/test/test_t1.py b/test/test_t1.py
index ca43085896..0a1726228e 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -56,8 +56,7 @@ def test_t1(self):
         exp.run(
             BACKEND,
             noise_model=noise_model,
-            fit_p0=p0,
-            fit_bounds=bounds,
+            p0=p0, bounds=bounds,
             instruction_durations=INSTRUCTION_DURATIONS,
         )
 

From 4dadd6cca9f57a37d288c3077c1afbc89ad65a4a Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Sun, 7 Mar 2021 16:33:52 +0200
Subject: [PATCH 07/59] changed backend in t1 test

---
 .../characterization/t1_experiment.py         |  2 +
 test/test_t1.py                               | 95 +++++++++++++++----
 2 files changed, 79 insertions(+), 18 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 65b4bc72b6..80754c976c 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -111,7 +111,9 @@ def circuits(
         for delay in self._delays:
             circ = QuantumCircuit(1, 1)
             circ.x(0)
+            circ.barrier(0)
             circ.delay(delay, 0, self._unit)
+            circ.barrier(0)
             circ.measure(0, 0)
 
             # pylint: disable = eval-used
diff --git a/test/test_t1.py b/test/test_t1.py
index 0a1726228e..c0b9d528cc 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -16,20 +16,82 @@
 """
 
 import unittest
+import numpy as np
+from qiskit.providers import BaseBackend
+from qiskit.providers.models import BackendConfiguration
+from qiskit.result import Result
+from qiskit_experiments.characterization import T1Experiment
 
-from qiskit.providers.aer import QasmSimulator
-from qiskit.providers.aer.noise.errors.standard_errors import thermal_relaxation_error
-from qiskit.providers.aer.noise import NoiseModel
 
-from qiskit_experiments.characterization import T1Experiment
+class T1Backend(BaseBackend):
+    """
+    A simple and primitive backend, to be run by the T1 tests
+    """
+
+    def __init__(self, t1):
+        """
+        Initialize the T1 backend
+        """
+
+        configuration = BackendConfiguration(
+            't1_simulator', '0', int(1e6),
+            ['barrier', 'x', 'delay', 'measure'],
+            [], True, True, False, False, False,
+            int(1e6), None)
 
-BACKEND = QasmSimulator()
-INSTRUCTION_DURATIONS = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
-GATE_TIME = 0.1
+        self._t1 = t1
+        super().__init__(configuration)
 
-# Fix seed for simulations
-SEED = 9000
+    def run(self, qobj, **kwargs):
+        """
+        Run the T1 backend
+        """
+
+        shots = qobj.config.shots
+
+        result = {
+            'backend_name': 'T1 backend',
+            'backend_version': '0',
+            'qobj_id': 0,
+            'job_id': 0,
+            'success': True,
+            'results': []
+            }
+        
+        for circ in qobj.experiments:
+            counts = dict()
 
+            for _ in range(shots):
+                prob1 = np.zeros(circ.config.n_qubits)
+                clbits = np.zeros(circ.config.memory_slots, dtype=int)
+                           
+                for op in circ.instructions:
+                    qubit = op.qubits[0]
+                    if op.name == "x":
+                        prob1[qubit] = 1 - prob1[qubit]
+                    if op.name == "delay":
+                        prob1[qubit] = prob1[qubit] * np.exp(-op.params[0] / self._t1)
+                    if op.name == "measure":
+                        meas_res = np.random.binomial(1, prob1[qubit])
+                        clbits[op.memory[0]] = meas_res
+                        prob1[qubit] = meas_res
+
+                clstr = ''
+                for clbit in clbits[::-1]:
+                    clstr = clstr + str(clbit)
+
+                if clstr in counts:
+                    counts[clstr] += 1
+                else:
+                    counts[clstr] = 1
+                    
+            result['results'].append({'shots': shots,
+                                      'success': True,
+                                      'header': {'metadata': circ.header.metadata},
+                                      'data': {'counts': counts}})
+            
+        return Result.from_dict(result)        
+        
 
 class TestT1(unittest.TestCase):
     """
@@ -39,27 +101,24 @@ class TestT1(unittest.TestCase):
     def test_t1(self):
         """
         Test T1 experiment using a simulator.
-        Currently only verifies that there is no exception,
-        but does not verify accuracy of the estimate.
         """
 
         t1 = 25
 
-        noise_model = NoiseModel()
-        noise_model.add_quantum_error(thermal_relaxation_error(t1, 2 * t1, GATE_TIME), "delay", [0])
-
         delays = list(range(1, 33, 6))
         p0 = [1, t1, 0]
         bounds = ([0, 0, -1], [2, 40, 1])
+        instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
 
         exp = T1Experiment(0, delays)
-        exp.run(
-            BACKEND,
-            noise_model=noise_model,
+        res = exp.run(
+            T1Backend(t1),
             p0=p0, bounds=bounds,
-            instruction_durations=INSTRUCTION_DURATIONS,
+            instruction_durations=instruction_durations
         )
 
+        self.assertAlmostEqual(res.analysis_result(0)['value'], t1, delta=2)
+
 
 if __name__ == "__main__":
     unittest.main()

From 1a43b2e1c6998d818f2fa85ce1f3e0b630a1e003 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Sun, 7 Mar 2021 17:03:43 +0200
Subject: [PATCH 08/59] added a test of a parallel experiment with T1

---
 qiskit_experiments/base_experiment.py |  2 +-
 test/test_t1.py                       | 43 ++++++++++++++++++++++++---
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/base_experiment.py b/qiskit_experiments/base_experiment.py
index 5ec835599b..2dc428d947 100644
--- a/qiskit_experiments/base_experiment.py
+++ b/qiskit_experiments/base_experiment.py
@@ -111,7 +111,7 @@ def run(self, backend, experiment_data=None, **kwargs):
 
         # Generate and run circuits
         circuits = self.transpiled_circuits(backend, **kwargs)
-        qobj = assemble(circuits, backend)
+        qobj = assemble(circuits, backend, **kwargs)
         job = backend.run(qobj, **kwargs)
 
         # Add Job to ExperimentData
diff --git a/test/test_t1.py b/test/test_t1.py
index c0b9d528cc..129ec0e222 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -20,6 +20,7 @@
 from qiskit.providers import BaseBackend
 from qiskit.providers.models import BackendConfiguration
 from qiskit.result import Result
+from qiskit_experiments.composite import ParallelExperiment
 from qiskit_experiments.characterization import T1Experiment
 
 
@@ -70,7 +71,8 @@ def run(self, qobj, **kwargs):
                     if op.name == "x":
                         prob1[qubit] = 1 - prob1[qubit]
                     if op.name == "delay":
-                        prob1[qubit] = prob1[qubit] * np.exp(-op.params[0] / self._t1)
+                        if self._t1[qubit] is not None:
+                            prob1[qubit] = prob1[qubit] * np.exp(-op.params[0] / self._t1[qubit])
                     if op.name == "measure":
                         meas_res = np.random.binomial(1, prob1[qubit])
                         clbits[op.memory[0]] = meas_res
@@ -108,17 +110,50 @@ def test_t1(self):
         delays = list(range(1, 33, 6))
         p0 = [1, t1, 0]
         bounds = ([0, 0, -1], [2, 40, 1])
+
+        # dummy numbers to avoid exception triggerring
         instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
 
         exp = T1Experiment(0, delays)
         res = exp.run(
-            T1Backend(t1),
+            T1Backend([t1]),
             p0=p0, bounds=bounds,
-            instruction_durations=instruction_durations
-        )
+            instruction_durations=instruction_durations,
+            shots=10000
+            )
 
         self.assertAlmostEqual(res.analysis_result(0)['value'], t1, delta=2)
 
+    def test_t1_parallel(self):
+        """
+        Test parallel experiments of T1 using a simulator.
+        """
+
+        t1 = [25, 15]
+
+        delays = list(range(1, 33, 6))
+        p0 = [1, t1[0], 0]
+        bounds = ([0, 0, -1], [2, 40, 1])
+
+        # dummy numbers to avoid exception triggerring
+        instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
+
+        exp0 = T1Experiment(0, delays)
+        exp2 = T1Experiment(2, delays)
+        par_exp = ParallelExperiment([exp0, exp2])
+        res = par_exp.run(
+            T1Backend([t1[0], None, t1[1]]),
+            p0=p0, bounds=bounds,
+            instruction_durations=instruction_durations,
+            shots=10000
+            )
+
+        for i in range(2):
+            self.assertAlmostEqual(
+                res.component_experiment_data(i).analysis_result(0)['value'],
+                t1[i], delta=2
+                )
+
 
 if __name__ == "__main__":
     unittest.main()

From e36046de28e1cb3b99f5990bbc7d26b703348e0a Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 8 Mar 2021 17:54:07 +0200
Subject: [PATCH 09/59] preparation and readout error in t1 tests

---
 test/test_t1.py | 37 ++++++++++++++++++++++++++++++-------
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/test/test_t1.py b/test/test_t1.py
index 129ec0e222..c372dd0e6f 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -29,7 +29,10 @@ class T1Backend(BaseBackend):
     A simple and primitive backend, to be run by the T1 tests
     """
 
-    def __init__(self, t1):
+    def __init__(self, t1,
+                 initial_prob1=None,
+                 readout0to1=None,
+                 readout1to0=None):
         """
         Initialize the T1 backend
         """
@@ -41,6 +44,9 @@ def __init__(self, t1):
             int(1e6), None)
 
         self._t1 = t1
+        self._initial_prob1 = initial_prob1
+        self._readout0to1 = readout0to1
+        self._readout1to0 = readout1to0
         super().__init__(configuration)
 
     def run(self, qobj, **kwargs):
@@ -60,10 +66,25 @@ def run(self, qobj, **kwargs):
             }
         
         for circ in qobj.experiments:
+            nqubits = circ.config.n_qubits
             counts = dict()
 
+            if self._readout0to1 is None:
+                ro01 = np.zeros(nqubits)
+            else:
+                ro01 = self._readout0to1
+                
+            if self._readout1to0 is None:
+                ro10 = np.zeros(nqubits)
+            else:
+                ro10 = self._readout1to0
+
             for _ in range(shots):
-                prob1 = np.zeros(circ.config.n_qubits)
+                if self._initial_prob1 is None:
+                    prob1 = np.zeros(nqubits)
+                else:
+                    prob1 = self._initial_prob1.copy()
+
                 clbits = np.zeros(circ.config.memory_slots, dtype=int)
                            
                 for op in circ.instructions:
@@ -74,7 +95,7 @@ def run(self, qobj, **kwargs):
                         if self._t1[qubit] is not None:
                             prob1[qubit] = prob1[qubit] * np.exp(-op.params[0] / self._t1[qubit])
                     if op.name == "measure":
-                        meas_res = np.random.binomial(1, prob1[qubit])
+                        meas_res = np.random.binomial(1, prob1[qubit] * (1 - ro10[qubit]) + (1 - prob1[qubit]) * ro01[qubit])
                         clbits[op.memory[0]] = meas_res
                         prob1[qubit] = meas_res
 
@@ -86,7 +107,7 @@ def run(self, qobj, **kwargs):
                     counts[clstr] += 1
                 else:
                     counts[clstr] = 1
-                    
+
             result['results'].append({'shots': shots,
                                       'success': True,
                                       'header': {'metadata': circ.header.metadata},
@@ -116,13 +137,15 @@ def test_t1(self):
 
         exp = T1Experiment(0, delays)
         res = exp.run(
-            T1Backend([t1]),
+            T1Backend([t1], initial_prob1=[0.1],
+                      readout0to1=[0.1],
+                      readout1to0=[0.1]),
             p0=p0, bounds=bounds,
             instruction_durations=instruction_durations,
             shots=10000
             )
 
-        self.assertAlmostEqual(res.analysis_result(0)['value'], t1, delta=2)
+        self.assertAlmostEqual(res.analysis_result(0)['value'], t1, delta=3)
 
     def test_t1_parallel(self):
         """
@@ -151,7 +174,7 @@ def test_t1_parallel(self):
         for i in range(2):
             self.assertAlmostEqual(
                 res.component_experiment_data(i).analysis_result(0)['value'],
-                t1[i], delta=2
+                t1[i], delta=3
                 )
 
 

From 8e7d313b8e5e27db1b579c319eec2a0a778792f4 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 8 Mar 2021 21:29:30 +0200
Subject: [PATCH 10/59] p0 and bounds as explicit function parameters

---
 qiskit_experiments/characterization/t1_experiment.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 80754c976c..66786c181e 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -27,15 +27,14 @@
 class T1Analysis(BaseAnalysis):
     """T1 Experiment result analysis class."""
 
-    def _run_analysis(self, experiment_data, **params) -> Tuple[AnalysisResult, None]:
+    def _run_analysis(self, experiment_data, p0, bounds, **kwargs) -> Tuple[AnalysisResult, None]:
         """
         Calculate T1
 
         Args:
             experiment_data (ExperimentData): the experiment data to analyze
-            params: expected parameters therein are:
-                   `p0` and `bounds` - to be passed to scipy.optimize.curve_fit
-                                       as the `p0` and `bounds` parameters
+            p0 (list): to be passed to scipy.optimize.curve_fit, see documentation there
+            bounds (tuple): to be passed to scipy.optimize.curve_fit, see documentation there
 
         Returns:
             The analysis result with the estimated T1
@@ -67,7 +66,7 @@ def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
         fit_out, _ = curve_fit(
-            exp_fit_fun, delays, means, sigma=stds, p0=params["p0"], bounds=params["bounds"]
+            exp_fit_fun, delays, means, sigma=stds, p0=p0, bounds=bounds
         )
 
         analysis_result = AnalysisResult({"value": fit_out[1]})

From f51c76a78d7622b9adb7f449d396a1097bf1bc8b Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 8 Mar 2021 21:31:36 +0200
Subject: [PATCH 11/59] black

---
 .../characterization/t1_experiment.py         |  4 +-
 test/test_t1.py                               | 91 +++++++++++--------
 2 files changed, 52 insertions(+), 43 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 66786c181e..9115cd87b0 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -65,9 +65,7 @@ def _run_analysis(self, experiment_data, p0, bounds, **kwargs) -> Tuple[Analysis
         def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
-        fit_out, _ = curve_fit(
-            exp_fit_fun, delays, means, sigma=stds, p0=p0, bounds=bounds
-        )
+        fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stds, p0=p0, bounds=bounds)
 
         analysis_result = AnalysisResult({"value": fit_out[1]})
         return analysis_result, None
diff --git a/test/test_t1.py b/test/test_t1.py
index c372dd0e6f..474ee1ede8 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -29,19 +29,25 @@ class T1Backend(BaseBackend):
     A simple and primitive backend, to be run by the T1 tests
     """
 
-    def __init__(self, t1,
-                 initial_prob1=None,
-                 readout0to1=None,
-                 readout1to0=None):
+    def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None):
         """
         Initialize the T1 backend
         """
 
         configuration = BackendConfiguration(
-            't1_simulator', '0', int(1e6),
-            ['barrier', 'x', 'delay', 'measure'],
-            [], True, True, False, False, False,
-            int(1e6), None)
+            "t1_simulator",
+            "0",
+            int(1e6),
+            ["barrier", "x", "delay", "measure"],
+            [],
+            True,
+            True,
+            False,
+            False,
+            False,
+            int(1e6),
+            None,
+        )
 
         self._t1 = t1
         self._initial_prob1 = initial_prob1
@@ -57,14 +63,14 @@ def run(self, qobj, **kwargs):
         shots = qobj.config.shots
 
         result = {
-            'backend_name': 'T1 backend',
-            'backend_version': '0',
-            'qobj_id': 0,
-            'job_id': 0,
-            'success': True,
-            'results': []
-            }
-        
+            "backend_name": "T1 backend",
+            "backend_version": "0",
+            "qobj_id": 0,
+            "job_id": 0,
+            "success": True,
+            "results": [],
+        }
+
         for circ in qobj.experiments:
             nqubits = circ.config.n_qubits
             counts = dict()
@@ -73,7 +79,7 @@ def run(self, qobj, **kwargs):
                 ro01 = np.zeros(nqubits)
             else:
                 ro01 = self._readout0to1
-                
+
             if self._readout1to0 is None:
                 ro10 = np.zeros(nqubits)
             else:
@@ -86,7 +92,7 @@ def run(self, qobj, **kwargs):
                     prob1 = self._initial_prob1.copy()
 
                 clbits = np.zeros(circ.config.memory_slots, dtype=int)
-                           
+
                 for op in circ.instructions:
                     qubit = op.qubits[0]
                     if op.name == "x":
@@ -95,11 +101,13 @@ def run(self, qobj, **kwargs):
                         if self._t1[qubit] is not None:
                             prob1[qubit] = prob1[qubit] * np.exp(-op.params[0] / self._t1[qubit])
                     if op.name == "measure":
-                        meas_res = np.random.binomial(1, prob1[qubit] * (1 - ro10[qubit]) + (1 - prob1[qubit]) * ro01[qubit])
+                        meas_res = np.random.binomial(
+                            1, prob1[qubit] * (1 - ro10[qubit]) + (1 - prob1[qubit]) * ro01[qubit]
+                        )
                         clbits[op.memory[0]] = meas_res
                         prob1[qubit] = meas_res
 
-                clstr = ''
+                clstr = ""
                 for clbit in clbits[::-1]:
                     clstr = clstr + str(clbit)
 
@@ -108,13 +116,17 @@ def run(self, qobj, **kwargs):
                 else:
                     counts[clstr] = 1
 
