Rename qml.Interferometer to qml.InterferometerUnitary

doc/introduction/operations.rst

@@ -262,7 +262,7 @@ CV Gates
     ~pennylane.CrossKerr
     ~pennylane.CubicPhase
     ~pennylane.Displacement
-    ~pennylane.Interferometer
+    ~pennylane.InterferometerUnitary
     ~pennylane.Kerr
     ~pennylane.QuadraticPhase
     ~pennylane.Rotation

doc/releases/changelog-dev.md

@@ -431,6 +431,10 @@
   `requires_grad=False` was explicitly set.
   [(#1638)](https://github.com/PennyLaneAI/pennylane/pull/1638)
 
+- The operation `qml.Interferometer` has been renamed `qml.InterferometerUnitary` in order to 
+  distinguish it from the template `qml.templates.Interferometer`.
+  [(#1714)](https://github.com/PennyLaneAI/pennylane/pull/1714)
+
 <h3>Deprecations</h3>
 
 * The `qml.fourier.spectrum` function has been renamed to `qml.fourier.circuit_spectrum`,
@@ -479,5 +483,6 @@
 
 This release contains contributions from (in alphabetical order):
 
-Utkarsh Azad, Olivia Di Matteo, Andrew Gardhouse, Josh Izaac, Christina Lee, Romain Moyard,
-Carrie-Anne Rubidge, Maria Schuld, Ingrid Strandberg, Antal Száva, Cody Wang, David Wierichs.
+Utkarsh Azad, Akash Narayanan B, Olivia Di Matteo, Andrew Gardhouse, Josh Izaac, Christina Lee,
+Romain Moyard, Carrie-Anne Rubidge, Maria Schuld, Ingrid Strandberg, Antal Száva, Cody Wang,
+David Wierichs.

pennylane/circuit_drawer/representation_resolver.py

@@ -420,7 +420,7 @@ def operator_representation(self, op, wire):
             "FockDensityMatrix",
             "FockStateVector",
             "QubitStateVector",
-            "Interferometer",
+            "InterferometerUnitary",
         }:
             representation = name + RepresentationResolver._format_matrix_arguments(
                 op.data, "M", self.matrix_cache

pennylane/devices/default_gaussian.py

@@ -305,8 +305,8 @@ def controlled_phase(s):
     return S
 
 
-def interferometer(U):
-    """Interferometer
+def interferometer_unitary(U):
+    """InterferometerUnitary
 
     Args:
         U (array): unitary matrix
@@ -668,7 +668,7 @@ class DefaultGaussian(Device):
         "SqueezedState": squeezed_state,
         "ThermalState": thermal_state,
         "GaussianState": gaussian_state,
-        "Interferometer": interferometer,
+        "InterferometerUnitary": interferometer_unitary,
     }
 
     _observable_map = {

pennylane/ops/cv.py

@@ -35,8 +35,6 @@
 # As the qubit based ``decomposition``, ``_matrix``, ``diagonalizing_gates``
 # abstract methods are not defined in the CV case, disabling the related check
 # pylint: disable=abstract-method
-import warnings
-
 import math
 import numpy as np
 from scipy.linalg import block_diag
@@ -553,8 +551,8 @@ def adjoint(self, do_queue=False):
         return CubicPhase(-self.parameters[0], wires=self.wires, do_queue=do_queue)
 
 
-class Interferometer(CVOperation):
-    r"""pennylane.Interferometer(U, wires)
+class InterferometerUnitary(CVOperation):
+    r"""pennylane.InterferometerUnitary(U, wires)
     A linear interferometer transforming the bosonic operators according to
     the unitary matrix :math:`U`.
 
@@ -588,15 +586,6 @@ class Interferometer(CVOperation):
         wires (Sequence[int] or int): the wires the operation acts on
     """
 
-    def __init__(self, *args, **kwargs):
-        warnings.warn(
-            "'Interferometer' is deprecated and will be renamed 'InterferometerUnitary'",
-            UserWarning,
-            stacklevel=2,
-        )
-
-        super().__init__(*args, **kwargs)
-
     num_params = 1
     num_wires = AnyWires
     par_domain = "A"
@@ -618,7 +607,9 @@ def _heisenberg_rep(p):
 
     def adjoint(self, do_queue=False):
         U = self.parameters[0]
-        return Interferometer(qml_math.T(qml_math.conj(U)), wires=self.wires, do_queue=do_queue)
+        return InterferometerUnitary(
+            qml_math.T(qml_math.conj(U)), wires=self.wires, do_queue=do_queue
+        )
 
