depr: remove legacy opmath (#283)

src/braket/pennylane_plugin/ahs_device.py

@@ -38,11 +38,10 @@
 from typing import Optional, Union
 
 import numpy as np
-import pennylane as qml
 from pennylane._version import __version__
 from pennylane.devices import QubitDevice
 from pennylane.measurements import MeasurementProcess, SampleMeasurement
-from pennylane.ops import CompositeOp, Hamiltonian
+from pennylane.ops import CompositeOp
 from pennylane.pulse import ParametrizedEvolution
 from pennylane.pulse.hardware_hamiltonian import HardwareHamiltonian, HardwarePulse
 
@@ -312,9 +311,6 @@ def _validate_measurement_basis(self, observable):
         if isinstance(observable, CompositeOp):
             for op in observable.operands:
                 self._validate_measurement_basis(op)
-        elif isinstance(observable, (Hamiltonian, qml.Hamiltonian)):
-            for op in observable.ops:
-                self._validate_measurement_basis(op)
 
         elif not observable.has_diagonalizing_gates:
             raise RuntimeError(

src/braket/pennylane_plugin/braket_device.py

@@ -60,7 +60,7 @@
     Variance,
 )
 from pennylane.operation import Operation
-from pennylane.ops import Hamiltonian, Sum
+from pennylane.ops import Sum
 from pennylane.tape import QuantumTape
 
 from braket.aws import (
@@ -287,7 +287,7 @@ def _apply_gradient_result_type(self, circuit, braket_circuit):
                 f"Braket can only compute gradients for circuits with a single expectation"
                 f" observable, not a {pl_measurements.return_type} observable."
             )
-        if isinstance(pl_observable, (Hamiltonian, Sum)):
+        if isinstance(pl_observable, Sum):
             targets = [self.map_wires(op.wires) for op in pl_observable.terms()[1]]
         else:
             targets = self.map_wires(pl_observable.wires).tolist()

src/braket/pennylane_plugin/translation.py

@@ -534,7 +534,7 @@ def supported_observables(device: Device, shots: int) -> frozenset[str]:
         *[_BRAKET_TO_PENNYLANE_OBSERVABLES[braket_obs] for braket_obs in braket_observables],
     )
     supported |= {"Prod", "SProd"}
-    return supported if shots else supported | {"Sum", "Hamiltonian", "LinearCombination"}
+    return supported if shots else supported | {"Sum", "LinearCombination"}
 
 
 def get_adjoint_gradient_result_type(
@@ -568,7 +568,7 @@ def translate_result_type(  # noqa: C901
 
     Returns:
         Union[ResultType, tuple[ResultType]]: The Braket result type corresponding to
-        the given observable; if the observable type has multiple terms, for example a Hamiltonian,
+        the given observable; if the observable type has multiple terms, for example a Sum,
         then this will return a result type for each term.
     """
     return_type = measurement.return_type
@@ -595,7 +595,7 @@ def translate_result_type(  # noqa: C901
     if isinstance(observable, qml.ops.LinearCombination):
         if return_type is ObservableReturnTypes.Expectation:
             return tuple(Expectation(_translate_observable(op)) for op in observable.terms()[1])
-        raise NotImplementedError(f"Return type {return_type} unsupported for Hamiltonian")
+        raise NotImplementedError(f"Return type {return_type} unsupported for LinearCombination")
 
     braket_observable = _translate_observable(observable)
     if return_type is ObservableReturnTypes.Expectation:
@@ -609,7 +609,7 @@ def translate_result_type(  # noqa: C901
 
 
 def _flatten_observable(observable):
-    if isinstance(observable, (qml.ops.Hamiltonian, qml.ops.CompositeOp, qml.ops.SProd)):
+    if isinstance(observable, (qml.ops.CompositeOp, qml.ops.SProd)):
         simplified = qml.ops.LinearCombination(*observable.terms()).simplify()
         coeffs, _ = simplified.terms()
         if len(coeffs) > 1 or coeffs[0] != 1:
@@ -669,11 +669,6 @@ def _(obs: qml.Projector):
     return observables.Hermitian(obs.matrix(), targets=wires)
 
 
-@_translate_observable.register
-def _(t: qml.operation.Tensor):
-    return reduce(lambda x, y: x @ y, [_translate_observable(factor) for factor in t.obs])
-
-
 @_translate_observable.register
 def _(t: qml.ops.Prod):
     return reduce(lambda x, y: x @ y, [_translate_observable(factor) for factor in t.operands])

test/unit_tests/test_ahs_device.py

@@ -467,25 +467,6 @@ def test_check_validity_valid_circuit(self, H, params):
 
         dev.check_validity(ops, obs)
 
-    @pytest.mark.parametrize("H, params", HAMILTONIANS_AND_PARAMS)
-    def test_check_validity_valid_circuit_no_op_math(self, H, params):
-        """Tests that check_validity() doesn't raise any errors when the operations and
-        observables are valid."""
-        qml.operation.disable_new_opmath()
-        ops = [ParametrizedEvolution(H, params, [0, 1.5])]
-        obs = [
-            qml.PauliZ(0),
-            qml.expval(qml.PauliZ(0)),
-            qml.var(qml.Identity(0)),
-            qml.sample(qml.PauliZ(0)),
-            qml.prod(qml.PauliZ(0), qml.Identity(1)),
-            qml.Hamiltonian([2, 3], [qml.PauliZ(0), qml.PauliZ(1)]),
-            qml.counts(),
-        ]
-        dev = qml.device("braket.local.ahs", wires=3)
-
-        dev.check_validity(ops, obs)
-
     @pytest.mark.parametrize("H, params", HAMILTONIANS_AND_PARAMS)
     def test_check_validity_raises_error_for_state_based_measurement(self, H, params):
         """Tests that requesting a measurement other than a sample-based

test/unit_tests/test_braket_device.py

@@ -569,7 +569,6 @@ def test_execute_with_gradient_no_op_math(
     result_types,
     expected_pl_result,
 ):
-    qml.operation.disable_new_opmath()
 
     task = Mock()
     type(task).id = PropertyMock(return_value="task_arn")
@@ -830,8 +829,8 @@ def test_pl_to_braket_circuit_hamiltonian():
 
 
 def test_pl_to_braket_circuit_hamiltonian_tensor_product_terms():
-    """Tests that a PennyLane circuit is correctly converted into a Braket circuit"""
-    """when the Hamiltonian has multiple tensor product ops"""
+    """Tests that a PennyLane circuit is correctly converted into a Braket circuit
+    when the Hamiltonian has multiple tensor product ops"""
     dev = _aws_device(wires=2, foo="bar")
 
     with QuantumTape() as tape:

test/unit_tests/test_translation.py

@@ -749,7 +749,7 @@ def test_translate_result_type_hamiltonian_unsupported_return(return_type):
     with Hamiltonian observable and non-Expectation return type"""
     obs = qml.Hamiltonian((2, 3), (qml.PauliX(wires=0), qml.PauliY(wires=1)))
     tape = qml.tape.QuantumTape(measurements=[_braket_to_pl_result_types[return_type](obs)])
-    with pytest.raises(NotImplementedError, match="unsupported for Hamiltonian"):
+    with pytest.raises(NotImplementedError, match="unsupported for LinearCombination"):
         translate_result_type(tape.measurements[0], [0], frozenset())