-            result['results'].append({'shots': shots,
-                                      'success': True,
-                                      'header': {'metadata': circ.header.metadata},
-                                      'data': {'counts': counts}})
-            
-        return Result.from_dict(result)        
-        
+            result["results"].append(
+                {
+                    "shots": shots,
+                    "success": True,
+                    "header": {"metadata": circ.header.metadata},
+                    "data": {"counts": counts},
+                }
+            )
+
+        return Result.from_dict(result)
+
 
 class TestT1(unittest.TestCase):
     """
@@ -137,15 +149,14 @@ def test_t1(self):
 
         exp = T1Experiment(0, delays)
         res = exp.run(
-            T1Backend([t1], initial_prob1=[0.1],
-                      readout0to1=[0.1],
-                      readout1to0=[0.1]),
-            p0=p0, bounds=bounds,
+            T1Backend([t1], initial_prob1=[0.1], readout0to1=[0.1], readout1to0=[0.1]),
+            p0=p0,
+            bounds=bounds,
             instruction_durations=instruction_durations,
-            shots=10000
-            )
+            shots=10000,
+        )
 
-        self.assertAlmostEqual(res.analysis_result(0)['value'], t1, delta=3)
+        self.assertAlmostEqual(res.analysis_result(0)["value"], t1, delta=3)
 
     def test_t1_parallel(self):
         """
@@ -166,16 +177,16 @@ def test_t1_parallel(self):
         par_exp = ParallelExperiment([exp0, exp2])
         res = par_exp.run(
             T1Backend([t1[0], None, t1[1]]),
-            p0=p0, bounds=bounds,
+            p0=p0,
+            bounds=bounds,
             instruction_durations=instruction_durations,
-            shots=10000
-            )
+            shots=10000,
+        )
 
         for i in range(2):
             self.assertAlmostEqual(
-                res.component_experiment_data(i).analysis_result(0)['value'],
-                t1[i], delta=3
-                )
+                res.component_experiment_data(i).analysis_result(0)["value"], t1[i], delta=3
+            )
 
 
 if __name__ == "__main__":

From 23bd8395013737f754e7afe63ae8f7671706fe24 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 9 Mar 2021 10:19:46 +0200
Subject: [PATCH 12/59] a small implementation change with t1

---
 .../characterization/t1_experiment.py         | 29 ++++++++-----------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 9115cd87b0..26cb71abe3 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -40,32 +40,27 @@ def _run_analysis(self, experiment_data, p0, bounds, **kwargs) -> Tuple[Analysis
             The analysis result with the estimated T1
         """
 
-        prob1 = {}
-        for circ in experiment_data._data:
-            delay = circ["metadata"]["delay"]
+        size = len(experiment_data._data)
+        delays = np.zeros(size, dtype=float)
+        means = np.zeros(size, dtype=float)
+        stddevs = np.zeros(size, dtype=float)
+
+        for i, circ in enumerate(experiment_data._data):
+            delays[i] = circ["metadata"]["delay"]
             count0 = circ["counts"].get("0", 0)
             count1 = circ["counts"].get("1", 0)
             shots = count0 + count1
-            mean = count1 / shots
-            std = np.sqrt(mean * (1 - mean) / shots)
+            means[i] = count1 / shots
+            stddevs[i] = np.sqrt(means[i] * (1 - means[i]) / shots)
             # problem for the fitter if one of the std points is
             # exactly zero
-            if std == 0:
-                std = 1e-4
-            prob1[delay] = (mean, std)
-
-        delays = []
-        means = []
-        stds = []
-        for delay in sorted(prob1):
-            delays.append(delay)
-            means.append(prob1[delay][0])
-            stds.append(prob1[delay][1])
+            if stddevs[i] == 0:
+                stddevs[i] = 1e-4
 
         def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
-        fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stds, p0=p0, bounds=bounds)
+        fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stddevs, p0=p0, bounds=bounds)
 
         analysis_result = AnalysisResult({"value": fit_out[1]})
         return analysis_result, None

From 3ca68ea3797b0f22a27efd8ab118870fad16f885 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 9 Mar 2021 11:00:42 +0200
Subject: [PATCH 13/59] added documentation to unit in t1

---
 qiskit_experiments/characterization/t1_experiment.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 26cb71abe3..ebe276945c 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -78,7 +78,8 @@ def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str =
         Args:
             qubit: the qubit whose T1 is to be estimated
             delays: delay times of the experiments
-            unit: time unit of `delays`
+            unit: unit of the duration. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
+                Default is ``dt``, i.e. integer time unit depending on the target backend.
         """
         self._delays = delays
         self._unit = unit

From 3544e1cd96235dc00cf9162deee553190e960dc0 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 9 Mar 2021 11:16:13 +0200
Subject: [PATCH 14/59] removed circuit_options from parameter list of circuits
 in t1

---
 qiskit_experiments/characterization/t1_experiment.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index ebe276945c..5821af07af 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -85,15 +85,12 @@ def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str =
         self._unit = unit
         super().__init__([qubit], type(self).__name__)
 
-    def circuits(
-        self, backend: Optional["Backend"] = None, **circuit_options
-    ) -> List[QuantumCircuit]:
+    def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
         """
         Return a list of experiment circuits
 
         Args:
             backend: a backend object
-            circuit_options: kwarg options for the function
 
         Returns:
             The experiment circuits

From 6f6736242d7dfbff617efab01f729d28487d3c8c Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 9 Mar 2021 11:23:19 +0200
Subject: [PATCH 15/59] a minor doc change

---
 qiskit_experiments/characterization/t1_experiment.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 5821af07af..fa33901ace 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -90,7 +90,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
         Return a list of experiment circuits
 
         Args:
-            backend: a backend object
+            backend: Optional, a backend object
 
         Returns:
             The experiment circuits

From c934818f0519f63d427669a36f2a518b0765158c Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 9 Mar 2021 13:38:57 +0200
Subject: [PATCH 16/59] default values to p0 and bounds

---
 qiskit_experiments/characterization/t1_experiment.py | 12 +++++++++---
 test/test_t1.py                                      |  6 +-----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index fa33901ace..2a55a84642 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -27,14 +27,14 @@
 class T1Analysis(BaseAnalysis):
     """T1 Experiment result analysis class."""
 
-    def _run_analysis(self, experiment_data, p0, bounds, **kwargs) -> Tuple[AnalysisResult, None]:
+    def _run_analysis(self, experiment_data, p0=None, bounds=None, **kwargs) -> Tuple[AnalysisResult, None]:
         """
         Calculate T1
 
         Args:
             experiment_data (ExperimentData): the experiment data to analyze
-            p0 (list): to be passed to scipy.optimize.curve_fit, see documentation there
-            bounds (tuple): to be passed to scipy.optimize.curve_fit, see documentation there
+            p0 (list): Optional, to be passed to scipy.optimize.curve_fit, see documentation there
+            bounds (tuple): Optional, to be passed to scipy.optimize.curve_fit, see documentation there
 
         Returns:
             The analysis result with the estimated T1
@@ -60,6 +60,12 @@ def _run_analysis(self, experiment_data, p0, bounds, **kwargs) -> Tuple[Analysis
         def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
+        if p0 is None:
+            p0 = [1, np.mean(delays), 0]
+
+        if bounds is None:
+            bounds = ([0, 0, 0], [1, 500, 1])
+
         fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stddevs, p0=p0, bounds=bounds)
 
         analysis_result = AnalysisResult({"value": fit_out[1]})
diff --git a/test/test_t1.py b/test/test_t1.py
index 474ee1ede8..c7556b0c13 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -142,7 +142,7 @@ def test_t1(self):
 
         delays = list(range(1, 33, 6))
         p0 = [1, t1, 0]
-        bounds = ([0, 0, -1], [2, 40, 1])
+        bounds = ([0, 0, 0], [1, 40, 1])
 
         # dummy numbers to avoid exception triggerring
         instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
@@ -166,8 +166,6 @@ def test_t1_parallel(self):
         t1 = [25, 15]
 
         delays = list(range(1, 33, 6))
-        p0 = [1, t1[0], 0]
-        bounds = ([0, 0, -1], [2, 40, 1])
 
         # dummy numbers to avoid exception triggerring
         instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
@@ -177,8 +175,6 @@ def test_t1_parallel(self):
         par_exp = ParallelExperiment([exp0, exp2])
         res = par_exp.run(
             T1Backend([t1[0], None, t1[1]]),
-            p0=p0,
-            bounds=bounds,
             instruction_durations=instruction_durations,
             shots=10000,
         )

From aea763203c99511b25478195e47055fbd8d50e2b Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Wed, 10 Mar 2021 13:22:00 +0200
Subject: [PATCH 17/59] updated p0 and removed bounds

---
 .../characterization/t1_experiment.py         | 23 +++++++++++--------
 test/test_t1.py                               |  5 +---
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 2a55a84642..e5c73b7e78 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -27,14 +27,17 @@
 class T1Analysis(BaseAnalysis):
     """T1 Experiment result analysis class."""
 
-    def _run_analysis(self, experiment_data, p0=None, bounds=None, **kwargs) -> Tuple[AnalysisResult, None]:
+    def _run_analysis(self, experiment_data,
+                      t1_guess=None, amplitude_guess=None, offset_guess=None,
+                      **kwargs) -> Tuple[AnalysisResult, None]:
         """
         Calculate T1
 
         Args:
             experiment_data (ExperimentData): the experiment data to analyze
-            p0 (list): Optional, to be passed to scipy.optimize.curve_fit, see documentation there
-            bounds (tuple): Optional, to be passed to scipy.optimize.curve_fit, see documentation there
+            t1_guess: Optional, an initial guess of T1
+            amplitude_guess: Optional, an initial guess of the coefficient of the exponent
+            offset_guess: Optional, an initial guess of the offset
 
         Returns:
             The analysis result with the estimated T1
@@ -60,13 +63,15 @@ def _run_analysis(self, experiment_data, p0=None, bounds=None, **kwargs) -> Tupl
         def exp_fit_fun(x, a, tau, c):
             return a * np.exp(-x / tau) + c
 
-        if p0 is None:
-            p0 = [1, np.mean(delays), 0]
+        if t1_guess is None:
+            t1_guess = np.mean(delays)
+        if offset_guess is None:
+            offset_guess = means[-1]
+        if amplitude_guess is None:
+            amplitude_guess = means[0] - offset_guess
 
-        if bounds is None:
-            bounds = ([0, 0, 0], [1, 500, 1])
-
-        fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stddevs, p0=p0, bounds=bounds)
+        fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stddevs,
+                               p0=[amplitude_guess, t1_guess, offset_guess])
 
         analysis_result = AnalysisResult({"value": fit_out[1]})
         return analysis_result, None
diff --git a/test/test_t1.py b/test/test_t1.py
index c7556b0c13..6db23e259b 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -141,8 +141,6 @@ def test_t1(self):
         t1 = 25
 
         delays = list(range(1, 33, 6))
-        p0 = [1, t1, 0]
-        bounds = ([0, 0, 0], [1, 40, 1])
 
         # dummy numbers to avoid exception triggerring
         instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
@@ -150,8 +148,7 @@ def test_t1(self):
         exp = T1Experiment(0, delays)
         res = exp.run(
             T1Backend([t1], initial_prob1=[0.1], readout0to1=[0.1], readout1to0=[0.1]),
-            p0=p0,
-            bounds=bounds,
+            amplitude_guess=1, t1_guess=t1, offset_guess=0,
             instruction_durations=instruction_durations,
             shots=10000,
         )

From 4d180b1fdd072d83e296fdd87ec4611d43f875b8 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Wed, 10 Mar 2021 13:22:40 +0200
Subject: [PATCH 18/59] black

---
 qiskit_experiments/characterization/t1_experiment.py | 11 ++++++-----
 test/test_t1.py                                      |  4 +++-
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index e5c73b7e78..8d1591703f 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -27,9 +27,9 @@
 class T1Analysis(BaseAnalysis):
     """T1 Experiment result analysis class."""
 
-    def _run_analysis(self, experiment_data,
-                      t1_guess=None, amplitude_guess=None, offset_guess=None,
-                      **kwargs) -> Tuple[AnalysisResult, None]:
+    def _run_analysis(
+        self, experiment_data, t1_guess=None, amplitude_guess=None, offset_guess=None, **kwargs
+    ) -> Tuple[AnalysisResult, None]:
         """
         Calculate T1
 
@@ -70,8 +70,9 @@ def exp_fit_fun(x, a, tau, c):
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
 
-        fit_out, _ = curve_fit(exp_fit_fun, delays, means, sigma=stddevs,
-                               p0=[amplitude_guess, t1_guess, offset_guess])
+        fit_out, _ = curve_fit(
+            exp_fit_fun, delays, means, sigma=stddevs, p0=[amplitude_guess, t1_guess, offset_guess]
+        )
 
         analysis_result = AnalysisResult({"value": fit_out[1]})
         return analysis_result, None
diff --git a/test/test_t1.py b/test/test_t1.py
index 6db23e259b..c8c921ee1b 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -148,7 +148,9 @@ def test_t1(self):
         exp = T1Experiment(0, delays)
         res = exp.run(
             T1Backend([t1], initial_prob1=[0.1], readout0to1=[0.1], readout1to0=[0.1]),
-            amplitude_guess=1, t1_guess=t1, offset_guess=0,
+            amplitude_guess=1,
+            t1_guess=t1,
+            offset_guess=0,
             instruction_durations=instruction_durations,
             shots=10000,
         )

From 580f572d56faf3c18f6db1cc404b2a05cd54f47c Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Wed, 10 Mar 2021 17:41:24 +0200
Subject: [PATCH 19/59] return more info about t1 fit

---
 .../characterization/t1_experiment.py         | 33 +++++++++++++++++--
 test/test_t1.py                               | 12 +++----
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 8d1591703f..6ffc066238 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -70,11 +70,40 @@ def exp_fit_fun(x, a, tau, c):
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
 
-        fit_out, _ = curve_fit(
+        fit_out, fit_cov = curve_fit(
             exp_fit_fun, delays, means, sigma=stddevs, p0=[amplitude_guess, t1_guess, offset_guess]
         )
 
-        analysis_result = AnalysisResult({"value": fit_out[1]})
+        chisq = 0
+        for i in range(len(delays)):
+            chisq += (
+                exp_fit_fun(delays[i], fit_out[0], fit_out[1], fit_out[2]) - means[i]
+            ) ** 2 / stddevs[i] ** 2
+        chisq /= len(delays)
+
+        fit_err = np.sqrt(np.diag(fit_cov))
+
+        analysis_result = AnalysisResult(
+            {
+                "amplitude": fit_out[0],
+                "t1": fit_out[1],
+                "offset": fit_out[2],
+                "amplitude_err": fit_err[0],
+                "t1_err": fit_err[1],
+                "offset_err": fit_err[2],
+                "chisq": chisq,
+            }
+        )
+
+        analysis_result["is_good_fit"] = (
+            abs(analysis_result["amplitude"] - 1.0) < 0.1
+            and abs(analysis_result["offset"]) < 0.1
+            and analysis_result["chisq"] < 3
+            and analysis_result["amplitude_err"] < 0.1
+            and analysis_result["offset_err"] < 0.1
+            and analysis_result["t1_err"] < analysis_result["t1"]
+        )
+
         return analysis_result, None
 
 
diff --git a/test/test_t1.py b/test/test_t1.py
index c8c921ee1b..b80ede4198 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -140,14 +140,14 @@ def test_t1(self):
 
         t1 = 25
 
-        delays = list(range(1, 33, 6))
+        delays = list(range(1, 40, 3))
 
         # dummy numbers to avoid exception triggerring
         instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
 
         exp = T1Experiment(0, delays)
         res = exp.run(
-            T1Backend([t1], initial_prob1=[0.1], readout0to1=[0.1], readout1to0=[0.1]),
+            T1Backend([t1], initial_prob1=[0.02], readout0to1=[0.02], readout1to0=[0.02]),
             amplitude_guess=1,
             t1_guess=t1,
             offset_guess=0,
@@ -155,7 +155,7 @@ def test_t1(self):
             shots=10000,
         )
 
-        self.assertAlmostEqual(res.analysis_result(0)["value"], t1, delta=3)
+        self.assertTrue(res.analysis_result(0)["is_good_fit"])
 
     def test_t1_parallel(self):
         """
@@ -164,7 +164,7 @@ def test_t1_parallel(self):
 
         t1 = [25, 15]
 
-        delays = list(range(1, 33, 6))
+        delays = list(range(1, 40, 3))
 
         # dummy numbers to avoid exception triggerring
         instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
@@ -179,9 +179,7 @@ def test_t1_parallel(self):
         )
 
         for i in range(2):
-            self.assertAlmostEqual(
-                res.component_experiment_data(i).analysis_result(0)["value"], t1[i], delta=3
-            )
+            self.assertTrue(res.component_experiment_data(i).analysis_result(0)["is_good_fit"])
 
 
 if __name__ == "__main__":

From 0ede9efe2548c8db6972f351a68163c19649dbef Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 11 Mar 2021 10:15:13 +0200
Subject: [PATCH 20/59] a small change in t1 tests

---
 test/test_t1.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/test/test_t1.py b/test/test_t1.py
index b80ede4198..cb1e9b5ab0 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -153,9 +153,10 @@ def test_t1(self):
             offset_guess=0,
             instruction_durations=instruction_durations,
             shots=10000,
-        )
+        ).analysis_result(0)
 
