Merge pull request #192 from BoxiLi/cleaning

- Remove some unnecessary branching that was used for the compatibility of `qutip-v5`. They are no longer needed in the new alpha version.
- Update the pulse paper examples to be compatible with `qutip-v5`.
- Update the documentation to be compatible with `qutip-v5`.

doc/pulse-paper/customize.py

@@ -15,15 +15,13 @@
 import numpy as np
 from qutip import (
     fidelity, sigmax, sigmay, sigmaz, basis, qeye, tensor, Qobj, fock_dm)
-from qutip_qip.circuit import QubitCircuit, Gate
+from qutip_qip.circuit import QubitCircuit
+from qutip_qip.operations import Gate
 from qutip_qip.device import ModelProcessor, Model
 from qutip_qip.compiler import GateCompiler, Instruction
 import qutip
 from packaging.version import parse as parse_version
-if parse_version(qutip.__version__) < parse_version('5.dev'):
-    from qutip import Options as SolverOptions
-else:
-    from qutip import SolverOptions
+from qutip import Options
 from qutip_qip.noise import Noise
 
 
@@ -219,7 +217,7 @@ def single_crosstalk_simulation(num_gates):
     init_state = tensor(
         [Qobj([[init_fid, 0], [0, 0.025]]), Qobj([[init_fid, 0], [0, 0.025]])]
     )
-    options = SolverOptions(nsteps=10000)  # increase the maximal allowed steps
+    options = Options(nsteps=10000)  # increase the maximal allowed steps
     e_ops = [tensor([qeye(2), fock_dm(2)])]  # observable
 
     # compute results of the run using a solver of choice with custom options

doc/pulse-paper/dj_algorithm.py

@@ -18,6 +18,8 @@
     OptPulseProcessor, LinearSpinChain, SCQubits, SpinChainModel)
 from qutip_qip.circuit import QubitCircuit
 from qutip import sigmaz, sigmax, identity, tensor, basis
+from qutip_qip.compat import to_scalar
+
 
 # Deutsch-Josza algorithm
 dj_circuit = QubitCircuit(num_qubits)
@@ -79,7 +81,6 @@
     ax[i].fill_between([full_tlist[point2], full_tlist[point3]], [vmin ,vmin],  [vmax, vmax], color="lightgray", alpha=0.5)
     ax[i].vlines([full_tlist[point2], full_tlist[point3]], vmin, vmax, "gray", "--", linewidth=0.8, alpha=0.5)
 
-fig.tight_layout()
 fig.savefig("optimal_control_pulse.pdf")
 fig.show()
 
@@ -124,7 +125,6 @@
 
 full_tlist = scqubits_processor.get_full_tlist()
 
-fig3.tight_layout()
 fig3.savefig("transmon_pulse.pdf")
 fig3.show()
 
@@ -146,7 +146,7 @@
 for state in result1.states:
     tmp = state.ptrace([0,1])
     tmp = basis([2,2], [0,0]).dag() * tmp * basis([2,2], [0,0])
-    expect.append(np.real(tmp[0, 0]))
+    expect.append(np.real(to_scalar(tmp)))
 
 fig5, ax5 = plt.subplots(figsize=(LINEWIDTH, LINEWIDTH*0.7), dpi=200)
 ax5.plot(t_record, expect, color="slategrey")

doc/source/qip-basics.rst

@@ -197,7 +197,7 @@ gate function returning a :class:`qutip.Qobj` and save it in the attribute ``use
            # controlled rotation X
            mat = np.zeros((4, 4), dtype=np.complex)
            mat[0, 0] = mat[1, 1] = 1.
-           mat[2:4, 2:4] = rx(arg_value)
+           mat[2:4, 2:4] = rx(arg_value).full()
            return Qobj(mat, dims=[[2, 2], [2, 2]])
 