 
 # =============================================================================
@@ -1170,7 +1161,7 @@ class FockStateProjector(CVObservable):
     "Squeezing",
     "TwoModeSqueezing",
     "CubicPhase",
-    "Interferometer",
+    "InterferometerUnitary",
     "CatState",
     "CoherentState",
     "FockDensityMatrix",
@@ -1183,15 +1174,7 @@ class FockStateProjector(CVObservable):
 }
 
 
-obs = {
-    "QuadOperator",
-    "NumberOperator",
-    "TensorN",
-    "P",
-    "X",
-    "PolyXP",
-    "FockStateProjector",
-}
+obs = {"QuadOperator", "NumberOperator", "TensorN", "P", "X", "PolyXP", "FockStateProjector"}
 
 
 __all__ = list(ops | obs)

tests/circuit_drawer/test_representation_resolver.py

@@ -139,8 +139,8 @@ def test_single_parameter_representation(self, unicode_representation_resolver,
             (qml.CrossKerr(3.14, wires=[1, 2]), 1, "CrossKerr(3.14)"),
             (qml.CrossKerr(3.14, wires=[1, 2]), 2, "CrossKerr(3.14)"),
             (qml.CubicPhase(3.14, wires=[1]), 1, "V(3.14)"),
-            (qml.Interferometer(np.eye(4), wires=[1, 3]), 1, "Interferometer(M0)"),
-            (qml.Interferometer(np.eye(4), wires=[1, 3]), 3, "Interferometer(M0)"),
+            (qml.InterferometerUnitary(np.eye(4), wires=[1, 3]), 1, "InterferometerUnitary(M0)"),
+            (qml.InterferometerUnitary(np.eye(4), wires=[1, 3]), 3, "InterferometerUnitary(M0)"),
             (qml.CatState(3.14, 2.14, 1, wires=[1]), 1, "CatState(3.14, 2.14, 1)"),
             (qml.CoherentState(3.14, 2.14, wires=[1]), 1, "CoherentState(3.14, 2.14)"),
             (
@@ -280,8 +280,8 @@ def test_operator_representation_unicode(
             (qml.CrossKerr(3.14, wires=[1, 2]), 1, "CrossKerr(3.14)"),
             (qml.CrossKerr(3.14, wires=[1, 2]), 2, "CrossKerr(3.14)"),
             (qml.CubicPhase(3.14, wires=[1]), 1, "V(3.14)"),
-            (qml.Interferometer(np.eye(4), wires=[1, 3]), 1, "Interferometer(M0)"),
-            (qml.Interferometer(np.eye(4), wires=[1, 3]), 3, "Interferometer(M0)"),
+            (qml.InterferometerUnitary(np.eye(4), wires=[1, 3]), 1, "InterferometerUnitary(M0)"),
+            (qml.InterferometerUnitary(np.eye(4), wires=[1, 3]), 3, "InterferometerUnitary(M0)"),
             (qml.CatState(3.14, 2.14, 1, wires=[1]), 1, "CatState(3.14, 2.14, 1)"),
             (qml.CoherentState(3.14, 2.14, wires=[1]), 1, "CoherentState(3.14, 2.14)"),
             (

tests/devices/test_default_gaussian.py

@@ -412,7 +412,7 @@ def test_apply(self, gaussian_dev, tol):
                     p = [cov, mu]
                     w = list(range(2))
                     expected_out = [cov, mu]
-                elif gate_name == "Interferometer":
+                elif gate_name == "InterferometerUnitary":
                     w = list(range(2))
                     p = [U]
                     S = fn(*p)
@@ -464,12 +464,12 @@ def test_apply_errors(self, gaussian_dev):
 
         with pytest.raises(ValueError, match="Incorrect number of subsystems"):
             p = U
-            gaussian_dev.apply("Interferometer", wires=Wires([0]), par=[p])
+            gaussian_dev.apply("InterferometerUnitary", wires=Wires([0]), par=[p])
 
         with pytest.raises(qml.wires.WireError, match="Did not find some of the wires"):
             p = U2
             # dev = DefaultGaussian(wires=4, shots=1000, hbar=hbar)
-            gaussian_dev.apply("Interferometer", wires=Wires([0, 1, 2]), par=[p])
+            gaussian_dev.apply("InterferometerUnitary", wires=Wires([0, 1, 2]), par=[p])
 
     def test_expectation(self, tol):
         """Test that expectation values are calculated correctly"""
@@ -819,7 +819,7 @@ def reference(*x):
 
         if g == "GaussianState":
             p = [np.diag([0.5234] * 4), np.array([0.432, 0.123, 0.342, 0.123])]
-        elif g == "Interferometer":
+        elif g == "InterferometerUnitary":
             p = [U]
         else:
             p = [0.432423, -0.12312, 0.324, 0.763][: op.num_params]

tests/gradients/test_parameter_shift_cv.py

@@ -661,7 +661,7 @@ def test_gradients_gaussian_circuit(self, op, obs, mocker, tol):
             assert np.allclose(grad_A, grad_F, atol=tol, rtol=0)
 