-        self.assertTrue(res.analysis_result(0)["is_good_fit"])
+        self.assertTrue(res["is_good_fit"])
+        self.assertAlmostEqual(res["t1"], t1, delta=3)
 
     def test_t1_parallel(self):
         """
@@ -179,7 +180,9 @@ def test_t1_parallel(self):
         )
 
         for i in range(2):
-            self.assertTrue(res.component_experiment_data(i).analysis_result(0)["is_good_fit"])
+            sub_res = res.component_experiment_data(i).analysis_result(0)
+            self.assertTrue(sub_res["is_good_fit"])
+            self.assertAlmostEqual(sub_res["t1"], t1[i], delta=3)
 
 
 if __name__ == "__main__":

From 9d34c99802fe21f0eb9741ab1fa123f2c607d13d Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 11 Mar 2021 11:30:23 +0200
Subject: [PATCH 21/59] small improvements to t1

---
 .../characterization/t1_experiment.py         | 21 +++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 6ffc066238..6a2e4cdbf2 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -75,10 +75,10 @@ def exp_fit_fun(x, a, tau, c):
         )
 
         chisq = 0
-        for i in range(len(delays)):
+        for delay, mean, stddev in zip(delays, means, stddevs):
             chisq += (
-                exp_fit_fun(delays[i], fit_out[0], fit_out[1], fit_out[2]) - means[i]
-            ) ** 2 / stddevs[i] ** 2
+                exp_fit_fun(delay, fit_out[0], fit_out[1], fit_out[2]) - mean
+            ) ** 2 / stddev ** 2
         chisq /= len(delays)
 
         fit_err = np.sqrt(np.diag(fit_cov))
@@ -99,9 +99,12 @@ def exp_fit_fun(x, a, tau, c):
             abs(analysis_result["amplitude"] - 1.0) < 0.1
             and abs(analysis_result["offset"]) < 0.1
             and analysis_result["chisq"] < 3
-            and analysis_result["amplitude_err"] < 0.1
-            and analysis_result["offset_err"] < 0.1
-            and analysis_result["t1_err"] < analysis_result["t1"]
+            and (analysis_result["amplitude_err"] is None or analysis_result["amplitude_err"] < 0.1)
+            and (analysis_result["offset_err"] is None or analysis_result["offset_err"] < 0.1)
+            and (
+                analysis_result["t1_err"] is None
+                or analysis_result["t1_err"] < analysis_result["t1"]
+            )
         )
 
         return analysis_result, None
@@ -121,7 +124,13 @@ def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str =
             delays: delay times of the experiments
             unit: unit of the duration. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
                 Default is ``dt``, i.e. integer time unit depending on the target backend.
+
+        Raises:
+            ValueError: if the number of delays is smaller than 3
         """
+        if len(delays) < 3:
+            raise ValueError("T1 experiment: number of delays must be at least 3")
+
         self._delays = delays
         self._unit = unit
         super().__init__([qubit], type(self).__name__)

From 2067572b731d1208bf2288a5d432cc5ffebf8880 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 11 Mar 2021 14:40:41 +0200
Subject: [PATCH 22/59] exp_fit_fun and curve_fit wrapper in a shared space

---
 qiskit_experiments/base_analysis.py           | 33 +++++++++++++++++++
 .../characterization/t1_experiment.py         | 21 ++++--------
 2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/qiskit_experiments/base_analysis.py b/qiskit_experiments/base_analysis.py
index f6329fe203..b0321a1bf5 100644
--- a/qiskit_experiments/base_analysis.py
+++ b/qiskit_experiments/base_analysis.py
@@ -14,6 +14,8 @@
 """
 
 from abc import ABC, abstractmethod
+import numpy as np
+from scipy.optimize import curve_fit
 
 from qiskit.exceptions import QiskitError
 from .experiment_data import ExperimentData, AnalysisResult
@@ -90,3 +92,34 @@ def _run_analysis(self, experiment_data, **options):
                    None, a single figure, or a list of figures.
         """
         pass
+
+    @staticmethod
+    def exp_fit_fun(x, a, tau, c):
+        """
+        Exponential fit function
+        """
+        return a * np.exp(-x / tau) + c
+
+    # pylint: disable = invalid-name
+    @staticmethod
+    def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
+        """
+        A wrapper to curve_fit that calculates and returns fit_err
+        (square root of the diagonal of the covariance matrix) and chi square.
+
+        Arguments are identical to curve_fit arguments, with the following exceptions:
+        - The `sigma` parameter is mandatory.
+        - The order of arguments is slightly different.
+
+        Returns fit_out, fit_err, chisq
+        """
+        fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
+
+        chisq = 0
+        for x, y, sig in zip(xdata, ydata, sigma):
+            chisq += (f(x, *fit_out) - y) ** 2 / sig ** 2
+        chisq /= len(xdata)
+
+        fit_err = np.sqrt(np.diag(fit_cov))
+
+        return fit_out, fit_err, chisq
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 6a2e4cdbf2..7a1f9204d3 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -15,7 +15,6 @@
 
 from typing import List, Optional, Union, Tuple
 import numpy as np
-from scipy.optimize import curve_fit
 
 from qiskit.circuit import QuantumCircuit
 
@@ -60,9 +59,6 @@ def _run_analysis(
             if stddevs[i] == 0:
                 stddevs[i] = 1e-4
 
-        def exp_fit_fun(x, a, tau, c):
-            return a * np.exp(-x / tau) + c
-
         if t1_guess is None:
             t1_guess = np.mean(delays)
         if offset_guess is None:
@@ -70,19 +66,14 @@ def exp_fit_fun(x, a, tau, c):
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
 
-        fit_out, fit_cov = curve_fit(
-            exp_fit_fun, delays, means, sigma=stddevs, p0=[amplitude_guess, t1_guess, offset_guess]
+        fit_out, fit_err, chisq = BaseAnalysis.curve_fit_wrapper(
+            BaseAnalysis.exp_fit_fun,
+            delays,
+            means,
+            stddevs,
+            p0=[amplitude_guess, t1_guess, offset_guess],
         )
 
-        chisq = 0
-        for delay, mean, stddev in zip(delays, means, stddevs):
-            chisq += (
-                exp_fit_fun(delay, fit_out[0], fit_out[1], fit_out[2]) - mean
-            ) ** 2 / stddev ** 2
-        chisq /= len(delays)
-
-        fit_err = np.sqrt(np.diag(fit_cov))
-
         analysis_result = AnalysisResult(
             {
                 "amplitude": fit_out[0],

From 2ff0e3a922758046bef47f3e636409e33a471feb Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 11 Mar 2021 14:51:23 +0200
Subject: [PATCH 23/59] unit in circuit metadata and analysis result

---
 qiskit_experiments/characterization/t1_experiment.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 7a1f9204d3..bc1a88d529 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -83,6 +83,7 @@ def _run_analysis(
                 "t1_err": fit_err[1],
                 "offset_err": fit_err[2],
                 "chisq": chisq,
+                "unit": experiment_data._data[0]["metadata"]["unit"]
             }
         )
 
@@ -152,6 +153,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 "experiment_type": self._type,
                 "qubit": self.physical_qubits[0],
                 "delay": delay,
+                "unit": self._unit
             }
 
             circuits.append(circ)

From a0b30e5f0f88c2413f56629ae9b264d974a6e943 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 18 Mar 2021 18:45:36 +0200
Subject: [PATCH 24/59] lint

---
 qiskit_experiments/base_experiment.py                |  2 +-
 qiskit_experiments/characterization/t1_experiment.py | 11 +++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/base_experiment.py b/qiskit_experiments/base_experiment.py
index 274ce7566e..fb82f4646c 100644
--- a/qiskit_experiments/base_experiment.py
+++ b/qiskit_experiments/base_experiment.py
@@ -73,7 +73,7 @@ def __init__(self, qubits, experiment_type=None, circuit_options=None):
                                            physical qubits for the experiment.
             experiment_type (str): Optional, the experiment type string.
             circuit_options (Iterable): Optional, list of kwarg names for
-                                        the subclasses `circuit` method.
+                                        the subclassed `circuit` method.
 
         Raises:
             QiskitError: if qubits is a list and contains duplicates.
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index bc1a88d529..8a68ccd185 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -26,6 +26,7 @@
 class T1Analysis(BaseAnalysis):
     """T1 Experiment result analysis class."""
 
+    # pylint: disable=arguments-differ, unused-argument
     def _run_analysis(
         self, experiment_data, t1_guess=None, amplitude_guess=None, offset_guess=None, **kwargs
     ) -> Tuple[AnalysisResult, None]:
@@ -34,9 +35,10 @@ def _run_analysis(
 
         Args:
             experiment_data (ExperimentData): the experiment data to analyze
-            t1_guess: Optional, an initial guess of T1
-            amplitude_guess: Optional, an initial guess of the coefficient of the exponent
-            offset_guess: Optional, an initial guess of the offset
+            t1_guess (float): Optional, an initial guess of T1
+            amplitude_guess (float): Optional, an initial guess of the coefficient of the exponent
+            offset_guess (float): Optional, an initial guess of the offset
+            kwargs: Trailing unused function parameters
 
         Returns:
             The analysis result with the estimated T1
@@ -71,7 +73,7 @@ def _run_analysis(
             delays,
             means,
             stddevs,
-            p0=[amplitude_guess, t1_guess, offset_guess],
+            p0=[amplitude_guess, t1_guess, offset_guess]
         )
 
         analysis_result = AnalysisResult(
@@ -127,6 +129,7 @@ def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str =
         self._unit = unit
         super().__init__([qubit], type(self).__name__)
 
+    # pylint: disable=arguments-differ
     def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
         """
         Return a list of experiment circuits

From c443951c82ca7ee816312be9fec501b4ea8eefe5 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 22 Mar 2021 11:00:03 +0200
Subject: [PATCH 25/59] added a test to t1 analysis class

---
 .../characterization/__init__.py              |  2 +-
 .../characterization/t1_experiment.py         |  4 +--
 test/test_t1.py                               | 30 +++++++++++++++++--
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/characterization/__init__.py b/qiskit_experiments/characterization/__init__.py
index 280b38dfb8..6c7921d665 100644
--- a/qiskit_experiments/characterization/__init__.py
+++ b/qiskit_experiments/characterization/__init__.py
@@ -12,4 +12,4 @@
 
 """Qiskit Experiments Characterziation."""
 
-from .t1_experiment import T1Experiment
+from .t1_experiment import T1Experiment, T1Analysis
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 8a68ccd185..65fb944fc6 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -85,7 +85,7 @@ def _run_analysis(
                 "t1_err": fit_err[1],
                 "offset_err": fit_err[2],
                 "chisq": chisq,
-                "unit": experiment_data._data[0]["metadata"]["unit"]
+                "unit": experiment_data._data[0]["metadata"]["unit"],
             }
         )
 
@@ -156,7 +156,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 "experiment_type": self._type,
                 "qubit": self.physical_qubits[0],
                 "delay": delay,
-                "unit": self._unit
+                "unit": self._unit,
             }
 
             circuits.append(circ)
diff --git a/test/test_t1.py b/test/test_t1.py
index cb1e9b5ab0..9b36279ece 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -20,8 +20,9 @@
 from qiskit.providers import BaseBackend
 from qiskit.providers.models import BackendConfiguration
 from qiskit.result import Result
+from qiskit_experiments import ExperimentData
 from qiskit_experiments.composite import ParallelExperiment
-from qiskit_experiments.characterization import T1Experiment
+from qiskit_experiments.characterization import T1Experiment, T1Analysis
 
 
 class T1Backend(BaseBackend):
@@ -133,7 +134,7 @@ class TestT1(unittest.TestCase):
     Test measurement of T1
     """
 
-    def test_t1(self):
+    def test_t1_end2end(self):
         """
         Test T1 experiment using a simulator.
         """
@@ -184,6 +185,31 @@ def test_t1_parallel(self):
             self.assertTrue(sub_res["is_good_fit"])
             self.assertAlmostEqual(sub_res["t1"], t1[i], delta=3)
 
+    def test_t1_analysis(self):
+        """
+        Test T1Analysis
+        """
+
+        data = ExperimentData(None)
+        numbers = [750, 1800, 2750, 3550, 4250, 4850, 5450, 5900, 6400, 6800, 7000, 7350, 7700]
+
+        for i, count0 in enumerate(numbers):
+            data._data.append(
+                {
+                    "counts": {"0": count0, "1": 10000 - count0},
+                    "metadata": {
+                        "delay": 3 * i + 1,
+                        "experiment_type": "T1Experiment",
+                        "qubit": 0,
+                        "unit": "dt",
+                    },
+                }
+            )
+
+        res = T1Analysis()._run_analysis(data)[0]
+        self.assertTrue(res["is_good_fit"])
+        self.assertAlmostEqual(res["t1"], 25, delta=3)
+
 
 if __name__ == "__main__":
     unittest.main()

From be7fcaec337b59cd2b8ed7686cb5992f560ce8a7 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 22 Mar 2021 13:33:52 +0200
Subject: [PATCH 26/59] changed the result structure in t1

---
 qiskit_experiments/base_analysis.py           |  2 +-
 .../characterization/t1_experiment.py         | 43 ++++++++++---------
 test/test_t1.py                               | 12 +++---
 3 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/qiskit_experiments/base_analysis.py b/qiskit_experiments/base_analysis.py
index b0321a1bf5..2379ab7695 100644
--- a/qiskit_experiments/base_analysis.py
+++ b/qiskit_experiments/base_analysis.py
@@ -122,4 +122,4 @@ def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
 
         fit_err = np.sqrt(np.diag(fit_cov))
 
-        return fit_out, fit_err, chisq
+        return fit_out, fit_err, fit_cov, chisq
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 65fb944fc6..89b6d3553f 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -68,38 +68,41 @@ def _run_analysis(
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
 
-        fit_out, fit_err, chisq = BaseAnalysis.curve_fit_wrapper(
+        fit_out, fit_err, fit_cov, chisq = BaseAnalysis.curve_fit_wrapper(
             BaseAnalysis.exp_fit_fun,
             delays,
             means,
             stddevs,
-            p0=[amplitude_guess, t1_guess, offset_guess]
+            p0=[amplitude_guess, t1_guess, offset_guess],
         )
 
         analysis_result = AnalysisResult(
             {
-                "amplitude": fit_out[0],
-                "t1": fit_out[1],
-                "offset": fit_out[2],
-                "amplitude_err": fit_err[0],
-                "t1_err": fit_err[1],
-                "offset_err": fit_err[2],
-                "chisq": chisq,
+                "value": fit_out[1],
+                "stderr": fit_err[1],
                 "unit": experiment_data._data[0]["metadata"]["unit"],
+                "label": "T1",
+                "fit": {
+                    "params": fit_out,
+                    "stderr": fit_err,
+                    "labels": ["amplitude", "T1", "offset"],
+                    "chisq": chisq,
+                    "cov": fit_cov,
+                },
             }
         )
 
-        analysis_result["is_good_fit"] = (
-            abs(analysis_result["amplitude"] - 1.0) < 0.1
-            and abs(analysis_result["offset"]) < 0.1
-            and analysis_result["chisq"] < 3
-            and (analysis_result["amplitude_err"] is None or analysis_result["amplitude_err"] < 0.1)
-            and (analysis_result["offset_err"] is None or analysis_result["offset_err"] < 0.1)
-            and (
-                analysis_result["t1_err"] is None
-                or analysis_result["t1_err"] < analysis_result["t1"]
-            )
-        )
+        if (
+            abs(fit_out[0] - 1.0) < 0.1
+            and abs(fit_out[2]) < 0.1
+            and chisq < 3
+            and (fit_err[0] is None or fit_err[0] < 0.1)
+            and (fit_err[1] is None or fit_err[1] < fit_out[1])
+            and (fit_err[2] is None or fit_err[2] < 0.1)
+        ):
+            analysis_result["quality"] = "computer_good"
+        else:
+            analysis_result["quality"] = "computer_bad"
 
         return analysis_result, None
 
diff --git a/test/test_t1.py b/test/test_t1.py
index 9b36279ece..6dd24371ef 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -156,8 +156,8 @@ def test_t1_end2end(self):
             shots=10000,
         ).analysis_result(0)
 
-        self.assertTrue(res["is_good_fit"])
-        self.assertAlmostEqual(res["t1"], t1, delta=3)
+        self.assertEqual(res["quality"], "computer_good")
+        self.assertAlmostEqual(res["value"], t1, delta=3)
 
     def test_t1_parallel(self):
         """
@@ -182,8 +182,8 @@ def test_t1_parallel(self):
 
         for i in range(2):
             sub_res = res.component_experiment_data(i).analysis_result(0)
-            self.assertTrue(sub_res["is_good_fit"])
-            self.assertAlmostEqual(sub_res["t1"], t1[i], delta=3)
+            self.assertTrue(sub_res["quality"], "computer_good")
+            self.assertAlmostEqual(sub_res["value"], t1[i], delta=3)
 
     def test_t1_analysis(self):
         """
@@ -207,8 +207,8 @@ def test_t1_analysis(self):
             )
 
         res = T1Analysis()._run_analysis(data)[0]
-        self.assertTrue(res["is_good_fit"])
-        self.assertAlmostEqual(res["t1"], 25, delta=3)
+        self.assertEqual(res["quality"], "computer_good")
+        self.assertAlmostEqual(res["value"], 25, delta=3)
 
 
 if __name__ == "__main__":

From 3b7d3bdb5678731817b85c19145171034b565c7f Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 22 Mar 2021 14:57:50 +0200
Subject: [PATCH 27/59] moved functions from BaseAnalysis to a separate file

