Remove some 0.15 items from cirq.sim (quantumlib#5137)

This covers most of the deprecations for `cirq.sim` in 0.15. The two remaining ones have some challenges:

* Removing `target_tensor` etc from the initializers and replacing with `initial_state`: The repr still emits `target_tensor` so it wouldn't round-trip.
* Removing `log_of_measurement_results`: Same thing. Plus we forgot to deprecate it in a couple places.

Also this closes quantumlib#3898, as the pattern we used to deprecate `copy` without parameters works well.

Author: daxfohl

cirq/protocols/act_on_protocol_test.py

@@ -31,9 +31,6 @@ def __init__(self, fallback_result: Any = NotImplemented, measurements=None):
     def _perform_measurement(self, qubits):
         return self.measurements  # coverage: ignore
 
-    def copy(self, deep_copy_buffers: bool = True):
-        return DummyActOnArgs(self.fallback_result, self.measurements.copy())  # coverage: ignore
-
     def _act_on_fallback_(
         self,
         action: Any,
@@ -42,9 +39,6 @@ def _act_on_fallback_(
     ):
         return self.fallback_result
 
-    def sample(self, qubits, repetitions=1, seed=None):
-        pass
-
 
 op = cirq.X(cirq.LineQubit(0))
 

cirq/sim/act_on_args.py

@@ -13,8 +13,6 @@
 # limitations under the License.
 """Objects and methods for acting efficiently on a state tensor."""
 import copy
-import inspect
-import warnings
 from typing import (
     Any,
     cast,
@@ -31,8 +29,8 @@
 
 import numpy as np
 
-from cirq import ops, protocols, value
-from cirq._compat import deprecated, deprecated_parameter
+from cirq import protocols, value
+from cirq._compat import deprecated
 from cirq.protocols.decompose_protocol import _try_decompose_into_operations_and_qubits
 from cirq.sim.operation_target import OperationTarget
 
@@ -45,18 +43,11 @@
 class ActOnArgs(OperationTarget[TSelf]):
     """State and context for an operation acting on a state tensor."""
 
-    @deprecated_parameter(
-        deadline='v0.15',
-        fix='Use cirq.dephase_measurements to transform the circuit before simulating.',
-        parameter_desc='ignore_measurement_results',
-        match=lambda args, kwargs: 'ignore_measurement_results' in kwargs or len(args) > 4,
-    )
     def __init__(
         self,
         prng: Optional[np.random.RandomState] = None,
         qubits: Optional[Sequence['cirq.Qid']] = None,
         log_of_measurement_results: Optional[Dict[str, List[int]]] = None,
-        ignore_measurement_results: bool = False,
         classical_data: Optional['cirq.ClassicalDataStore'] = None,
         state: Optional['cirq.QuantumStateRepresentation'] = None,
     ):
@@ -70,10 +61,6 @@ def __init__(
                 ordering of the computational basis states.
             log_of_measurement_results: A mutable object that measurements are
                 being recorded into.
-            ignore_measurement_results: If True, then the simulation
-                will treat measurement as dephasing instead of collapsing
-                process, and not log the result. This is only applicable to
-                simulators that can represent mixed states.
             classical_data: The shared classical data container for this
                 simulation.
             state: The underlying quantum state of the simulation.
@@ -90,7 +77,6 @@ def __init__(
                 for k, v in (log_of_measurement_results or {}).items()
             }
         )
-        self._ignore_measurement_results = ignore_measurement_results
         self._state = state
 
     @property
@@ -101,32 +87,14 @@ def prng(self) -> np.random.RandomState:
     def qubit_map(self) -> Mapping['cirq.Qid', int]:
         return self._qubit_map
 
-    @prng.setter  # type: ignore
-    @deprecated(
-        deadline="v0.15",
-        fix="The mutators of this class are deprecated, instantiate a new object instead.",
-    )
-    def prng(self, prng):
-        self._prng = prng
-
-    @qubit_map.setter  # type: ignore
-    @deprecated(
-        deadline="v0.15",
-        fix="The mutators of this class are deprecated, instantiate a new object instead.",
-    )
-    def qubit_map(self, qubit_map):
-        self._qubit_map = qubit_map
-
     def _set_qubits(self, qubits: Sequence['cirq.Qid']):
         self._qubits = tuple(qubits)
         self._qubit_map = {q: i for i, q in enumerate(self.qubits)}
 
     def measure(self, qubits: Sequence['cirq.Qid'], key: str, invert_mask: Sequence[bool]):
         """Measures the qubits and records to `log_of_measurement_results`.
 