 

src/qutip_qip/circuit/circuit.py

@@ -346,9 +346,7 @@ def add_circuit(self, qc, start=0, overwrite_user_gates=False):
             self.user_gates[user_gate] = qc.user_gates[user_gate]
 
         for circuit_op in qc.gates:
-
             if isinstance(circuit_op, Gate):
-
                 if circuit_op.targets is not None:
                     tar = [target + start for target in circuit_op.targets]
                 else:
@@ -958,9 +956,7 @@ def latex_code(self):
                 col = []
                 _swap_processing = False
                 for n in range(self.N + self.num_cbits):
-
                     if gate.targets and n in gate.targets:
-
                         if len(gate.targets) > 1:
                             if gate.name == "SWAP":
                                 if _swap_processing:
@@ -1041,7 +1037,6 @@ def latex_code(self):
                 measurement = op
                 col = []
                 for n in range(self.N + self.num_cbits):
-
                     if n in measurement.targets:
                         col.append(r" \meter")
                     elif (n - self.N) == measurement.classical_store:

src/qutip_qip/circuit/circuitsimulator.py

@@ -183,7 +183,6 @@ def _gate_sequence_product(U_list, ind_list):
     overall_inds = []
 
     for i, (U, inds) in enumerate(zip(U_list, ind_list)):
-
         # when the tensor_list covers the full dimension of the circuit, we
         # expand the tensor_list to a unitary and call _gate_sequence_product
         # recursively on the rest of the U_list.

src/qutip_qip/compat.py

@@ -0,0 +1,15 @@
+"""
+For the compatibility between qutip-v5 and v4.
+"""
+from itertools import chain
+from functools import reduce
+from packaging.version import parse as parse_version
+import numpy as np
+import qutip
+
+
+def to_scalar(qobj_or_scalar):
+    if isinstance(qobj_or_scalar, qutip.Qobj):
+        if qobj_or_scalar.dims == [[1], [1]]:
+            return qobj_or_scalar[0, 0]
+    return qobj_or_scalar

src/qutip_qip/device/processor.py

@@ -723,7 +723,7 @@ def find_pulse(self, pulse_name):
         else:
             try:
                 return self.pulses[pulse_dict[pulse_name]]
-            except (KeyError):
+            except KeyError:
                 raise KeyError(
                     "Pulse name {} undefined. "
                     "Please define it in the attribute "
@@ -1209,10 +1209,12 @@ def run_state(
             options = kwargs.get("options", qutip.Options())
             if options.get("max_step", 0.0) == 0.0:
                 options["max_step"] = total_circuit_time / 25
+            options["progress_bar"] = False
         else:
             options = kwargs.get("options", qutip.Options())
             if options.max_step == 0.0:
                 options.max_step = total_circuit_time / 10
+            options.progress_bar = False
         kwargs["options"] = options
         # choose solver:
         if solver == "mesolve":

src/qutip_qip/operations/gates.py

@@ -1104,7 +1104,6 @@ def qubit_clifford_group(N=None, target=0):
         partial(reduce, mul),
         product(_powers(E, 3), _powers(X, 2), _powers(S, 4)),
     ):
-
         # partial(reduce, mul) returns a function that takes products
         # of its argument, by analogy to sum. Note that by analogy,
         # sum can be written as partial(reduce, add).

src/qutip_qip/qasm.py

@@ -134,7 +134,6 @@ def _tokenize(token_cmds):
     processed_commands = []
 
     for line in token_cmds:
-
         # carry out some pre-processing for convenience
         for c in "[]()":
             line = line.replace(c, " " + c + " ")
@@ -241,7 +240,6 @@ def _process_includes(self):
         expanded_commands = []
 
         for curr_index, command in enumerate(self.commands):
-
             if command[0] != "include":
                 continue
 
@@ -384,7 +382,6 @@ def _custom_gate(self, qc_temp, gate_call):
             regs_map[reg] = regs[i]
         # process all the constituent gates with supplied arguments, registers
         for call in gate.gates_inside:
-
             # create function call for the constituent gate
             name, com_args, com_regs = call
 
@@ -455,7 +452,6 @@ def _regs_processor(self, regs, reg_type):
             regs = new_regs
 
         if reg_type == "measure":
-
             # processes register tokens of the form q[i] -> c[i]
             groups = re.match(r"(.*)\[(.*)\]->(.*)\[(.*)\]", "".join(regs))
             if groups:

src/qutip_qip/qir.py

@@ -112,6 +112,7 @@ def circuit_to_qir(circuit, format, module_name="qutip_circuit"):
     A QIR representation of `circuit`, encoded using the format specified by
     `format`.
     """
+
     # Define as an inner function to make it easier to call from conditional
     # branches.
     def append_operation(

src/qutip_qip/qiskit/backend.py

@@ -29,7 +29,6 @@ class QiskitSimulatorBase(BackendV1):
     """
 