---
 qiskit_experiments/base_analysis.py           | 33 ------------
 .../characterization/analysis_functions.py    | 51 +++++++++++++++++++
 .../characterization/t1_experiment.py         |  5 +-
 3 files changed, 54 insertions(+), 35 deletions(-)
 create mode 100644 qiskit_experiments/characterization/analysis_functions.py

diff --git a/qiskit_experiments/base_analysis.py b/qiskit_experiments/base_analysis.py
index 2379ab7695..f6329fe203 100644
--- a/qiskit_experiments/base_analysis.py
+++ b/qiskit_experiments/base_analysis.py
@@ -14,8 +14,6 @@
 """
 
 from abc import ABC, abstractmethod
-import numpy as np
-from scipy.optimize import curve_fit
 
 from qiskit.exceptions import QiskitError
 from .experiment_data import ExperimentData, AnalysisResult
@@ -92,34 +90,3 @@ def _run_analysis(self, experiment_data, **options):
                    None, a single figure, or a list of figures.
         """
         pass
-
-    @staticmethod
-    def exp_fit_fun(x, a, tau, c):
-        """
-        Exponential fit function
-        """
-        return a * np.exp(-x / tau) + c
-
-    # pylint: disable = invalid-name
-    @staticmethod
-    def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
-        """
-        A wrapper to curve_fit that calculates and returns fit_err
-        (square root of the diagonal of the covariance matrix) and chi square.
-
-        Arguments are identical to curve_fit arguments, with the following exceptions:
-        - The `sigma` parameter is mandatory.
-        - The order of arguments is slightly different.
-
-        Returns fit_out, fit_err, chisq
-        """
-        fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
-
-        chisq = 0
-        for x, y, sig in zip(xdata, ydata, sigma):
-            chisq += (f(x, *fit_out) - y) ** 2 / sig ** 2
-        chisq /= len(xdata)
-
-        fit_err = np.sqrt(np.diag(fit_cov))
-
-        return fit_out, fit_err, fit_cov, chisq
diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
new file mode 100644
index 0000000000..02aaed925f
--- /dev/null
+++ b/qiskit_experiments/characterization/analysis_functions.py
@@ -0,0 +1,51 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""
+Functions for fitting parameters.
+"""
+
+import numpy as np
+from scipy.optimize import curve_fit
+
+
+def exp_fit_fun(x, a, tau, c):
+    """
+    Exponential fit function
+    """
+    return a * np.exp(-x / tau) + c
+
+
+# pylint: disable = invalid-name
+def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
+    """
+    A wrapper to curve_fit that calculates and returns fit_err
+    (square root of the diagonal of the covariance matrix) and chi square.
+
+    Args:
+        f (callable): see documentation of curve_fit in scipy.optimize
+        xdata (array_like or object): see documentation of curve_fit in scipy.optimize
+        ydata (array_like): see documentation of curve_fit in scipy.optimize
+        sigma (None or 1-dimensional sequence or 2-dimensional array):
+        kwargs: additional paramters to be passed to curve_fit
+
+    Returns fit_out, fit_err, chisq
+    """
+    fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
+
+    chisq = 0
+    for x, y, sig in zip(xdata, ydata, sigma):
+        chisq += (f(x, *fit_out) - y) ** 2 / sig ** 2
+    chisq /= len(xdata)
+
+    fit_err = np.sqrt(np.diag(fit_cov))
+
+    return fit_out, fit_err, fit_cov, chisq
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 89b6d3553f..82e8b1f52c 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -21,6 +21,7 @@
 from qiskit_experiments.base_experiment import BaseExperiment
 from qiskit_experiments.base_analysis import BaseAnalysis
 from qiskit_experiments import AnalysisResult
+from .analysis_functions import exp_fit_fun, curve_fit_wrapper
 
 
 class T1Analysis(BaseAnalysis):
@@ -68,8 +69,8 @@ def _run_analysis(
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
 
-        fit_out, fit_err, fit_cov, chisq = BaseAnalysis.curve_fit_wrapper(
-            BaseAnalysis.exp_fit_fun,
+        fit_out, fit_err, fit_cov, chisq = curve_fit_wrapper(
+            exp_fit_fun,
             delays,
             means,
             stddevs,

From e80e7fe6876a23d0c1d17e4a02eec0a54fefb45c Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 22 Mar 2021 16:12:46 +0200
Subject: [PATCH 28/59] lint

---
 .../characterization/analysis_functions.py          | 13 +++++++++----
 .../characterization/t1_experiment.py               |  1 +
 test/test_t1.py                                     |  3 ++-
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
index 02aaed925f..b88d840179 100644
--- a/qiskit_experiments/characterization/analysis_functions.py
+++ b/qiskit_experiments/characterization/analysis_functions.py
@@ -32,12 +32,17 @@ def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
 
     Args:
         f (callable): see documentation of curve_fit in scipy.optimize
-        xdata (array_like or object): see documentation of curve_fit in scipy.optimize
-        ydata (array_like): see documentation of curve_fit in scipy.optimize
-        sigma (None or 1-dimensional sequence or 2-dimensional array):
+        xdata (list): see documentation of curve_fit in scipy.optimize
+        ydata (list): see documentation of curve_fit in scipy.optimize
+        sigma (list): see documentation of curve_fit in scipy.optimize
         kwargs: additional paramters to be passed to curve_fit
 
-    Returns fit_out, fit_err, chisq
+    Returns:
+        list: fitted parameters
+        list: error on fitted parameters
+              (square root of the diagonal of the covariance matrix)
+        matrix: the covariance matrix
+        float: chi-square, which is the function that's minimized when fitting
     """
     fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
 
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 82e8b1f52c..5d9658b7b0 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -93,6 +93,7 @@ def _run_analysis(
             }
         )
 
+        #pylint: disable = too-many-boolean-expressions
         if (
             abs(fit_out[0] - 1.0) < 0.1
             and abs(fit_out[2]) < 0.1
diff --git a/test/test_t1.py b/test/test_t1.py
index 6dd24371ef..7f8cba134f 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -56,7 +56,8 @@ def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None):
         self._readout1to0 = readout1to0
         super().__init__(configuration)
 
-    def run(self, qobj, **kwargs):
+    #pylint: disable = arguments-differ
+    def run(self, qobj):
         """
         Run the T1 backend
         """

From 2daa615010495988534d63b208b457fe1c58f5fb Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 25 Mar 2021 13:40:30 +0200
Subject: [PATCH 29/59] review comments

---
 .../characterization/analysis_functions.py    |  2 +-
 test/test_t1.py                               | 24 +++++++++----------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
index b88d840179..5aed02f7ca 100644
--- a/qiskit_experiments/characterization/analysis_functions.py
+++ b/qiskit_experiments/characterization/analysis_functions.py
@@ -42,7 +42,7 @@ def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
         list: error on fitted parameters
               (square root of the diagonal of the covariance matrix)
         matrix: the covariance matrix
-        float: chi-square, which is the function that's minimized when fitting
+        float: chi-square
     """
     fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
 
diff --git a/test/test_t1.py b/test/test_t1.py
index 7f8cba134f..48092f17e7 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -36,18 +36,18 @@ def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None):
         """
 
         configuration = BackendConfiguration(
-            "t1_simulator",
-            "0",
-            int(1e6),
-            ["barrier", "x", "delay", "measure"],
-            [],
-            True,
-            True,
-            False,
-            False,
-            False,
-            int(1e6),
-            None,
+            backend_name="t1_simulator",
+            backend_version="0",
+            n_qubits=int(1e6),
+            basis_gates=["barrier", "x", "delay", "measure"],
+            gates=[],
+            local=True,
+            simulator=True,
+            conditional=False,
+            open_pulse=False,
+            memory=False,
+            max_shots=int(1e6),
+            coupling_map=None,
         )
 
         self._t1 = t1

From b967814dae4505d243d6fbd1bd59383358ea032a Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Mon, 5 Apr 2021 16:36:38 +0300
Subject: [PATCH 30/59] result unit in microseconds if unit is dt

---
 .../characterization/t1_experiment.py         | 26 +++++++++++++--
 test/test_t1.py                               | 33 ++++++++++---------
 2 files changed, 40 insertions(+), 19 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 5d9658b7b0..6293cc14b8 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -45,13 +45,22 @@ def _run_analysis(
             The analysis result with the estimated T1
         """
 
+        circuit_unit = experiment_data._data[0]["metadata"]["unit"]
+        dt_factor_in_sec = experiment_data._data[0]["metadata"]["dt_factor_in_sec"]
+        if dt_factor_in_sec is None:
+            dt_factor_in_microsec = 1
+            result_unit = circuit_unit
+        else:
+            dt_factor_in_microsec = dt_factor_in_sec * 1000000
+            result_unit = "us"
+
         size = len(experiment_data._data)
         delays = np.zeros(size, dtype=float)
         means = np.zeros(size, dtype=float)
         stddevs = np.zeros(size, dtype=float)
 
         for i, circ in enumerate(experiment_data._data):
-            delays[i] = circ["metadata"]["delay"]
+            delays[i] = circ["metadata"]["delay"] * dt_factor_in_microsec
             count0 = circ["counts"].get("0", 0)
             count1 = circ["counts"].get("1", 0)
             shots = count0 + count1
@@ -64,6 +73,8 @@ def _run_analysis(
 
         if t1_guess is None:
             t1_guess = np.mean(delays)
+        else:
+            t1_guess = t1_guess * dt_factor_in_microsec
         if offset_guess is None:
             offset_guess = means[-1]
         if amplitude_guess is None:
@@ -81,7 +92,7 @@ def _run_analysis(
             {
                 "value": fit_out[1],
                 "stderr": fit_err[1],
-                "unit": experiment_data._data[0]["metadata"]["unit"],
+                "unit": result_unit,
                 "label": "T1",
                 "fit": {
                     "params": fit_out,
@@ -114,7 +125,7 @@ class T1Experiment(BaseExperiment):
 
     __analysis_class__ = T1Analysis
 
-    def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str = "dt"):
+    def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str = "us"):
         """
         Initialize the T1 experiment class
 
@@ -146,6 +157,14 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
             The experiment circuits
         """
 
+        if self._unit == "dt":
+            try:
+                dt_factor_in_sec = getattr( backend.configuration(), "dt")
+            except AttributeError:
+                raise AttributeError("Dt parameter is missing in backend configuration")
+        else:
+            dt_factor_in_sec = None
+
         circuits = []
 
         for delay in self._delays:
@@ -162,6 +181,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 "qubit": self.physical_qubits[0],
                 "delay": delay,
                 "unit": self._unit,
+                "dt_factor_in_sec": dt_factor_in_sec
             }
 
             circuits.append(circ)
diff --git a/test/test_t1.py b/test/test_t1.py
index 48092f17e7..8c715ec159 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -18,7 +18,7 @@
 import unittest
 import numpy as np
 from qiskit.providers import BaseBackend
-from qiskit.providers.models import BackendConfiguration
+from qiskit.providers.models import QasmBackendConfiguration
 from qiskit.result import Result
 from qiskit_experiments import ExperimentData
 from qiskit_experiments.composite import ParallelExperiment
@@ -30,12 +30,12 @@ class T1Backend(BaseBackend):
     A simple and primitive backend, to be run by the T1 tests
     """
 
-    def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None):
+    def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, dt_factor_in_microsec=1e6):
         """
         Initialize the T1 backend
         """
 
-        configuration = BackendConfiguration(
+        configuration = QasmBackendConfiguration(
             backend_name="t1_simulator",
             backend_version="0",
             n_qubits=int(1e6),
@@ -48,12 +48,14 @@ def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None):
             memory=False,
             max_shots=int(1e6),
             coupling_map=None,
+            dt=dt_factor_in_microsec * 1000
         )
 
         self._t1 = t1
         self._initial_prob1 = initial_prob1
         self._readout0to1 = readout0to1
         self._readout1to0 = readout1to0
+        self._dt_factor_in_microsec = dt_factor_in_microsec
         super().__init__(configuration)
 
     #pylint: disable = arguments-differ
@@ -100,8 +102,8 @@ def run(self, qobj):
                     if op.name == "x":
                         prob1[qubit] = 1 - prob1[qubit]
                     if op.name == "delay":
-                        if self._t1[qubit] is not None:
-                            prob1[qubit] = prob1[qubit] * np.exp(-op.params[0] / self._t1[qubit])
+                        delay = op.params[0] * self._dt_factor_in_microsec
+                        prob1[qubit] = prob1[qubit] * np.exp(-delay / self._t1[qubit])
                     if op.name == "measure":
                         meas_res = np.random.binomial(
                             1, prob1[qubit] * (1 - ro10[qubit]) + (1 - prob1[qubit]) * ro01[qubit]
@@ -140,18 +142,21 @@ def test_t1_end2end(self):
         Test T1 experiment using a simulator.
         """
 
+        dt_factor_in_microsec = 0.0002
+
         t1 = 25
+        backend = T1Backend([t1], initial_prob1=[0.02], readout0to1=[0.02], readout1to0=[0.02], dt_factor_in_microsec=dt_factor_in_microsec)
 
-        delays = list(range(1, 40, 3))
+        delays = list(range(int(1/dt_factor_in_microsec), int(40/dt_factor_in_microsec), int(3/dt_factor_in_microsec)))
 
         # dummy numbers to avoid exception triggerring
-        instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
+        instruction_durations = [("measure", [0], 3/dt_factor_in_microsec, "dt"), ("x", [0], 3/dt_factor_in_microsec, "dt")]
 
-        exp = T1Experiment(0, delays)
+        exp = T1Experiment(0, delays, unit="dt")
         res = exp.run(
-            T1Backend([t1], initial_prob1=[0.02], readout0to1=[0.02], readout1to0=[0.02]),
+            backend,
             amplitude_guess=1,
-            t1_guess=t1,
+            t1_guess=t1 / dt_factor_in_microsec,
             offset_guess=0,
             instruction_durations=instruction_durations,
             shots=10000,
@@ -166,18 +171,13 @@ def test_t1_parallel(self):
         """
 
         t1 = [25, 15]
-
         delays = list(range(1, 40, 3))
 
-        # dummy numbers to avoid exception triggerring
-        instruction_durations = [("measure", [0], 3, "dt"), ("x", [0], 3, "dt")]
-
         exp0 = T1Experiment(0, delays)
         exp2 = T1Experiment(2, delays)
         par_exp = ParallelExperiment([exp0, exp2])
         res = par_exp.run(
             T1Backend([t1[0], None, t1[1]]),
-            instruction_durations=instruction_durations,
             shots=10000,
         )
 
@@ -202,7 +202,8 @@ def test_t1_analysis(self):
                         "delay": 3 * i + 1,
                         "experiment_type": "T1Experiment",
                         "qubit": 0,
-                        "unit": "dt",
+                        "unit": "us",
+                        "dt_factor_in_sec": None,
                     },
                 }
             )

From 17005fe13e201dd9248011c8575b672a2f10c326 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 10:39:44 +0300
Subject: [PATCH 31/59] a small change to a test

---
 test/test_t1.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_t1.py b/test/test_t1.py
index 8c715ec159..e8b9d689e4 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -202,7 +202,7 @@ def test_t1_analysis(self):
                         "delay": 3 * i + 1,
                         "experiment_type": "T1Experiment",
                         "qubit": 0,
-                        "unit": "us",
+                        "unit": "ns",
                         "dt_factor_in_sec": None,
                     },
                 }

From d67fa9dfd7cd8f0ddf3f0cca8a6328c7d5f37509 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 10:49:17 +0300
Subject: [PATCH 32/59] T1Analisys._fit_quality

---
 qiskit_experiments/characterization/t1_experiment.py | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 6293cc14b8..19133c317a 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -101,9 +101,14 @@ def _run_analysis(
                     "chisq": chisq,
                     "cov": fit_cov,
                 },
+                "quality": self._fit_quality(fit_out, fit_err, chisq)
             }
         )
 
+        return analysis_result, None
+
+    @staticmethod
+    def _fit_quality(fit_out, fit_err, chisq):
         #pylint: disable = too-many-boolean-expressions
         if (
             abs(fit_out[0] - 1.0) < 0.1
@@ -113,11 +118,9 @@ def _run_analysis(
             and (fit_err[1] is None or fit_err[1] < fit_out[1])
             and (fit_err[2] is None or fit_err[2] < 0.1)
         ):
-            analysis_result["quality"] = "computer_good"
+            return "computer_good"
         else:
-            analysis_result["quality"] = "computer_bad"
-
-        return analysis_result, None
+            return "computer_bad"
 
 
 class T1Experiment(BaseExperiment):

From c579517124138faa24f676c0092c0b7e32ae1f76 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 10:53:56 +0300
Subject: [PATCH 33/59] removed unnecessary pylint disable

---
 qiskit_experiments/characterization/t1_experiment.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 19133c317a..24ad31238d 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -178,7 +178,6 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
             circ.barrier(0)
             circ.measure(0, 0)
 
-            # pylint: disable = eval-used
             circ.metadata = {
                 "experiment_type": self._type,
                 "qubit": self.physical_qubits[0],

From 5d9b2966ea7128d2e5b3a41a08616befdb582f69 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 11:22:53 +0300
Subject: [PATCH 34/59] test_t1_metadata

---
 test/test_t1.py | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/test/test_t1.py b/test/test_t1.py
index e8b9d689e4..2e57358e83 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -212,6 +212,28 @@ def test_t1_analysis(self):
         self.assertEqual(res["quality"], "computer_good")
         self.assertAlmostEqual(res["value"], 25, delta=3)
 
+    def test_t1_metadata(self):
+        """
+        Test the circuits metadata
+        """
+
+        t1 = 25
+        delays = list(range(1, 40, 3))
+        exp = T1Experiment(0, delays, unit="ms")
+        circs = exp.circuits()
+
+        self.assertEqual(len(circs), len(delays))
+        
+        for delay, circ in zip(delays, circs):
+            self.assertEqual(circ.metadata,
+                             {
+                                 "experiment_type": "T1Experiment",
+                                 "qubit": 0,
+                                 "delay": delay,
+                                 "unit": "ms",
+                                 "dt_factor_in_sec": None
+                                 })
+        
 
 if __name__ == "__main__":
     unittest.main()

From e1a9da63b933044cfcdde876ba88650087c6471b Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 13:31:27 +0300
Subject: [PATCH 35/59] allow the user to set the experiment type

---
 qiskit_experiments/characterization/t1_experiment.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 24ad31238d..58b9d39ab4 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -128,15 +128,15 @@ class T1Experiment(BaseExperiment):
 
     __analysis_class__ = T1Analysis
 
-    def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str = "us"):
+    def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: Optional[str] = "us", experiment_type: Optional[str] = None):
         """
         Initialize the T1 experiment class
 
         Args:
             qubit: the qubit whose T1 is to be estimated
             delays: delay times of the experiments
-            unit: unit of the duration. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
-                Default is ``dt``, i.e. integer time unit depending on the target backend.
+            unit:Optional, unit of the duration. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
+            experiment_type: Optional, the experiment type string.
 