-        Any bitmasks will be applied to the measurement record. If
-        `self._ignore_measurement_results` is set, it dephases instead of
-        measuring, and no measurement result will be logged.
+        Any bitmasks will be applied to the measurement record.
 
         Args:
             qubits: The qubits to measure.
@@ -138,9 +106,6 @@ def measure(self, qubits: Sequence['cirq.Qid'], key: str, invert_mask: Sequence[
         Raises:
             ValueError: If a measurement key has already been logged to a key.
         """
-        if self.ignore_measurement_results:
-            self._act_on_fallback_(ops.phase_damp(1), qubits)
-            return
         bits = self._perform_measurement(qubits)
         corrected = [bit ^ (bit < 2 and mask) for bit, mask in zip(bits, invert_mask)]
         self._classical_data.record_measurement(
@@ -181,18 +146,8 @@ def copy(self: TSelf, deep_copy_buffers: bool = True) -> TSelf:
         args._classical_data = self._classical_data.copy()
         if self._state is not None:
             args._state = self._state.copy(deep_copy_buffers=deep_copy_buffers)
-            return args
-        if 'deep_copy_buffers' in inspect.signature(self._on_copy).parameters:
-            self._on_copy(args, deep_copy_buffers)
         else:
-            warnings.warn(
-                (
-                    'A new parameter deep_copy_buffers has been added to ActOnArgs._on_copy(). '
-                    'The classes that inherit from ActOnArgs should support it before Cirq 0.15.'
-                ),
-                DeprecationWarning,
-            )
-            self._on_copy(args)
+            self._on_copy(args, deep_copy_buffers)
         return args
 
     def _on_copy(self: TSelf, args: TSelf, deep_copy_buffers: bool = True):
@@ -304,9 +259,10 @@ def _on_transpose_to_qubit_order(self: TSelf, qubits: Sequence['cirq.Qid'], targ
     def classical_data(self) -> 'cirq.ClassicalDataStoreReader':
         return self._classical_data
 
-    @property
+    @property  # type: ignore
+    @deprecated(deadline='v0.16', fix='Remove this call, it always returns False.')
     def ignore_measurement_results(self) -> bool:
-        return self._ignore_measurement_results
+        return False
 
     @property
     def qubits(self) -> Tuple['cirq.Qid', ...]:

cirq/sim/act_on_args_container.py

@@ -12,8 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import inspect
-import warnings
 from collections import abc
 from typing import (
     Any,
@@ -31,7 +29,7 @@
 import numpy as np
 
 from cirq import ops, protocols, value
-from cirq._compat import deprecated, deprecated_parameter
+from cirq._compat import deprecated_parameter
 from cirq.sim.operation_target import OperationTarget
 from cirq.sim.simulator import (
     TActOnArgs,
@@ -51,7 +49,7 @@ class ActOnArgsContainer(
     @deprecated_parameter(
         deadline='v0.15',
         fix='Use classical_data.',
-        parameter_desc='log_of_measurement_results and positional arguments',
+        parameter_desc='log_of_measurement_results',
         match=lambda args, kwargs: 'log_of_measurement_results' in kwargs or len(args) > 4,
     )
     def __init__(
@@ -94,22 +92,6 @@ def args(self) -> Mapping[Optional['cirq.Qid'], TActOnArgs]:
     def split_untangled_states(self) -> bool:
         return self._split_untangled_states
 