     def __init__(self, configuration=None, **fields):
-
         if configuration is None:
             configuration_dict = self._DEFAULT_CONFIGURATION
         else:
@@ -160,7 +159,6 @@ class QiskitCircuitSimulator(QiskitSimulatorBase):
     }
 
     def __init__(self, configuration=None, **fields):
-
         super().__init__(configuration=configuration, **fields)
 
     def _parse_results(
@@ -325,7 +323,6 @@ class QiskitPulseSimulator(QiskitSimulatorBase):
     }
 
     def __init__(self, processor: Processor, configuration=None, **fields):
-
         self.processor = processor
         super().__init__(configuration=configuration, **fields)
 

src/qutip_qip/transpiler/chain.py

@@ -99,7 +99,6 @@ def to_chain_structure(qc, setup="linear"):
                 temp = QubitCircuit(N - end + start)
                 i = 0
                 while i < (N - end + start):
-
                     if (
                         N + start - end - i - i == 1
                         and (N - end + start + 1) % 2 == 0
@@ -215,7 +214,6 @@ def to_chain_structure(qc, setup="linear"):
                 temp = QubitCircuit(N - end + start)
                 i = 0
                 while i < (N - end + start):
-
                     if (
                         N + start - end - i - i == 1
                         and (N - end + start + 1) % 2 == 0

src/qutip_qip/vqa.py

@@ -7,6 +7,7 @@
 from scipy.optimize import minimize
 from scipy.linalg import expm_frechet
 from .operations import gate_sequence_product
+from .compat import to_scalar
 
 
 class VQA:
@@ -429,10 +430,8 @@ def cost_derivative(self, U, dU):
         dCost = (init.dag() * dU.dag()) * obs * (U * init) + (
             init.dag() * U.dag()
         ) * obs * (dU * init)
-        if isinstance(dCost, Qobj):  # qutip version < 5
-            return np.real(dCost.full().item())
-        else:  # qutip version >= 5
-            return np.real(dCost)
+        dCost = to_scalar(dCost)
+        return np.real(dCost)
 
     def compute_jac(self, angles, indices_to_compute=None):
         """

tests/pytest.ini

@@ -7,3 +7,4 @@ markers =
 filterwarnings =
     ignore:matplotlib not found:UserWarning
     ignore:the imp module is deprecated in favour of importlib:DeprecationWarning
+    ignore:Dedicated options class are no longer needed, options should be passed as dict to solvers.:FutureWarning

tests/test_noise.py

@@ -15,10 +15,6 @@
 
 import qutip
 from packaging.version import parse as parse_version
-if parse_version(qutip.__version__) >= parse_version('5.dev'):
-    is_qutip5 = True
-else:
-    is_qutip5 = False
 
 
 class TestNoise:

tests/test_processor.py

@@ -7,10 +7,6 @@
 import pytest
 
 import qutip
-if parse_version(qutip.__version__) < parse_version('5.dev'):
-    from qutip import Options as SolverOptions
-else:
-    from qutip import SolverOptions
 from qutip_qip.device import Processor, LinearSpinChain
 from qutip import (
     basis, sigmaz, sigmax, sigmay, identity, destroy, tensor,
@@ -21,10 +17,7 @@
 from qutip_qip.qubits import qubit_states
 from qutip_qip.pulse import Pulse
 from qutip_qip.circuit import QubitCircuit
-if parse_version(qutip.__version__) < parse_version('5.dev'):
-    from qutip import Options as SolverOptions
-else:
-    from qutip import SolverOptions
+from qutip import Options
 
 
 class TestCircuitProcessor:
@@ -96,7 +89,7 @@ def test_id_evolution(self):
         tlist = [0., 1., 2.]
         proc.add_pulse(Pulse(identity(2), 0, tlist, False))
         result = proc.run_state(
-            init_state, options=SolverOptions(store_final_state=True))
+            init_state, options=Options(store_final_state=True))
         global_phase = init_state[0, 0]/result.final_state[0, 0]
         assert_allclose(
             global_phase*result.final_state.full(), init_state.full())
@@ -407,7 +400,7 @@ def test_max_step_size(self):
         # No max_step
         final_state = processor.run_state(
             init_state,
-            options=SolverOptions(max_step=10000)  # too large max_step
+            options=Options(max_step=10000)  # too large max_step
         ).states[-1]
         expected_state = tensor([basis(2, 0), basis(2, 1)])
         assert pytest.approx(fidelity(final_state, expected_state), 0.001) == 0