         Raises:
             ValueError: if the number of delays is smaller than 3
@@ -146,7 +146,7 @@ def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: str =
 
         self._delays = delays
         self._unit = unit
-        super().__init__([qubit], type(self).__name__)
+        super().__init__([qubit], experiment_type)
 
     # pylint: disable=arguments-differ
     def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:

From eea32e5e2c49a2f0eb91c87b7f40ec79ef5708aa Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 13:51:59 +0300
Subject: [PATCH 36/59] test_t1_low_quality

---
 test/test_t1.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/test/test_t1.py b/test/test_t1.py
index 2e57358e83..0e6a6d107b 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -233,6 +233,30 @@ def test_t1_metadata(self):
                                  "unit": "ms",
                                  "dt_factor_in_sec": None
                                  })
+
+    def test_t1_low_quality(self):
+        """
+        A test where the fit's quality will be low
+        """
+
+        data = ExperimentData(None)
+
+        for i in range(3):
+            data._data.append(
+                {
+                    "counts": {"0": 10, "1": 10},
+                    "metadata": {
+                        "delay": i,
+                        "experiment_type": "T1Experiment",
+                        "qubit": 0,
+                        "unit": "ns",
+                        "dt_factor_in_sec": None,
+                    },
+                }
+            )
+
+        res = T1Analysis()._run_analysis(data)[0]
+        self.assertEqual(res["quality"], "computer_bad")
         
 
 if __name__ == "__main__":

From bd7bf7d56c5407d9730637df7725d24bb0e1476a Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 13:58:45 +0300
Subject: [PATCH 37/59] black and lint

---
 .../characterization/t1_experiment.py         | 19 +++++--
 test/test_t1.py                               | 52 +++++++++++++------
 2 files changed, 49 insertions(+), 22 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 58b9d39ab4..e817ca2514 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -101,7 +101,7 @@ def _run_analysis(
                     "chisq": chisq,
                     "cov": fit_cov,
                 },
-                "quality": self._fit_quality(fit_out, fit_err, chisq)
+                "quality": self._fit_quality(fit_out, fit_err, chisq),
             }
         )
 
@@ -109,7 +109,7 @@ def _run_analysis(
 
     @staticmethod
     def _fit_quality(fit_out, fit_err, chisq):
-        #pylint: disable = too-many-boolean-expressions
+        # pylint: disable = too-many-boolean-expressions
         if (
             abs(fit_out[0] - 1.0) < 0.1
             and abs(fit_out[2]) < 0.1
@@ -128,7 +128,13 @@ class T1Experiment(BaseExperiment):
 
     __analysis_class__ = T1Analysis
 
-    def __init__(self, qubit: int, delays: Union[List[float], np.array], unit: Optional[str] = "us", experiment_type: Optional[str] = None):
+    def __init__(
+        self,
+        qubit: int,
+        delays: Union[List[float], np.array],
+        unit: Optional[str] = "us",
+        experiment_type: Optional[str] = None,
+    ):
         """
         Initialize the T1 experiment class
 
@@ -158,11 +164,14 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
 
         Returns:
             The experiment circuits
+
+        Raises:
+            AttributeError: if unit is dt but dt parameter is missing in the backend configuration
         """
 
         if self._unit == "dt":
             try:
-                dt_factor_in_sec = getattr( backend.configuration(), "dt")
+                dt_factor_in_sec = getattr(backend.configuration(), "dt")
             except AttributeError:
                 raise AttributeError("Dt parameter is missing in backend configuration")
         else:
@@ -183,7 +192,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 "qubit": self.physical_qubits[0],
                 "delay": delay,
                 "unit": self._unit,
-                "dt_factor_in_sec": dt_factor_in_sec
+                "dt_factor_in_sec": dt_factor_in_sec,
             }
 
             circuits.append(circ)
diff --git a/test/test_t1.py b/test/test_t1.py
index 0e6a6d107b..1a6ed06964 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -30,7 +30,9 @@ class T1Backend(BaseBackend):
     A simple and primitive backend, to be run by the T1 tests
     """
 
-    def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, dt_factor_in_microsec=1e6):
+    def __init__(
+        self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, dt_factor_in_microsec=1e6
+    ):
         """
         Initialize the T1 backend
         """
@@ -48,7 +50,7 @@ def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, d
             memory=False,
             max_shots=int(1e6),
             coupling_map=None,
-            dt=dt_factor_in_microsec * 1000
+            dt=dt_factor_in_microsec * 1000,
         )
 
         self._t1 = t1
@@ -58,7 +60,7 @@ def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, d
         self._dt_factor_in_microsec = dt_factor_in_microsec
         super().__init__(configuration)
 
-    #pylint: disable = arguments-differ
+    # pylint: disable = arguments-differ
     def run(self, qobj):
         """
         Run the T1 backend
@@ -145,12 +147,27 @@ def test_t1_end2end(self):
         dt_factor_in_microsec = 0.0002
 
         t1 = 25
-        backend = T1Backend([t1], initial_prob1=[0.02], readout0to1=[0.02], readout1to0=[0.02], dt_factor_in_microsec=dt_factor_in_microsec)
+        backend = T1Backend(
+            [t1],
+            initial_prob1=[0.02],
+            readout0to1=[0.02],
+            readout1to0=[0.02],
+            dt_factor_in_microsec=dt_factor_in_microsec,
+        )
 
-        delays = list(range(int(1/dt_factor_in_microsec), int(40/dt_factor_in_microsec), int(3/dt_factor_in_microsec)))
+        delays = list(
+            range(
+                int(1 / dt_factor_in_microsec),
+                int(40 / dt_factor_in_microsec),
+                int(3 / dt_factor_in_microsec),
+            )
+        )
 
         # dummy numbers to avoid exception triggerring
-        instruction_durations = [("measure", [0], 3/dt_factor_in_microsec, "dt"), ("x", [0], 3/dt_factor_in_microsec, "dt")]
+        instruction_durations = [
+            ("measure", [0], 3 / dt_factor_in_microsec, "dt"),
+            ("x", [0], 3 / dt_factor_in_microsec, "dt"),
+        ]
 
         exp = T1Experiment(0, delays, unit="dt")
         res = exp.run(
@@ -217,22 +234,23 @@ def test_t1_metadata(self):
         Test the circuits metadata
         """
 
-        t1 = 25
         delays = list(range(1, 40, 3))
         exp = T1Experiment(0, delays, unit="ms")
         circs = exp.circuits()
 
         self.assertEqual(len(circs), len(delays))
-        
+
         for delay, circ in zip(delays, circs):
-            self.assertEqual(circ.metadata,
-                             {
-                                 "experiment_type": "T1Experiment",
-                                 "qubit": 0,
-                                 "delay": delay,
-                                 "unit": "ms",
-                                 "dt_factor_in_sec": None
-                                 })
+            self.assertEqual(
+                circ.metadata,
+                {
+                    "experiment_type": "T1Experiment",
+                    "qubit": 0,
+                    "delay": delay,
+                    "unit": "ms",
+                    "dt_factor_in_sec": None,
+                },
+            )
 
     def test_t1_low_quality(self):
         """
@@ -257,7 +275,7 @@ def test_t1_low_quality(self):
 
         res = T1Analysis()._run_analysis(data)[0]
         self.assertEqual(res["quality"], "computer_bad")
-        
+
 
 if __name__ == "__main__":
     unittest.main()

From 7eff4b41d4f809a470bb1d7fc846f8ed4949f272 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Tue, 6 Apr 2021 16:25:15 +0300
Subject: [PATCH 38/59] more black and lint

---
 qiskit_experiments/characterization/analysis_functions.py | 1 +
 qiskit_experiments/characterization/t1_experiment.py      | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
index 5aed02f7ca..113c4c0abf 100644
--- a/qiskit_experiments/characterization/analysis_functions.py
+++ b/qiskit_experiments/characterization/analysis_functions.py
@@ -44,6 +44,7 @@ def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
         matrix: the covariance matrix
         float: chi-square
     """
+    # pylint: disable=unbalanced-tuple-unpacking
     fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
 
     chisq = 0
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index e817ca2514..889e3e8b43 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -172,8 +172,8 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
         if self._unit == "dt":
             try:
                 dt_factor_in_sec = getattr(backend.configuration(), "dt")
-            except AttributeError:
-                raise AttributeError("Dt parameter is missing in backend configuration")
+            except AttributeError as no_dt:
+                raise AttributeError("Dt parameter is missing in backend configuration") from no_dt
         else:
             dt_factor_in_sec = None
 

From 6000cf89efc13222a9676777711d4a4d3a18ebfc Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 8 Apr 2021 09:45:39 +0300
Subject: [PATCH 39/59] added bounds option to t1

---
 .../characterization/t1_experiment.py         | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 889e3e8b43..54784ed095 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -29,7 +29,15 @@ class T1Analysis(BaseAnalysis):
 
     # pylint: disable=arguments-differ, unused-argument
     def _run_analysis(
-        self, experiment_data, t1_guess=None, amplitude_guess=None, offset_guess=None, **kwargs
+        self,
+        experiment_data,
+        t1_guess=None,
+        amplitude_guess=None,
+        offset_guess=None,
+        t1_bounds=None,
+        amplitude_bounds=None,
+        offset_bounds=None,
+        **kwargs,
     ) -> Tuple[AnalysisResult, None]:
         """
         Calculate T1
@@ -39,6 +47,9 @@ def _run_analysis(
             t1_guess (float): Optional, an initial guess of T1
             amplitude_guess (float): Optional, an initial guess of the coefficient of the exponent
             offset_guess (float): Optional, an initial guess of the offset
+            t1_bounds (list of two floats): Optional, lower bound and uper bound to T1
+            amplitude_bounds (list of two floats): Optional, lower bound and uper bound to the amplitude
+            offset_bounds (list of two floats): Optional, lower bound and uper bound to the offset
             kwargs: Trailing unused function parameters
 
         Returns:
@@ -79,6 +90,12 @@ def _run_analysis(
             offset_guess = means[-1]
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
+        if t1_bounds is None:
+            t1_bounds = [-np.inf, np.inf]
+        if amplitude_bounds is None:
+            amplitude_bounds = [0, 1]
+        if offset_bounds is None:
+            offset_bounds = [0, 1]
 
         fit_out, fit_err, fit_cov, chisq = curve_fit_wrapper(
             exp_fit_fun,

From cf7bfbbf53ef0aba0f5dcc6373310c614b9f3424 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Thu, 8 Apr 2021 16:30:00 +0300
Subject: [PATCH 40/59] a small fix

---
 qiskit_experiments/characterization/t1_experiment.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 54784ed095..7f39d4575d 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -91,7 +91,7 @@ def _run_analysis(
         if amplitude_guess is None:
             amplitude_guess = means[0] - offset_guess
         if t1_bounds is None:
-            t1_bounds = [-np.inf, np.inf]
+            t1_bounds = [0, np.inf]
         if amplitude_bounds is None:
             amplitude_bounds = [0, 1]
         if offset_bounds is None:

From 9581589ed03004ddec55d9d1a5e91d16c78d80a1 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Sun, 11 Apr 2021 09:19:14 +0300
Subject: [PATCH 41/59] no dt info in metadata if unit is not dt

---
 qiskit_experiments/characterization/t1_experiment.py | 10 +++++-----
 test/test_t1.py                                      |  1 -
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 7f39d4575d..a34b0f78c7 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -57,7 +57,7 @@ def _run_analysis(
         """
 
         circuit_unit = experiment_data._data[0]["metadata"]["unit"]
-        dt_factor_in_sec = experiment_data._data[0]["metadata"]["dt_factor_in_sec"]
+        dt_factor_in_sec = experiment_data._data[0]["metadata"].get("dt_factor_in_sec", None)
         if dt_factor_in_sec is None:
             dt_factor_in_microsec = 1
             result_unit = circuit_unit
@@ -191,8 +191,6 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 dt_factor_in_sec = getattr(backend.configuration(), "dt")
             except AttributeError as no_dt:
                 raise AttributeError("Dt parameter is missing in backend configuration") from no_dt
-        else:
-            dt_factor_in_sec = None
 
         circuits = []
 
@@ -209,9 +207,11 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 "qubit": self.physical_qubits[0],
                 "delay": delay,
                 "unit": self._unit,
-                "dt_factor_in_sec": dt_factor_in_sec,
             }
-
+                
+            if self._unit == "dt":
+                circ.metadata["dt_factor_in_sec"] = dt_factor_in_sec
+            
             circuits.append(circ)
 
         return circuits
diff --git a/test/test_t1.py b/test/test_t1.py
index 1a6ed06964..0c54f1975c 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -248,7 +248,6 @@ def test_t1_metadata(self):
                     "qubit": 0,
                     "delay": delay,
                     "unit": "ms",
-                    "dt_factor_in_sec": None,
                 },
             )
 

From f20ac7b9bc184ab84dc11f1006ae086eee1a9ea5 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Sun, 11 Apr 2021 09:24:56 +0300
Subject: [PATCH 42/59] fix docstring of exp_fit_fun

---
 .../characterization/analysis_functions.py               | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
index 113c4c0abf..af92d3abc2 100644
--- a/qiskit_experiments/characterization/analysis_functions.py
+++ b/qiskit_experiments/characterization/analysis_functions.py
@@ -20,6 +20,15 @@
 def exp_fit_fun(x, a, tau, c):
     """
     Exponential fit function
+
+    Args:
+        x (float or array): a function parameter
+        a (float or array): a function parameter (exponent amplitude)
+        tau (float or array): a function parameter (exponential decrease rate)
+        c (float or array): a function parameter (exponent offset)
+
+    Returns:
+         a * np.exp(-x / tau) + c
     """
     return a * np.exp(-x / tau) + c
 

From edebf3e666c9d27fd0dd64639fe86f1ecda24ef5 Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Sun, 11 Apr 2021 10:02:10 +0300
Subject: [PATCH 43/59] added generate_delays

---
 qiskit_experiments/characterization/t1_experiment.py | 4 ++++
 test/test_t1.py                                      | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index a34b0f78c7..007c1fd893 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -215,3 +215,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
             circuits.append(circ)
 
         return circuits
+
+    @staticmethod
+    def generate_delays(t1_estimate, num_of_points):
+        return np.geomspace(3, 7*t1_estimate, num_of_points)
diff --git a/test/test_t1.py b/test/test_t1.py
index 0c54f1975c..400d92e190 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -275,6 +275,12 @@ def test_t1_low_quality(self):
         res = T1Analysis()._run_analysis(data)[0]
         self.assertEqual(res["quality"], "computer_bad")
 
+    def test_generate_delays(self):
+        delays = T1Experiment.generate_delays(25, 30)
+        self.assertEqual(len(delays), 30)
+        self.assertEqual(delays[0], 3)
+        self.assertEqual(delays[-1], 175)
+
 
 if __name__ == "__main__":
     unittest.main()

From 70b3411a61f454cb3800947350f2e33dde2177ab Mon Sep 17 00:00:00 2001
From: yaelbh <yaelbh@il.ibm.com>
Date: Sun, 11 Apr 2021 10:07:21 +0300
Subject: [PATCH 44/59] black and lint

---
 .../characterization/analysis_functions.py       |  2 +-
 .../characterization/t1_experiment.py            | 16 +++++++++++++---
 test/test_t1.py                                  |  3 +++
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
index af92d3abc2..20ec3a13a5 100644
--- a/qiskit_experiments/characterization/analysis_functions.py
+++ b/qiskit_experiments/characterization/analysis_functions.py
@@ -28,7 +28,7 @@ def exp_fit_fun(x, a, tau, c):
         c (float or array): a function parameter (exponent offset)
 
     Returns:
-         a * np.exp(-x / tau) + c
+        float or array: a * np.exp(-x / tau) + c
     """
     return a * np.exp(-x / tau) + c
 