-    @args.setter  # type: ignore
-    @deprecated(
-        deadline="v0.15",
-        fix="The mutators of this class are deprecated, instantiate a new object instead.",
-    )
-    def args(self, args):
-        self._args = args
-
-    @split_untangled_states.setter  # type: ignore
-    @deprecated(
-        deadline="v0.15",
-        fix="The mutators of this class are deprecated, instantiate a new object instead.",
-    )
-    def split_untangled_states(self, split_untangled_states):
-        self._split_untangled_states = split_untangled_states
-
     def create_merged_state(self) -> TActOnArgs:
         if not self.split_untangled_states:
             return self.args[None]
@@ -169,11 +151,8 @@ def _act_on_fallback_(
         protocols.act_on(action, op_args, act_on_qubits, allow_decompose=allow_decompose)
 
         # Decouple any measurements or resets
-        if self.split_untangled_states and (
-            isinstance(gate_opt, ops.ResetChannel)
-            or (
-                isinstance(gate_opt, ops.MeasurementGate) and not op_args.ignore_measurement_results
-            )
+        if self.split_untangled_states and isinstance(
+            gate_opt, (ops.ResetChannel, ops.MeasurementGate)
         ):
             for q in qubits:
                 if op_args.allows_factoring:
@@ -189,17 +168,7 @@ def copy(self, deep_copy_buffers: bool = True) -> 'cirq.ActOnArgsContainer[TActO
         classical_data = self._classical_data.copy()
         copies = {}
         for act_on_args in set(self.args.values()):
-            if 'deep_copy_buffers' in inspect.signature(act_on_args.copy).parameters:
-                copies[act_on_args] = act_on_args.copy(deep_copy_buffers)
-            else:
-                warnings.warn(
-                    (
-                        'A new parameter deep_copy_buffers has been added to ActOnArgs.copy(). The '
-                        'classes that inherit from ActOnArgs should support it before Cirq 0.15.'
-                    ),
-                    DeprecationWarning,
-                )
-                copies[act_on_args] = act_on_args.copy()
+            copies[act_on_args] = act_on_args.copy(deep_copy_buffers)
         for copy in copies.values():
             copy._classical_data = classical_data
         args = {q: copies[a] for q, a in self.args.items()}

cirq/sim/act_on_args_container_test.py

@@ -26,13 +26,6 @@ def __init__(self, qubits, classical_data):
     def _perform_measurement(self, qubits: Sequence[cirq.Qid]) -> List[int]:
         return [0] * len(qubits)
 
-    def copy(self) -> 'EmptyActOnArgs':  # type: ignore
-        """The deep_copy_buffers parameter is omitted to trigger a deprecation warning test."""
-        return EmptyActOnArgs(
-            qubits=self.qubits,
-            classical_data=self.classical_data.copy(),
-        )
-
     def _act_on_fallback_(
         self,
         action: Any,
@@ -216,12 +209,6 @@ def test_copy_succeeds():
     assert copied.qubits == (q0, q1)
 
 
-def test_copy_deprecation_warning():
-    args = create_container(qs2, False)
-    with cirq.testing.assert_deprecated('deep_copy_buffers', deadline='0.15'):
-        args.copy(False)
-
-
 def test_merge_succeeds():
     args = create_container(qs2, False)
     merged = args.create_merged_state()
@@ -273,11 +260,3 @@ def test_field_getters():
     args = create_container(qs2)
     assert args.args.keys() == set(qs2) | {None}
     assert args.split_untangled_states
-
-
-def test_field_setters_deprecated():
-    args = create_container(qs2)
-    with cirq.testing.assert_deprecated(deadline='v0.15'):
-        args.args = {}
-    with cirq.testing.assert_deprecated(deadline='v0.15'):
-        args.split_untangled_states = False

cirq/sim/act_on_args_test.py

@@ -24,9 +24,6 @@ class DummyArgs(cirq.ActOnArgs):
     def __init__(self):
         super().__init__(qubits=cirq.LineQubit.range(2))
 
-    def sample(self, qubits, repetitions=1, seed=None):
-        pass
-
     def _perform_measurement(self, qubits):
         return [5, 3]
 
@@ -38,9 +35,6 @@ def _act_on_fallback_(
     ) -> bool:
         return True
 
-    def _on_copy(self, args):
-        return super()._on_copy(args)
-
 
 def test_measurements():
     args = DummyArgs()
@@ -95,21 +89,9 @@ def test_transpose_qubits():
         args.transpose_to_qubit_order((q0, q1, q1))
 