     @pytest.mark.parametrize("t", [0, 1])
-    def test_interferometer(self, t, tol):
+    def test_interferometer_unitary(self, t, tol):
         """An integration test for CV gates that support analytic differentiation
         if succeeding the gate to be differentiated, but cannot be differentiated
         themselves (for example, they may be Gaussian but accept no parameters,
@@ -670,7 +670,7 @@ def test_interferometer(self, t, tol):
         This ensures that, assuming their _heisenberg_rep is defined, the quantum
         gradient analytic method can still be used, and returns the correct result.
 
-        Currently, the only such operation is qml.Interferometer. In the future,
+        Currently, the only such operation is qml.InterferometerUnitary. In the future,
         we may consider adding a qml.GaussianTransfom operator.
         """
 
@@ -690,7 +690,7 @@ def test_interferometer(self, t, tol):
             # @qml.qnode(dev)
             # def circuit(r, phi):
             #     qml.Displacement(r, phi, wires=0)
-            #     qml.Interferometer(U, wires=[0, 1])
+            #     qml.InterferometerUnitary(U, wires=[0, 1])
             #     return qml.expval(qml.X(0))
             #
             # r = 0.543
@@ -711,7 +711,7 @@ def test_interferometer(self, t, tol):
 
         with qml.tape.JacobianTape() as tape:
             qml.Displacement(0.543, 0, wires=0)
-            qml.Interferometer(U, wires=[0, 1])
+            qml.InterferometerUnitary(U, wires=[0, 1])
             qml.expval(qml.X(0))
 
         tape.trainable_params = {t}

tests/ops/test_cv_ops.py

@@ -55,7 +55,12 @@ def test_rotation_heisenberg(self, phi):
             (cv.Displacement(2.004, 8.673, wires=0), 3),  # phi > 2pi
             (cv.Beamsplitter(0.456, -0.789, wires=[0, 2]), 5),
             (cv.TwoModeSqueezing(2.532, 1.778, wires=[1, 2]), 5),
-            (cv.Interferometer(np.array([[1, 1], [1, -1]]) * -1.0j / np.sqrt(2.0), wires=1), 5),
+            (
+                cv.InterferometerUnitary(
+                    np.array([[1, 1], [1, -1]]) * -1.0j / np.sqrt(2.0), wires=1
+                ),
+                5,
+            ),
             (cv.ControlledAddition(2.551, wires=[0, 2]), 5),
             (cv.ControlledPhase(2.189, wires=[3, 1]), 5),
         ],
@@ -70,14 +75,6 @@ def test_adjoint_cv_ops(self, op, size, tol):
         np_testing.assert_allclose(res2, np.eye(size), atol=tol)
         assert op.wires == op_d.wires
 