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 007c1fd893..f4625e0b18 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -208,14 +208,24 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
                 "delay": delay,
                 "unit": self._unit,
             }
-                
+
             if self._unit == "dt":
                 circ.metadata["dt_factor_in_sec"] = dt_factor_in_sec
-            
+
             circuits.append(circ)
 
         return circuits
 
     @staticmethod
     def generate_delays(t1_estimate, num_of_points):
-        return np.geomspace(3, 7*t1_estimate, num_of_points)
+        """
+        Generate delays from an estimate of T1
+
+        Args:
+            t1_estimate (float): estimate of T1
+            num_of_points (float): number of delays to generate
+
+        Returns:
+            float: delays, distributed in a logarithmic scale
+        """
+        return np.geomspace(3, 7 * t1_estimate, num_of_points)
diff --git a/test/test_t1.py b/test/test_t1.py
index 400d92e190..224451f527 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -276,6 +276,9 @@ def test_t1_low_quality(self):
         self.assertEqual(res["quality"], "computer_bad")
 
     def test_generate_delays(self):
+        """
+        Test the static method T1Experiment.generate_delays
+        """
         delays = T1Experiment.generate_delays(25, 30)
         self.assertEqual(len(delays), 30)
         self.assertEqual(delays[0], 3)

From 77c54bd1f126da69fdda7eb33321e775448bd184 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Sun, 18 Apr 2021 16:53:52 +0300
Subject: [PATCH 45/59] typo fix

---
 qiskit_experiments/characterization/t1_experiment.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index f4625e0b18..a96533f40a 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -47,9 +47,9 @@ def _run_analysis(
             t1_guess (float): Optional, an initial guess of T1
             amplitude_guess (float): Optional, an initial guess of the coefficient of the exponent
             offset_guess (float): Optional, an initial guess of the offset
-            t1_bounds (list of two floats): Optional, lower bound and uper bound to T1
-            amplitude_bounds (list of two floats): Optional, lower bound and uper bound to the amplitude
-            offset_bounds (list of two floats): Optional, lower bound and uper bound to the offset
+            t1_bounds (list of two floats): Optional, lower bound and upper bound to T1
+            amplitude_bounds (list of two floats): Optional, lower bound and upper bound to the amplitude
+            offset_bounds (list of two floats): Optional, lower bound and upper bound to the offset
             kwargs: Trailing unused function parameters
 
         Returns:

From 65fc2697e6878f5618c23de8601003926e106022 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Sun, 18 Apr 2021 17:14:59 +0300
Subject: [PATCH 46/59] removed generate_delays

---
 .../characterization/t1_experiment.py              | 14 --------------
 test/test_t1.py                                    |  9 ---------
 2 files changed, 23 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index a96533f40a..55ff4ee9c1 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -215,17 +215,3 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
             circuits.append(circ)
 
         return circuits
-
-    @staticmethod
-    def generate_delays(t1_estimate, num_of_points):
-        """
-        Generate delays from an estimate of T1
-
-        Args:
-            t1_estimate (float): estimate of T1
-            num_of_points (float): number of delays to generate
-
-        Returns:
-            float: delays, distributed in a logarithmic scale
-        """
-        return np.geomspace(3, 7 * t1_estimate, num_of_points)
diff --git a/test/test_t1.py b/test/test_t1.py
index 224451f527..0c54f1975c 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -275,15 +275,6 @@ def test_t1_low_quality(self):
         res = T1Analysis()._run_analysis(data)[0]
         self.assertEqual(res["quality"], "computer_bad")
 
-    def test_generate_delays(self):
-        """
-        Test the static method T1Experiment.generate_delays
-        """
-        delays = T1Experiment.generate_delays(25, 30)
-        self.assertEqual(len(delays), 30)
-        self.assertEqual(delays[0], 3)
-        self.assertEqual(delays[-1], 175)
-
 
 if __name__ == "__main__":
     unittest.main()

From bfb1e3cfd36b3e5c60478c69b9e855cf9a59f24d Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Wed, 21 Apr 2021 20:41:11 +0300
Subject: [PATCH 47/59] make t1 use the helper functions

---
 .../characterization/analysis_functions.py    | 66 -------------------
 .../characterization/t1_experiment.py         | 63 +++++++-----------
 test/test_t1.py                               |  8 +--
 3 files changed, 26 insertions(+), 111 deletions(-)
 delete mode 100644 qiskit_experiments/characterization/analysis_functions.py

diff --git a/qiskit_experiments/characterization/analysis_functions.py b/qiskit_experiments/characterization/analysis_functions.py
deleted file mode 100644
index 20ec3a13a5..0000000000
--- a/qiskit_experiments/characterization/analysis_functions.py
+++ /dev/null
@@ -1,66 +0,0 @@
-# This code is part of Qiskit.
-#
-# (C) Copyright IBM 2021.
-#
-# This code is licensed under the Apache License, Version 2.0. You may
-# obtain a copy of this license in the LICENSE.txt file in the root directory
-# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
-#
-# Any modifications or derivative works of this code must retain this
-# copyright notice, and modified files need to carry a notice indicating
-# that they have been altered from the originals.
-"""
-Functions for fitting parameters.
-"""
-
-import numpy as np
-from scipy.optimize import curve_fit
-
-
-def exp_fit_fun(x, a, tau, c):
-    """
-    Exponential fit function
-
-    Args:
-        x (float or array): a function parameter
-        a (float or array): a function parameter (exponent amplitude)
-        tau (float or array): a function parameter (exponential decrease rate)
-        c (float or array): a function parameter (exponent offset)
-
-    Returns:
-        float or array: a * np.exp(-x / tau) + c
-    """
-    return a * np.exp(-x / tau) + c
-
-
-# pylint: disable = invalid-name
-def curve_fit_wrapper(f, xdata, ydata, sigma, **kwargs):
-    """
-    A wrapper to curve_fit that calculates and returns fit_err
-    (square root of the diagonal of the covariance matrix) and chi square.
-
-    Args:
-        f (callable): see documentation of curve_fit in scipy.optimize
-        xdata (list): see documentation of curve_fit in scipy.optimize
-        ydata (list): see documentation of curve_fit in scipy.optimize
-        sigma (list): see documentation of curve_fit in scipy.optimize
-        kwargs: additional paramters to be passed to curve_fit
-
-    Returns:
-        list: fitted parameters
-        list: error on fitted parameters
-              (square root of the diagonal of the covariance matrix)
-        matrix: the covariance matrix
-        float: chi-square
-    """
-    # pylint: disable=unbalanced-tuple-unpacking
-    fit_out, fit_cov = curve_fit(f, xdata, ydata, sigma=sigma, **kwargs)
-
-    chisq = 0
-    for x, y, sig in zip(xdata, ydata, sigma):
-        chisq += (f(x, *fit_out) - y) ** 2 / sig ** 2
-    chisq /= len(xdata)
-
-    fit_err = np.sqrt(np.diag(fit_cov))
-
-    return fit_out, fit_err, fit_cov, chisq
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 55ff4ee9c1..84f2bd7f7e 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -20,8 +20,9 @@
 
 from qiskit_experiments.base_experiment import BaseExperiment
 from qiskit_experiments.base_analysis import BaseAnalysis
+from qiskit_experiments.analysis.curve_fitting import process_curve_data, curve_fit
+from qiskit_experiments.analysis.data_processing import level2_probability
 from qiskit_experiments import AnalysisResult
-from .analysis_functions import exp_fit_fun, curve_fit_wrapper
 
 
 class T1Analysis(BaseAnalysis):
@@ -65,31 +66,17 @@ def _run_analysis(
             dt_factor_in_microsec = dt_factor_in_sec * 1000000
             result_unit = "us"
 
-        size = len(experiment_data._data)
-        delays = np.zeros(size, dtype=float)
-        means = np.zeros(size, dtype=float)
-        stddevs = np.zeros(size, dtype=float)
-
-        for i, circ in enumerate(experiment_data._data):
-            delays[i] = circ["metadata"]["delay"] * dt_factor_in_microsec
-            count0 = circ["counts"].get("0", 0)
-            count1 = circ["counts"].get("1", 0)
-            shots = count0 + count1
-            means[i] = count1 / shots
-            stddevs[i] = np.sqrt(means[i] * (1 - means[i]) / shots)
-            # problem for the fitter if one of the std points is
-            # exactly zero
-            if stddevs[i] == 0:
-                stddevs[i] = 1e-4
+        xdata, ydata, sigma = process_curve_data(experiment_data._data, lambda datum: level2_probability(datum, '1'))
+        xdata *= dt_factor_in_microsec
 
         if t1_guess is None:
-            t1_guess = np.mean(delays)
+            t1_guess = np.mean(xdata)
         else:
             t1_guess = t1_guess * dt_factor_in_microsec
         if offset_guess is None:
-            offset_guess = means[-1]
+            offset_guess = ydata[-1]
         if amplitude_guess is None:
-            amplitude_guess = means[0] - offset_guess
+            amplitude_guess = ydata[0] - offset_guess
         if t1_bounds is None:
             t1_bounds = [0, np.inf]
         if amplitude_bounds is None:
@@ -97,40 +84,34 @@ def _run_analysis(
         if offset_bounds is None:
             offset_bounds = [0, 1]
 
-        fit_out, fit_err, fit_cov, chisq = curve_fit_wrapper(
-            exp_fit_fun,
-            delays,
-            means,
-            stddevs,
-            p0=[amplitude_guess, t1_guess, offset_guess],
+        fit_result = curve_fit(
+            lambda x, a, tau, c: a * np.exp(-x / tau) + c,
+            xdata,
+            ydata,
+            [amplitude_guess, t1_guess, offset_guess],
+            sigma,
+            tuple([amp_bnd, t1_bnd, offset_bnd] for amp_bnd, t1_bnd, offset_bnd in zip(amplitude_bounds, t1_bounds, offset_bounds))
         )
 
         analysis_result = AnalysisResult(
             {
-                "value": fit_out[1],
-                "stderr": fit_err[1],
+                "value": fit_result["popt"][1],
+                "stderr": fit_result["popt_err"][1],
                 "unit": result_unit,
                 "label": "T1",
-                "fit": {
-                    "params": fit_out,
-                    "stderr": fit_err,
-                    "labels": ["amplitude", "T1", "offset"],
-                    "chisq": chisq,
-                    "cov": fit_cov,
-                },
-                "quality": self._fit_quality(fit_out, fit_err, chisq),
-            }
-        )
+                "fit": fit_result,
+                "quality": self._fit_quality(fit_result["popt"], fit_result["popt_err"], fit_result["reduced_chisq"]),
+            })
 
         return analysis_result, None
 
     @staticmethod
-    def _fit_quality(fit_out, fit_err, chisq):
+    def _fit_quality(fit_out, fit_err, reduced_chisq):
         # pylint: disable = too-many-boolean-expressions
         if (
             abs(fit_out[0] - 1.0) < 0.1
             and abs(fit_out[2]) < 0.1
-            and chisq < 3
+            and reduced_chisq < 3
             and (fit_err[0] is None or fit_err[0] < 0.1)
             and (fit_err[1] is None or fit_err[1] < fit_out[1])
             and (fit_err[2] is None or fit_err[2] < 0.1)
@@ -205,7 +186,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
             circ.metadata = {
                 "experiment_type": self._type,
                 "qubit": self.physical_qubits[0],
-                "delay": delay,
+                "xval": delay,
                 "unit": self._unit,
             }
 
diff --git a/test/test_t1.py b/test/test_t1.py
index 0c54f1975c..7619a7a466 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -216,7 +216,7 @@ def test_t1_analysis(self):
                 {
                     "counts": {"0": count0, "1": 10000 - count0},
                     "metadata": {
-                        "delay": 3 * i + 1,
+                        "xval": 3 * i + 1,
                         "experiment_type": "T1Experiment",
                         "qubit": 0,
                         "unit": "ns",
@@ -246,7 +246,7 @@ def test_t1_metadata(self):
                 {
                     "experiment_type": "T1Experiment",
                     "qubit": 0,
-                    "delay": delay,
+                    "xval": delay,
                     "unit": "ms",
                 },
             )
@@ -258,12 +258,12 @@ def test_t1_low_quality(self):
 
         data = ExperimentData(None)
 
-        for i in range(3):
+        for i in range(10):
             data._data.append(
                 {
                     "counts": {"0": 10, "1": 10},
                     "metadata": {
-                        "delay": i,
+                        "xval": i,
                         "experiment_type": "T1Experiment",
                         "qubit": 0,
                         "unit": "ns",

From 945fa3f37bf4571ff01926ae721c74ba3861145f Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Wed, 21 Apr 2021 20:43:01 +0300
Subject: [PATCH 48/59] black

---
 .../characterization/t1_experiment.py            | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 84f2bd7f7e..eb126cbd73 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -66,7 +66,9 @@ def _run_analysis(
             dt_factor_in_microsec = dt_factor_in_sec * 1000000
             result_unit = "us"
 
-        xdata, ydata, sigma = process_curve_data(experiment_data._data, lambda datum: level2_probability(datum, '1'))
+        xdata, ydata, sigma = process_curve_data(
+            experiment_data._data, lambda datum: level2_probability(datum, "1")
+        )
         xdata *= dt_factor_in_microsec
 
         if t1_guess is None:
@@ -90,7 +92,10 @@ def _run_analysis(
             ydata,
             [amplitude_guess, t1_guess, offset_guess],
             sigma,
-            tuple([amp_bnd, t1_bnd, offset_bnd] for amp_bnd, t1_bnd, offset_bnd in zip(amplitude_bounds, t1_bounds, offset_bounds))
+            tuple(
+                [amp_bnd, t1_bnd, offset_bnd]
+                for amp_bnd, t1_bnd, offset_bnd in zip(amplitude_bounds, t1_bounds, offset_bounds)
+            ),
         )
 
         analysis_result = AnalysisResult(
@@ -100,8 +105,11 @@ def _run_analysis(
                 "unit": result_unit,
                 "label": "T1",
                 "fit": fit_result,
-                "quality": self._fit_quality(fit_result["popt"], fit_result["popt_err"], fit_result["reduced_chisq"]),
-            })
+                "quality": self._fit_quality(
+                    fit_result["popt"], fit_result["popt_err"], fit_result["reduced_chisq"]
+                ),
+            }
+        )
 
         return analysis_result, None
 

From 19bdd5af801ec7bd0daa9ee30b1a0d5ebaa555d6 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Thu, 22 Apr 2021 16:03:07 +0300
Subject: [PATCH 49/59] T1 to always return results in seconds

---
 .../characterization/t1_experiment.py         | 29 ++++++++--------
 test/test_t1.py                               | 34 +++++++++----------
 2 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index eb126cbd73..283aa66df6 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -17,6 +17,7 @@
 import numpy as np
 
 from qiskit.circuit import QuantumCircuit
+from qiskit.utils import apply_prefix
 
 from qiskit_experiments.base_experiment import BaseExperiment
 from qiskit_experiments.base_analysis import BaseAnalysis
@@ -57,24 +58,20 @@ def _run_analysis(
             The analysis result with the estimated T1
         """
 
-        circuit_unit = experiment_data._data[0]["metadata"]["unit"]
-        dt_factor_in_sec = experiment_data._data[0]["metadata"].get("dt_factor_in_sec", None)
-        if dt_factor_in_sec is None:
-            dt_factor_in_microsec = 1
-            result_unit = circuit_unit
-        else:
-            dt_factor_in_microsec = dt_factor_in_sec * 1000000
-            result_unit = "us"
+        unit = experiment_data._data[0]["metadata"]["unit"]
+        conversion_factor = experiment_data._data[0]["metadata"].get("dt_factor", None)
+        if conversion_factor is None:
+            conversion_factor = 1 if unit == "s" else apply_prefix(1, unit)
 
         xdata, ydata, sigma = process_curve_data(
             experiment_data._data, lambda datum: level2_probability(datum, "1")
         )
-        xdata *= dt_factor_in_microsec
+        xdata *= conversion_factor
 
         if t1_guess is None:
             t1_guess = np.mean(xdata)
         else:
-            t1_guess = t1_guess * dt_factor_in_microsec
+            t1_guess = t1_guess * conversion_factor
         if offset_guess is None:
             offset_guess = ydata[-1]
         if amplitude_guess is None:
@@ -102,7 +99,7 @@ def _run_analysis(
             {
                 "value": fit_result["popt"][1],
                 "stderr": fit_result["popt_err"][1],
-                "unit": result_unit,
+                "unit": "s",
                 "label": "T1",
                 "fit": fit_result,
                 "quality": self._fit_quality(
@@ -111,6 +108,10 @@ def _run_analysis(
             }
         )
 
+        if unit == "dt":
+            analysis_result["fit"]["dt"] = conversion_factor
+            analysis_result["fit"]["circuit_unit"] = unit
+
         return analysis_result, None
 
     @staticmethod
@@ -138,7 +139,7 @@ def __init__(
         self,
         qubit: int,
         delays: Union[List[float], np.array],
-        unit: Optional[str] = "us",
+        unit: Optional[str] = "s",
         experiment_type: Optional[str] = None,
     ):
         """
@@ -177,7 +178,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
 
         if self._unit == "dt":
             try:
-                dt_factor_in_sec = getattr(backend.configuration(), "dt")
+                dt_factor = getattr(backend.configuration(), "dt")
             except AttributeError as no_dt:
                 raise AttributeError("Dt parameter is missing in backend configuration") from no_dt
 
@@ -199,7 +200,7 @@ def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:
             }
 
             if self._unit == "dt":
-                circ.metadata["dt_factor_in_sec"] = dt_factor_in_sec
+                circ.metadata["dt_factor"] = dt_factor
 
             circuits.append(circ)
 
diff --git a/test/test_t1.py b/test/test_t1.py
index 7619a7a466..1a26247da3 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -30,13 +30,13 @@ class T1Backend(BaseBackend):
     A simple and primitive backend, to be run by the T1 tests
     """
 
-    def __init__(
-        self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, dt_factor_in_microsec=1e6
-    ):
+    def __init__(self, t1, initial_prob1=None, readout0to1=None, readout1to0=None, dt_factor=None):
         """
         Initialize the T1 backend
         """
 