 
-def test_on_copy_has_no_param():
-    args = DummyArgs()
-    with cirq.testing.assert_deprecated('deep_copy_buffers', deadline='0.15'):
-        args.copy(False)
-
-
 def test_field_getters():
     args = DummyArgs()
     assert args.prng is np.random
     assert args.qubit_map == {q: i for i, q in enumerate(cirq.LineQubit.range(2))}
-
-
-def test_field_setters_deprecated():
-    args = DummyArgs()
-    with cirq.testing.assert_deprecated(deadline='v0.15'):
-        args.prng = 0
-    with cirq.testing.assert_deprecated(deadline='v0.15'):
-        args.qubit_map = {}
+    with cirq.testing.assert_deprecated('always returns False', deadline='v0.16'):
+        assert not args.ignore_measurement_results

cirq/sim/act_on_density_matrix_args.py

@@ -242,30 +242,24 @@ class ActOnDensityMatrixArgs(ActOnArgs):
     @_compat.deprecated_parameter(
         deadline='v0.15',
         fix='Use classical_data.',
-        parameter_desc='log_of_measurement_results and positional arguments',
+        parameter_desc='log_of_measurement_results',
         match=lambda args, kwargs: 'log_of_measurement_results' in kwargs or len(args) > 5,
     )
     @_compat.deprecated_parameter(
         deadline='v0.15',
-        fix='Use cirq.dephase_measurements to transform the circuit before simulating.',
-        parameter_desc='ignore_measurement_results',
-        match=lambda args, kwargs: 'ignore_measurement_results' in kwargs or len(args) > 7,
-    )
-    @_compat.deprecated_parameter(
-        deadline='v0.15',
-        fix='Use initial_state instead and specify all the arguments with keywords.',
-        parameter_desc='target_tensor and positional arguments',
-        match=lambda args, kwargs: 'target_tensor' in kwargs or len(args) != 1,
+        fix='Use initial_state instead.',
+        parameter_desc='target_tensor',
+        match=lambda args, kwargs: 'target_tensor' in kwargs,
     )
     def __init__(
         self,
+        *,
         target_tensor: Optional[np.ndarray] = None,
         available_buffer: Optional[List[np.ndarray]] = None,
         qid_shape: Optional[Tuple[int, ...]] = None,
         prng: Optional[np.random.RandomState] = None,
         log_of_measurement_results: Optional[Dict[str, List[int]]] = None,
         qubits: Optional[Sequence['cirq.Qid']] = None,
-        ignore_measurement_results: bool = False,
         initial_state: Union[np.ndarray, 'cirq.STATE_VECTOR_LIKE'] = 0,
         dtype: Type[np.number] = np.complex64,
         classical_data: Optional['cirq.ClassicalDataStore'] = None,
@@ -288,10 +282,6 @@ def __init__(
                 effects.
             log_of_measurement_results: A mutable object that measurements are
                 being recorded into.
-            ignore_measurement_results: If True, then the simulation
-                will treat measurement as dephasing instead of collapsing
-                process. This is only applicable to simulators that can
-                model dephasing.
             initial_state: The initial state for the simulation in the
                 computational basis.
             dtype: The `numpy.dtype` of the inferred state vector. One of
@@ -310,23 +300,13 @@ def __init__(
             dtype=dtype,
             buffer=available_buffer,
         )
-        if ignore_measurement_results:
-            super().__init__(
-                state=state,
-                prng=prng,
-                qubits=qubits,
-                log_of_measurement_results=log_of_measurement_results,
-                ignore_measurement_results=ignore_measurement_results,
-                classical_data=classical_data,
-            )
-        else:
-            super().__init__(
-                state=state,
-                prng=prng,
-                qubits=qubits,
-                log_of_measurement_results=log_of_measurement_results,
-                classical_data=classical_data,
-            )
+        super().__init__(
+            state=state,
+            prng=prng,
+            qubits=qubits,
+            log_of_measurement_results=log_of_measurement_results,
+            classical_data=classical_data,
+        )
         self._state: _BufferedDensityMatrix = state
 
     def _act_on_fallback_(