-    def test_Interferometer_deprecation_warning(self):
-        """Tests whether a ``UserWarning`` is raised when ``Interferometer`` gate is used."""
-        with pytest.warns(
-            UserWarning,
-            match="'Interferometer' is deprecated and will be renamed 'InterferometerUnitary'",
-        ):
-            cv.Interferometer(np.array([[1, 1], [1, -1]]) * -1.0j / np.sqrt(2.0), wires=1)
-
     @pytest.mark.parametrize(
         "op",
         [
@@ -129,34 +126,10 @@ def test_beamsplitter_heisenberg(self, phi, theta):
         true_matrix = np.array(
             [
                 [1, 0, 0, 0, 0],
-                [
-                    0,
-                    np.cos(theta),
-                    0,
-                    -np.cos(phi) * np.sin(theta),
-                    -np.sin(phi) * np.sin(theta),
-                ],
-                [
-                    0,
-                    0,
-                    np.cos(theta),
-                    np.sin(phi) * np.sin(theta),
-                    -np.cos(phi) * np.sin(theta),
-                ],
-                [
-                    0,
-                    np.cos(phi) * np.sin(theta),
-                    -np.sin(phi) * np.sin(theta),
-                    np.cos(theta),
-                    0,
-                ],
-                [
-                    0,
-                    np.sin(phi) * np.sin(theta),
-                    np.cos(phi) * np.sin(theta),
-                    0,
-                    np.cos(theta),
-                ],
+                [0, np.cos(theta), 0, -np.cos(phi) * np.sin(theta), -np.sin(phi) * np.sin(theta)],
+                [0, 0, np.cos(theta), np.sin(phi) * np.sin(theta), -np.cos(phi) * np.sin(theta)],
+                [0, np.cos(phi) * np.sin(theta), -np.sin(phi) * np.sin(theta), np.cos(theta), 0],
+                [0, np.sin(phi) * np.sin(theta), np.cos(phi) * np.sin(theta), 0, np.cos(theta)],
             ]
         )
         assert np.allclose(matrix, true_matrix)
@@ -190,13 +163,7 @@ def test_controlled_addition_heisenberg(self, s):
         """ops: Tests the Heisenberg representation of ControlledAddition gate."""
         matrix = cv.ControlledAddition._heisenberg_rep([s])
         true_matrix = np.array(
-            [
-                [1, 0, 0, 0, 0],
-                [0, 1, 0, 0, 0],
-                [0, 0, 1, 0, -s],
-                [0, s, 0, 1, 0],
-                [0, 0, 0, 0, 1],
-            ]
+            [[1, 0, 0, 0, 0], [0, 1, 0, 0, 0], [0, 0, 1, 0, -s], [0, s, 0, 1, 0], [0, 0, 0, 0, 1]]
         )
         assert np.allclose(matrix, true_matrix)
 
@@ -205,13 +172,7 @@ def test_controlled_phase_heisenberg(self, s):
         """Tests the Heisenberg representation of the ControlledPhase gate."""
         matrix = cv.ControlledPhase._heisenberg_rep([s])
         true_matrix = np.array(
-            [
-                [1, 0, 0, 0, 0],
-                [0, 1, 0, 0, 0],
-                [0, 0, 1, s, 0],
-                [0, 0, 0, 1, 0],
-                [0, s, 0, 0, 1],
-            ]
+            [[1, 0, 0, 0, 0], [0, 1, 0, 0, 0], [0, 0, 1, s, 0], [0, 0, 0, 1, 0], [0, s, 0, 0, 1]]
         )
         assert np.allclose(matrix, true_matrix)
 

tests/tape/test_cv_param_shift.py

@@ -631,7 +631,7 @@ def test_gradients_gaussian_circuit(self, op, obs, mocker, tol):
             assert np.allclose(grad_A, grad_F, atol=tol, rtol=0)
 
     @pytest.mark.parametrize("t", [0, 1])
-    def test_interferometer(self, t, tol):
+    def test_interferometer_unitary(self, t, tol):
         """An integration test for CV gates that support analytic differentiation
         if succeeding the gate to be differentiated, but cannot be differentiated
         themselves (for example, they may be Gaussian but accept no parameters,
@@ -640,7 +640,7 @@ def test_interferometer(self, t, tol):
         This ensures that, assuming their _heisenberg_rep is defined, the quantum
         gradient analytic method can still be used, and returns the correct result.
 
-        Currently, the only such operation is qml.Interferometer. In the future,
+        Currently, the only such operation is qml.InterferometerUnitary. In the future,
         we may consider adding a qml.GaussianTransfom operator.
         """
 
@@ -660,7 +660,7 @@ def test_interferometer(self, t, tol):
             # @qml.qnode(dev)
             # def circuit(r, phi):
             #     qml.Displacement(r, phi, wires=0)
-            #     qml.Interferometer(U, wires=[0, 1])
+            #     qml.InterferometerUnitary(U, wires=[0, 1])
             #     return qml.expval(qml.X(0))
 
             #
@@ -681,7 +681,7 @@ def test_interferometer(self, t, tol):
 
         with CVParamShiftTape() as tape:
             qml.Displacement(0.543, 0, wires=0)
-            qml.Interferometer(U, wires=[0, 1])
+            qml.InterferometerUnitary(U, wires=[0, 1])
             qml.expval(qml.X(0))
 
         tape._update_gradient_info()

tests/test_operation.py

@@ -57,7 +57,7 @@ def test_heisenberg(self, test_class, tol):
 
         # fixed parameter values
         if test_class.par_domain == "A":
-            if test_class.__name__ == "Interferometer":
+            if test_class.__name__ == "InterferometerUnitary":
                 ww = list(range(2))
                 par = [
                     np.array(