+        dt_factor_in_ns = dt_factor * 1e9 if dt_factor is not None else None
+
         configuration = QasmBackendConfiguration(
             backend_name="t1_simulator",
             backend_version="0",
@@ -50,14 +50,14 @@ def __init__(
             memory=False,
             max_shots=int(1e6),
             coupling_map=None,
-            dt=dt_factor_in_microsec * 1000,
+            dt=dt_factor_in_ns,
         )
 
         self._t1 = t1
         self._initial_prob1 = initial_prob1
         self._readout0to1 = readout0to1
         self._readout1to0 = readout1to0
-        self._dt_factor_in_microsec = dt_factor_in_microsec
+        self._dt_factor = dt_factor
         super().__init__(configuration)
 
     # pylint: disable = arguments-differ
@@ -104,7 +104,7 @@ def run(self, qobj):
                     if op.name == "x":
                         prob1[qubit] = 1 - prob1[qubit]
                     if op.name == "delay":
-                        delay = op.params[0] * self._dt_factor_in_microsec
+                        delay = op.params[0]
                         prob1[qubit] = prob1[qubit] * np.exp(-delay / self._t1[qubit])
                     if op.name == "measure":
                         meas_res = np.random.binomial(
@@ -144,36 +144,36 @@ def test_t1_end2end(self):
         Test T1 experiment using a simulator.
         """
 
-        dt_factor_in_microsec = 0.0002
+        dt_factor = 2e-7
 
-        t1 = 25
+        t1 = 25e-6
         backend = T1Backend(
-            [t1],
+            [t1 / dt_factor],
             initial_prob1=[0.02],
             readout0to1=[0.02],
             readout1to0=[0.02],
-            dt_factor_in_microsec=dt_factor_in_microsec,
+            dt_factor=dt_factor,
         )
 
         delays = list(
             range(
-                int(1 / dt_factor_in_microsec),
-                int(40 / dt_factor_in_microsec),
-                int(3 / dt_factor_in_microsec),
+                int(1e-6 / dt_factor),
+                int(40e-6 / dt_factor),
+                int(3e-6 / dt_factor),
             )
         )
 
         # dummy numbers to avoid exception triggerring
         instruction_durations = [
-            ("measure", [0], 3 / dt_factor_in_microsec, "dt"),
-            ("x", [0], 3 / dt_factor_in_microsec, "dt"),
+            ("measure", [0], 3, "dt"),
+            ("x", [0], 3, "dt"),
         ]
 
         exp = T1Experiment(0, delays, unit="dt")
         res = exp.run(
             backend,
             amplitude_guess=1,
-            t1_guess=t1 / dt_factor_in_microsec,
+            t1_guess=t1 / dt_factor,
             offset_guess=0,
             instruction_durations=instruction_durations,
             shots=10000,
@@ -227,7 +227,7 @@ def test_t1_analysis(self):
 
         res = T1Analysis()._run_analysis(data)[0]
         self.assertEqual(res["quality"], "computer_good")
-        self.assertAlmostEqual(res["value"], 25, delta=3)
+        self.assertAlmostEqual(res["value"], 25e-9, delta=3)
 
     def test_t1_metadata(self):
         """

From b49393248359509e431884ec2d1c263239810d8b Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Tue, 27 Apr 2021 16:26:46 +0300
Subject: [PATCH 50/59] an attempt to integrate with results db

---
 qiskit_experiments/__init__.py                |   3 -
 qiskit_experiments/base_analysis.py           |   2 +-
 qiskit_experiments/base_experiment.py         |   8 +-
 .../characterization/t1_experiment.py         |  10 +-
 .../composite/composite_analysis.py           |   3 +-
 .../composite/composite_experiment_data.py    |   2 +-
 qiskit_experiments/experiment_data.py         | 141 ------------------
 test/test_t1.py                               |   2 +-
 8 files changed, 14 insertions(+), 157 deletions(-)
 delete mode 100644 qiskit_experiments/experiment_data.py

diff --git a/qiskit_experiments/__init__.py b/qiskit_experiments/__init__.py
index 42e800cb3c..7b580ac70b 100644
--- a/qiskit_experiments/__init__.py
+++ b/qiskit_experiments/__init__.py
@@ -14,9 +14,6 @@
 
 from .version import __version__
 
-# Base result classes
-from .experiment_data import ExperimentData, AnalysisResult
-
 # Experiment modules
 from . import composite
 from . import characterization
diff --git a/qiskit_experiments/base_analysis.py b/qiskit_experiments/base_analysis.py
index f6329fe203..31f06b2e4f 100644
--- a/qiskit_experiments/base_analysis.py
+++ b/qiskit_experiments/base_analysis.py
@@ -16,7 +16,7 @@
 from abc import ABC, abstractmethod
 
 from qiskit.exceptions import QiskitError
-from .experiment_data import ExperimentData, AnalysisResult
+from qiskit.providers.experiment import AnalysisResult, ExperimentData
 
 
 class BaseAnalysis(ABC):
diff --git a/qiskit_experiments/base_experiment.py b/qiskit_experiments/base_experiment.py
index fb82f4646c..6627b3eff6 100644
--- a/qiskit_experiments/base_experiment.py
+++ b/qiskit_experiments/base_experiment.py
@@ -19,7 +19,7 @@
 from qiskit import transpile, assemble
 from qiskit.exceptions import QiskitError
 
-from .experiment_data import ExperimentData
+from qiskit.providers.experiment import ExperimentDataV1
 
 
 _TRANSPILE_OPTIONS = {
@@ -57,7 +57,7 @@ class BaseExperiment(ABC):
     __analysis_class__ = None
 
     # ExperimentData class for experiment
-    __experiment_data__ = ExperimentData
+    __experiment_data__ = ExperimentDataV1
 
     # Custom default transpiler options for experiment subclasses
     __transpile_defaults__ = {"optimization_level": 0}
@@ -89,7 +89,6 @@ def __init__(self, qubits, experiment_type=None, circuit_options=None):
             self._num_qubits = len(qubits)
             self._physical_qubits = tuple(qubits)
             if self._num_qubits != len(set(self._physical_qubits)):
-                print(self._num_qubits, self._physical_qubits)
                 raise QiskitError("Duplicate qubits in physical qubits list.")
 
         # Store options and values
@@ -113,7 +112,7 @@ def run(self, backend, experiment_data=None, **kwargs):
 
         # Create new experiment data
         if experiment_data is None:
-            experiment_data = self.__experiment_data__(self)
+            experiment_data = self.__experiment_data__(backend, self._type)
 
         # Filter kwargs
         run_options = self.__run_defaults__.copy()
@@ -230,3 +229,4 @@ def transpiled_circuits(self, backend=None, **kwargs):
         circuits = transpile(circuits, backend=backend, **transpile_options)
 
         return circuits
+
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index f4625e0b18..c00c91d099 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -20,8 +20,8 @@
 
 from qiskit_experiments.base_experiment import BaseExperiment
 from qiskit_experiments.base_analysis import BaseAnalysis
-from qiskit_experiments import AnalysisResult
 from .analysis_functions import exp_fit_fun, curve_fit_wrapper
+from qiskit.providers.experiment import AnalysisResultV1
 
 
 class T1Analysis(BaseAnalysis):
@@ -38,7 +38,7 @@ def _run_analysis(
         amplitude_bounds=None,
         offset_bounds=None,
         **kwargs,
-    ) -> Tuple[AnalysisResult, None]:
+    ) -> Tuple[AnalysisResultV1, None]:
         """
         Calculate T1
 
@@ -56,8 +56,8 @@ def _run_analysis(
             The analysis result with the estimated T1
         """
 
-        circuit_unit = experiment_data._data[0]["metadata"]["unit"]
-        dt_factor_in_sec = experiment_data._data[0]["metadata"].get("dt_factor_in_sec", None)
+        circuit_unit = experiment_data.data(0)["metadata"]["unit"]
+        dt_factor_in_sec = experiment_data.data(0)["metadata"].get("dt_factor_in_sec", None)
         if dt_factor_in_sec is None:
             dt_factor_in_microsec = 1
             result_unit = circuit_unit
@@ -70,7 +70,7 @@ def _run_analysis(
         means = np.zeros(size, dtype=float)
         stddevs = np.zeros(size, dtype=float)
 
-        for i, circ in enumerate(experiment_data._data):
+        for i, circ in enumerate(experiment_data.data()):
             delays[i] = circ["metadata"]["delay"] * dt_factor_in_microsec
             count0 = circ["counts"].get("0", 0)
             count1 = circ["counts"].get("1", 0)
diff --git a/qiskit_experiments/composite/composite_analysis.py b/qiskit_experiments/composite/composite_analysis.py
index 625215e976..7b0eeddcaf 100644
--- a/qiskit_experiments/composite/composite_analysis.py
+++ b/qiskit_experiments/composite/composite_analysis.py
@@ -14,8 +14,9 @@
 """
 
 from qiskit.exceptions import QiskitError
-from qiskit_experiments.base_analysis import BaseAnalysis, AnalysisResult
+from qiskit_experiments.base_analysis import BaseAnalysis
 from .composite_experiment_data import CompositeExperimentData
+from qiskit.providers.experiment import AnalysisResult
 
 
 class CompositeAnalysis(BaseAnalysis):
diff --git a/qiskit_experiments/composite/composite_experiment_data.py b/qiskit_experiments/composite/composite_experiment_data.py
index 48dee73d8c..dfb7f4f127 100644
--- a/qiskit_experiments/composite/composite_experiment_data.py
+++ b/qiskit_experiments/composite/composite_experiment_data.py
@@ -14,7 +14,7 @@
 """
 
 from qiskit.result import marginal_counts
-from qiskit_experiments.experiment_data import ExperimentData
+from qiskit.providers.experiment import ExperimentData
 
 
 class CompositeExperimentData(ExperimentData):
diff --git a/qiskit_experiments/experiment_data.py b/qiskit_experiments/experiment_data.py
deleted file mode 100644
index b7cbda8394..0000000000
--- a/qiskit_experiments/experiment_data.py
+++ /dev/null
@@ -1,141 +0,0 @@
-# This code is part of Qiskit.
-#
-# (C) Copyright IBM 2021.
-#
-# This code is licensed under the Apache License, Version 2.0. You may
-# obtain a copy of this license in the LICENSE.txt file in the root directory
-# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
-#
-# Any modifications or derivative works of this code must retain this
-# copyright notice, and modified files need to carry a notice indicating
-# that they have been altered from the originals.
-"""
-Experiment Data class
-"""
-
-import uuid
-
-from qiskit.result import Result
-from qiskit.providers import Job, BaseJob
-from qiskit.exceptions import QiskitError
-
-
-class AnalysisResult(dict):
-    """Placeholder class"""
-
-
-class ExperimentData:
-    """ExperimentData container class"""
-
-    def __init__(self, experiment):
-        """Initialize the analysis object.
-
-        Args:
-            experiment (BaseExperiment): experiment object that
-                                         generated the data.
-        """
-        # Experiment identification metadata
-        self._id = str(uuid.uuid4())
-        self._experiment = experiment
-
-        # Experiment Data
-        self._data = []
-
-        # Analysis
-        self._analysis_results = []
-
-    def __repr__(self):
-        line = 51 * "-"
-        n_res = len(self._analysis_results)
-        ret = line
-        ret += f"\nExperiment: {self._experiment._type}"
-        ret += f"\nExperiment ID: {self.experiment_id}"
-        ret += "\nStatus: COMPLETE"
-        ret += f"\nCircuits: {len(self._data)}"
-        ret += f"\nAnalysis Results: {n_res}"
-        ret += "\n" + line
-        if n_res:
-            ret += "\nLast Analysis Result"
-            for key, value in self._analysis_results[-1].items():
-                ret += f"\n- {key}: {value}"
-        return ret
-
-    @property
-    def experiment_id(self):
-        """Return the experiment id"""
-        return self._id
-
-    def experiment(self):
-        """Return Experiment object"""
-        return self._experiment
-
-    def analysis_result(self, index):
-        """Return stored analysis results
-
-        Args:
-            index (int or slice): the result or range of results to return.
-
-        Returns:
-            AnalysisResult: the result for an integer index.
-            List[AnalysisResult]: a list of results for slice index.
-        """
-        return self._analysis_results[index]
-
-    def add_analysis_result(self, result):
-        """Add an Analysis Result
-
-        Args:
-            result (AnalysisResult): the analysis result to add.
-        """
-        self._analysis_results.append(result)
-
-    @property
-    def data(self):
-        """Return stored experiment data"""
-        return self._data
-
-    def add_data(self, data):
-        """Add data to the experiment.
-
-        Args:
-            data (Result or Job or dict or list): the circuit execution data
-                to add. This can be a Result, Job, or dict object, or a list
-                of Result, Job, or dict objects.
-
-        Raises:
-            QiskitError: if the data is not a valid format.
-        """
-        if isinstance(data, dict):
-            self._add_single_data(data)
-        elif isinstance(data, Result):
-            self._add_result_data(data)
-        elif isinstance(data, (Job, BaseJob)):
-            self._add_result_data(data.result())
-        elif isinstance(data, list):
-            for dat in data:
-                self.add_data(dat)
-        else:
-            raise QiskitError("Invalid data format.")
-
-    def _add_result_data(self, result: Result):
-        """Add data from qiskit Result object"""
-        num_data = len(result.results)
-        for i in range(num_data):
-            metadata = result.results[i].header.metadata
-            if metadata.get("experiment_type") == self._experiment._type:
-                data = result.data(i)
-                data["metadata"] = metadata
-                if "counts" in data:
-                    # Format to Counts object rather than hex dict
-                    data["counts"] = result.get_counts(i)
-                self._add_single_data(data)
-
-    def _add_single_data(self, data):
-        """Add a single data dictionary to the experiment.
-
-        Args:
-            data (dict): a data dictionary for a single circuit exection.
-        """
-        # This method is intended to be overriden by subclasses when necessary.
-        if data.get("metadata", {}).get("experiment_type") == self._experiment._type:
-            self._data.append(data)
diff --git a/test/test_t1.py b/test/test_t1.py
index 224451f527..ef449be485 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -20,7 +20,7 @@
 from qiskit.providers import BaseBackend
 from qiskit.providers.models import QasmBackendConfiguration
 from qiskit.result import Result
-from qiskit_experiments import ExperimentData
+from qiskit.providers.experiment import ExperimentDataV1
 from qiskit_experiments.composite import ParallelExperiment
 from qiskit_experiments.characterization import T1Experiment, T1Analysis
 

From a3cfa28f47c8b66fcf54102bec0f996b819f5557 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Tue, 27 Apr 2021 21:16:23 +0300
Subject: [PATCH 51/59] replaced if by elif

---
 test/test_t1.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/test_t1.py b/test/test_t1.py
index 1a26247da3..75f794db11 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -103,10 +103,10 @@ def run(self, qobj):
                     qubit = op.qubits[0]
                     if op.name == "x":
                         prob1[qubit] = 1 - prob1[qubit]
-                    if op.name == "delay":
+                    elif op.name == "delay":
                         delay = op.params[0]
                         prob1[qubit] = prob1[qubit] * np.exp(-delay / self._t1[qubit])
-                    if op.name == "measure":
+                    elif op.name == "measure":
                         meas_res = np.random.binomial(
                             1, prob1[qubit] * (1 - ro10[qubit]) + (1 - prob1[qubit]) * ro01[qubit]
                         )

From 5ec66219bfcf4e8247cfbeaf5e685ef1da643aa5 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Wed, 28 Apr 2021 22:23:11 +0300
Subject: [PATCH 52/59] Update
 qiskit_experiments/characterization/t1_experiment.py

Co-authored-by: Christopher J. Wood <cjwood@us.ibm.com>
---
 qiskit_experiments/characterization/t1_experiment.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 283aa66df6..93a6b36e85 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -148,7 +148,7 @@ def __init__(
         Args:
             qubit: the qubit whose T1 is to be estimated
             delays: delay times of the experiments
-            unit:Optional, unit of the duration. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
+            unit: Optional, unit of the delay times. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
             experiment_type: Optional, the experiment type string.
 
         Raises:

From f6380600034316b1fa466170270b18c509002557 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Wed, 28 Apr 2021 22:26:42 +0300
Subject: [PATCH 53/59] removed experiment_type from t1

---
 qiskit_experiments/characterization/t1_experiment.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 93a6b36e85..771011e736 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -140,7 +140,6 @@ def __init__(
         qubit: int,
         delays: Union[List[float], np.array],
         unit: Optional[str] = "s",
-        experiment_type: Optional[str] = None,
     ):
         """
         Initialize the T1 experiment class
@@ -149,7 +148,6 @@ def __init__(
             qubit: the qubit whose T1 is to be estimated
             delays: delay times of the experiments
             unit: Optional, unit of the delay times. Supported units: 's', 'ms', 'us', 'ns', 'ps', 'dt'.
-            experiment_type: Optional, the experiment type string.
 
         Raises:
             ValueError: if the number of delays is smaller than 3
@@ -159,7 +157,7 @@ def __init__(
 
         self._delays = delays
         self._unit = unit
-        super().__init__([qubit], experiment_type)
+        super().__init__([qubit])
 
     # pylint: disable=arguments-differ
     def circuits(self, backend: Optional["Backend"] = None) -> List[QuantumCircuit]:

From e0439186cd9c5b07c81904369ca303a76e3a8140 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Wed, 28 Apr 2021 22:35:22 +0300
Subject: [PATCH 54/59] circuit_unit should appear in the result for every unit

---
 qiskit_experiments/characterization/t1_experiment.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 771011e736..e1b23dc74d 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -108,9 +108,9 @@ def _run_analysis(
             }
         )
 
+        analysis_result["fit"]["circuit_unit"] = unit
         if unit == "dt":
             analysis_result["fit"]["dt"] = conversion_factor
-            analysis_result["fit"]["circuit_unit"] = unit
 
         return analysis_result, None
 

From 73a379b1e85d2b44507513c8da435638c84bbdb7 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Thu, 29 Apr 2021 20:31:54 +0300
Subject: [PATCH 55/59] use AnalysisResultV1

---
 qiskit_experiments/analysis/curve_fitting.py  | 16 ++++-----
 qiskit_experiments/analysis/plotting.py       | 10 +++---
 .../characterization/t1_experiment.py         | 35 +++++++++++--------
 3 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/qiskit_experiments/analysis/curve_fitting.py b/qiskit_experiments/analysis/curve_fitting.py
index b2d2e83801..bea491db7e 100644
--- a/qiskit_experiments/analysis/curve_fitting.py
+++ b/qiskit_experiments/analysis/curve_fitting.py
@@ -19,7 +19,6 @@
 import numpy as np
 import scipy.optimize as opt
 from qiskit.exceptions import QiskitError
-from qiskit_experiments.base_analysis import AnalysisResult
 from qiskit_experiments.analysis.data_processing import filter_data
 
 
@@ -31,7 +30,7 @@ def curve_fit(
     sigma: Optional[np.ndarray] = None,
     bounds: Optional[Union[Dict[str, Tuple[float, float]], Tuple[np.ndarray, np.ndarray]]] = None,
     **kwargs,
-) -> AnalysisResult:
+) -> Dict:
     r"""Perform a non-linear least squares to fit
 
     This solves the optimization problem
@@ -110,8 +109,8 @@ def fit_func(x, *params):
         kwargs["absolute_sigma"] = True
 
     # Run curve fit
-    # TODO: Add error handling so if fitting fails we can return an analysis
-    #       result containing this information
+    # TODO: Add error handling so if fitting fails we can return a
+    #       dictionary containing this information
     # pylint: disable = unbalanced-tuple-unpacking
     popt, pcov = opt.curve_fit(
         fit_func, xdata, ydata, sigma=sigma, p0=param_p0, bounds=param_bounds, **kwargs
@@ -138,7 +137,7 @@ def fit_func(x, *params):
         "xrange": xdata_range,
     }
 
-    return AnalysisResult(result)
+    return result
 
 
 def multi_curve_fit(
@@ -151,7 +150,7 @@ def multi_curve_fit(
     weights: Optional[np.ndarray] = None,
     bounds: Optional[Union[Dict[str, Tuple[float, float]], Tuple[np.ndarray, np.ndarray]]] = None,
     **kwargs,
-) -> AnalysisResult:
+) -> Dict:
     r"""Perform a linearized multi-objective non-linear least squares fit.
 
     This solves the optimization problem
@@ -230,10 +229,7 @@ def f(x, *params):
         return y
 
     # Run linearized curve_fit
-    analysis_result = curve_fit(f, xdata, ydata, p0, sigma=wsigma, bounds=bounds, **kwargs)
-
-    return analysis_result
-
+    return curve_fit(f, xdata, ydata, p0, sigma=wsigma, bounds=bounds, **kwargs)
 
 def process_curve_data(
     data: List[Dict[str, any]], data_processor: Callable, x_key: str = "xval", **filters
diff --git a/qiskit_experiments/analysis/plotting.py b/qiskit_experiments/analysis/plotting.py
index bd9312e17a..4f9cdd1be4 100644
--- a/qiskit_experiments/analysis/plotting.py
+++ b/qiskit_experiments/analysis/plotting.py
@@ -13,11 +13,9 @@
 Plotting functions for experiment analysis
 """
 import functools
-from typing import Callable, Optional
+from typing import Callable, Optional, Dict
 import numpy as np
 
-from qiskit_experiments.base_analysis import AnalysisResult
-
 try:
     from matplotlib import pyplot as plt
 
@@ -44,7 +42,7 @@ def wrapped(*args, **kwargs):
 @requires_matplotlib
 def plot_curve_fit(
     func: Callable,
-    result: AnalysisResult,
+    result: Dict,
     confidence_interval: bool = True,
     ax: Optional["AxesSubplot"] = None,
     num_fit_points: int = 100,
@@ -52,13 +50,13 @@ def plot_curve_fit(
     grid: bool = True,
     **kwargs,
 ) -> "AxesSubplot":
-    """Generate plot of a curve fit analysis result.
+    """Generate plot of a curve fitresult.
 
     Wraps ``matplotlib.pyplot.plot``.
 
     Args:
         func: the fit funcion for curve_fit.
-        result: an AnalysisResult from curve_fit.
+        result: a result dictionary from curve_fit.
         confidence_interval: if True plot the confidence interval from popt_err.
         ax: Optional, a matplotlib axes to add the plot to.
         num_fit_points: the number of points to plot for xrange.
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 589c301d47..5bc80ebaf2 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -22,6 +22,7 @@
 from qiskit_experiments.base_experiment import BaseExperiment
 from qiskit_experiments.base_analysis import BaseAnalysis
 from qiskit.providers.experiment import AnalysisResultV1
+from qiskit.providers.experiment.device_component import Qubit
 from qiskit_experiments.analysis.curve_fitting import process_curve_data, curve_fit
 from qiskit_experiments.analysis.data_processing import level2_probability
 
@@ -95,22 +96,28 @@ def _run_analysis(
             ),
         )
 
-        analysis_result = AnalysisResult(
-            {
-                "value": fit_result["popt"][1],
-                "stderr": fit_result["popt_err"][1],
-                "unit": "s",
-                "label": "T1",
-                "fit": fit_result,
-                "quality": self._fit_quality(
-                    fit_result["popt"], fit_result["popt_err"], fit_result["reduced_chisq"]
+        result_data = {
+            "value": fit_result["popt"][1],
+            "stderr": fit_result["popt_err"][1],
+            "unit": "s",
+            "label": "T1",
+            "fit": fit_result,
+            "quality": self._fit_quality(
+                fit_result["popt"], fit_result["popt_err"], fit_result["reduced_chisq"]
                 ),
             }
-        )
 
         if unit == "dt":
-            analysis_result["fit"]["dt"] = conversion_factor
-            analysis_result["fit"]["circuit_unit"] = unit
+            result_data["fit"]["dt"] = conversion_factor
+            result_data["fit"]["circuit_unit"] = unit
+
+        analysis_result = AnalysisResultV1(
+            result_data,
+            'T1',
+            [Qubit()],
+            experiment_data.id,
+            quality=result_data['quality'],
+            verified=True)
 
         return analysis_result, None
 
@@ -125,9 +132,9 @@ def _fit_quality(fit_out, fit_err, reduced_chisq):
             and (fit_err[1] is None or fit_err[1] < fit_out[1])
             and (fit_err[2] is None or fit_err[2] < 0.1)
         ):
-            return "computer_good"
+            return "good"
         else:
-            return "computer_bad"
+            return "bad"
 
 
 class T1Experiment(BaseExperiment):

From 47fc3e0232df4ed182e61d99e8ba2c2f660e60f9 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Sun, 2 May 2021 11:51:15 +0300
Subject: [PATCH 56/59] test_t1_end2end is working

---
 qiskit_experiments/characterization/t1_experiment.py | 2 +-
 qiskit_experiments/composite/parallel_experiment.py  | 2 +-
 test/test_t1.py                                      | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index ef2a900dba..56a9ce30d9 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -114,7 +114,7 @@ def _run_analysis(
         analysis_result = AnalysisResultV1(
             result_data,
             'T1',
-            [Qubit()],
+            [Qubit(experiment_data.data(0)["metadata"]["qubit"])],
             experiment_data.id,
             quality=result_data['quality'],
             verified=True)
diff --git a/qiskit_experiments/composite/parallel_experiment.py b/qiskit_experiments/composite/parallel_experiment.py
index 152709df27..71de2518be 100644
--- a/qiskit_experiments/composite/parallel_experiment.py
+++ b/qiskit_experiments/composite/parallel_experiment.py
@@ -22,7 +22,7 @@ class ParallelExperiment(CompositeExperiment):
     """Parallel Experiment class"""
 
     def __init__(self, experiments):
-        """Initialize the analysis object.
+        """Initialize the parallel experiments object.
 
         Args:
             experiments (List[BaseExperiment]): a list of experiments.
diff --git a/test/test_t1.py b/test/test_t1.py
index 4ed26ebb98..1e50ba8e35 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -20,7 +20,7 @@
 from qiskit.providers import BaseBackend
 from qiskit.providers.models import QasmBackendConfiguration
 from qiskit.result import Result
-from qiskit.providers.experiment import ExperimentDataV1
+from qiskit.providers.experiment import ExperimentDataV1, ResultQuality
 from qiskit_experiments.composite import ParallelExperiment
 from qiskit_experiments.characterization import T1Experiment, T1Analysis
 
@@ -179,8 +179,8 @@ def test_t1_end2end(self):
             shots=10000,
         ).analysis_result(0)
 
-        self.assertEqual(res["quality"], "computer_good")
-        self.assertAlmostEqual(res["value"], t1, delta=3)
+        self.assertEqual(res.quality, ResultQuality.GOOD)
+        self.assertAlmostEqual(res.data()["value"], t1, delta=3)
 
     def test_t1_parallel(self):
         """

From c5b45e19ebb2cab46e88b24d5f946ceded3c7727 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Sun, 2 May 2021 14:31:03 +0300
Subject: [PATCH 57/59] fixed test_t1_analysis

---
 .../characterization/t1_experiment.py         |  2 +-
 test/test_t1.py                               | 31 +++++++++++++------
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index 56a9ce30d9..e794947b12 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -46,7 +46,7 @@ def _run_analysis(
         Calculate T1
 
         Args:
-            experiment_data (ExperimentData): the experiment data to analyze
+            experiment_data (ExperimentDataV1): the experiment data to analyze
             t1_guess (float): Optional, an initial guess of T1
             amplitude_guess (float): Optional, an initial guess of the coefficient of the exponent
             offset_guess (float): Optional, an initial guess of the offset
diff --git a/test/test_t1.py b/test/test_t1.py
index 1e50ba8e35..6b879be616 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -208,26 +208,39 @@ def test_t1_analysis(self):
         Test T1Analysis
         """
 
-        data = ExperimentData(None)
-        numbers = [750, 1800, 2750, 3550, 4250, 4850, 5450, 5900, 6400, 6800, 7000, 7350, 7700]
+        backend_res = {
+            "backend_name": "T1 backend",
+            "backend_version": "0",
+            "qobj_id": 0,
+            "job_id": 0,
+            "success": True,
+            "results": [],
+        }
 
+        shots = 10000
+        numbers = [750, 1800, 2750, 3550, 4250, 4850, 5450, 5900, 6400, 6800, 7000, 7350, 7700]
         for i, count0 in enumerate(numbers):
-            data._data.append(
+            backend_res["results"].append(
                 {
-                    "counts": {"0": count0, "1": 10000 - count0},
-                    "metadata": {
+                    "success": True,
+                    "shots": shots,
+                    "data": {"counts": {"0": count0, "1": shots - count0}},
+                    "header": {"metadata": {
                         "xval": 3 * i + 1,
                         "experiment_type": "T1Experiment",
                         "qubit": 0,
                         "unit": "ns",
                         "dt_factor_in_sec": None,
-                    },
+                    }},
                 }
             )
 
+        data = ExperimentDataV1(None, "T1Experiment")
+        data.add_data(Result.from_dict(backend_res))
+
         res = T1Analysis()._run_analysis(data)[0]
-        self.assertEqual(res["quality"], "computer_good")
-        self.assertAlmostEqual(res["value"], 25e-9, delta=3)
+        self.assertEqual(res.quality, ResultQuality.GOOD)
+        self.assertAlmostEqual(res.data()["value"], 25e-9, delta=3)
 
     def test_t1_metadata(self):
         """
@@ -273,7 +286,7 @@ def test_t1_low_quality(self):
             )
 
         res = T1Analysis()._run_analysis(data)[0]
-        self.assertEqual(res["quality"], "computer_bad")
+        self.assertEqual(res.quality, ResultQuality.BAD)
 
 
 if __name__ == "__main__":

From 4543de7385dea4afeec2f7ac9531ced5c081b063 Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Sun, 2 May 2021 14:31:26 +0300
Subject: [PATCH 58/59] black

---
 qiskit_experiments/analysis/curve_fitting.py     |  1 +
 qiskit_experiments/base_experiment.py            |  1 -
 .../characterization/t1_experiment.py            | 11 ++++++-----
 test/test_t1.py                                  | 16 +++++++++-------
 4 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/qiskit_experiments/analysis/curve_fitting.py b/qiskit_experiments/analysis/curve_fitting.py
index bea491db7e..72b05b0094 100644
--- a/qiskit_experiments/analysis/curve_fitting.py
+++ b/qiskit_experiments/analysis/curve_fitting.py
@@ -231,6 +231,7 @@ def f(x, *params):
     # Run linearized curve_fit
     return curve_fit(f, xdata, ydata, p0, sigma=wsigma, bounds=bounds, **kwargs)
 
+
 def process_curve_data(
     data: List[Dict[str, any]], data_processor: Callable, x_key: str = "xval", **filters
 ) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
diff --git a/qiskit_experiments/base_experiment.py b/qiskit_experiments/base_experiment.py
index 6627b3eff6..62cc0a638f 100644
--- a/qiskit_experiments/base_experiment.py
+++ b/qiskit_experiments/base_experiment.py
@@ -229,4 +229,3 @@ def transpiled_circuits(self, backend=None, **kwargs):
         circuits = transpile(circuits, backend=backend, **transpile_options)
 
         return circuits
-
diff --git a/qiskit_experiments/characterization/t1_experiment.py b/qiskit_experiments/characterization/t1_experiment.py
index e794947b12..9ec13ce2db 100644
--- a/qiskit_experiments/characterization/t1_experiment.py
+++ b/qiskit_experiments/characterization/t1_experiment.py
@@ -104,8 +104,8 @@ def _run_analysis(
             "fit": fit_result,
             "quality": self._fit_quality(
                 fit_result["popt"], fit_result["popt_err"], fit_result["reduced_chisq"]
-                ),
-            }
+            ),
+        }
 
         result_data["fit"]["circuit_unit"] = unit
         if unit == "dt":
@@ -113,11 +113,12 @@ def _run_analysis(
 
         analysis_result = AnalysisResultV1(
             result_data,
-            'T1',
+            "T1",
             [Qubit(experiment_data.data(0)["metadata"]["qubit"])],
             experiment_data.id,
-            quality=result_data['quality'],
-            verified=True)
+            quality=result_data["quality"],
+            verified=True,
+        )
 
         return analysis_result, None
 
diff --git a/test/test_t1.py b/test/test_t1.py
index 6b879be616..d6b17ea789 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -225,13 +225,15 @@ def test_t1_analysis(self):
                     "success": True,
                     "shots": shots,
                     "data": {"counts": {"0": count0, "1": shots - count0}},
-                    "header": {"metadata": {
-                        "xval": 3 * i + 1,
-                        "experiment_type": "T1Experiment",
-                        "qubit": 0,
-                        "unit": "ns",
-                        "dt_factor_in_sec": None,
-                    }},
+                    "header": {
+                        "metadata": {
+                            "xval": 3 * i + 1,
+                            "experiment_type": "T1Experiment",
+                            "qubit": 0,
+                            "unit": "ns",
+                            "dt_factor_in_sec": None,
+                        }
+                    },
                 }
             )
 

From 2304ad901c5d4fde6e971344bb777eababc45e4b Mon Sep 17 00:00:00 2001
From: Yael Ben-Haim <yaelbh@il.ibm.com>
Date: Sun, 2 May 2021 14:36:42 +0300
Subject: [PATCH 59/59] fixed test_t1_low_quality

---
 test/test_t1.py | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/test/test_t1.py b/test/test_t1.py
index d6b17ea789..95aa0f5f12 100644
--- a/test/test_t1.py
+++ b/test/test_t1.py
@@ -271,22 +271,37 @@ def test_t1_low_quality(self):
         A test where the fit's quality will be low
         """
 
-        data = ExperimentData(None)
+        backend_res = {
+            "backend_name": "T1 backend",
+            "backend_version": "0",
+            "qobj_id": 0,
+            "job_id": 0,
+            "success": True,
+            "results": [],
+        }
 
+        shots = 20
         for i in range(10):
-            data._data.append(
+            backend_res["results"].append(
                 {
-                    "counts": {"0": 10, "1": 10},
-                    "metadata": {
-                        "xval": i,
-                        "experiment_type": "T1Experiment",
-                        "qubit": 0,
-                        "unit": "ns",
-                        "dt_factor_in_sec": None,
+                    "success": True,
+                    "shots": shots,
+                    "data": {"counts": {"0": 10, "1": shots - 10}},
+                    "header": {
+                        "metadata": {
+                            "xval": i,
+                            "experiment_type": "T1Experiment",
+                            "qubit": 0,
+                            "unit": "ns",
+                            "dt_factor_in_sec": None,
+                        }
                     },
                 }
             )
 
+        data = ExperimentDataV1(None, "T1Experiment")
+        data.add_data(Result.from_dict(backend_res))
+
         res = T1Analysis()._run_analysis(data)[0]
         self.assertEqual(res.quality, ResultQuality.BAD)