Deprecate cirq_google.ConvertToXmonGates and replace with cirq.CZTargetGateset + cirq.optimize_for_target_gateset (#5096)

Part of #5028

Author: tanujkhattar

cirq-google/cirq_google/devices/xmon_device.py

@@ -16,7 +16,6 @@
 
 import cirq
 from cirq import _compat
-from cirq_google.optimizers import convert_to_xmon_gates
 
 if TYPE_CHECKING:
     import cirq
@@ -52,6 +51,7 @@ def __init__(
                 cirq.XPowGate,
                 cirq.YPowGate,
                 cirq.PhasedXPowGate,
+                cirq.PhasedXZGate,
                 cirq.MeasurementGate,
                 cirq.ZPowGate,
             ),
@@ -72,10 +72,17 @@ def qubit_set(self) -> FrozenSet[cirq.GridQubit]:
 
     @_compat.deprecated(
         deadline='v0.15',
-        fix='XmonDevice.decompose_operation is deperecated. Please use ConvertToXmonGates().',
+        fix='XmonDevice.decompose_operation is deprecated. '
+        'Please use cirq.optimize_for_target_gateset() and cirq.CZTargetGateset.',
     )
     def decompose_operation(self, operation: cirq.Operation) -> cirq.OP_TREE:
-        return convert_to_xmon_gates.ConvertToXmonGates().convert(operation)
+        if operation.gate is not None and self.is_supported_gate(operation.gate):
+            return operation
+        return [
+            cirq.optimize_for_target_gateset(
+                cirq.Circuit(operation), gateset=cirq.CZTargetGateset(allow_partial_czs=True)
+            ).all_operations()
+        ]
 
     def neighbors_of(self, qubit: cirq.GridQubit):
         """Returns the qubits that the given qubit can interact with."""
@@ -109,6 +116,7 @@ def is_supported_gate(cls, gate: cirq.Gate):
                 cirq.XPowGate,
                 cirq.YPowGate,
                 cirq.PhasedXPowGate,
+                cirq.PhasedXZGate,
                 cirq.MeasurementGate,
                 cirq.ZPowGate,
             ),

cirq-google/cirq_google/devices/xmon_device_test.py

@@ -52,6 +52,7 @@ def test_device_metadata():
         cirq.XPowGate,
         cirq.YPowGate,
         cirq.PhasedXPowGate,
+        cirq.PhasedXZGate,
         cirq.MeasurementGate,
         cirq.ZPowGate,
     )

cirq-google/cirq_google/optimizers/convert_to_xmon_gates.py

@@ -16,6 +16,10 @@
 import cirq
 
 
+@cirq._compat.deprecated_class(
+    deadline='v1.0',
+    fix='Use cirq.optimize_for_target_gateset and cirq.CZTargetGateset instead.',
+)
 class ConvertToXmonGates(cirq.PointOptimizer):
     """Attempts to convert strange gates into XmonGates.
 

cirq-google/cirq_google/optimizers/convert_to_xmon_gates_test.py

@@ -40,8 +40,10 @@ class NonNativeGate(cirq.SingleQubitGate):
 def test_avoids_infinite_cycle_when_matrix_available():
     q = cirq.GridQubit(0, 0)
     c = cirq.Circuit(OtherX().on(q), OtherOtherX().on(q))
-    cirq_google.ConvertToXmonGates().optimize_circuit(c)
+    with cirq.testing.assert_deprecated("Use cirq.optimize_for_target_gateset", deadline='v1.0'):
+        cirq_google.ConvertToXmonGates().optimize_circuit(c)
     cirq.testing.assert_has_diagram(c, '(0, 0): ───PhX(1)───PhX(1)───')
+
     cirq.protocols.decompose(c)
 
 
@@ -52,7 +54,10 @@ def test_avoids_infinite_cycle_when_matrix_available():
 def test_bad_operation():
     c = cirq.Circuit(NonNativeGate().on(q[0]))
     with pytest.raises(TypeError):
-        cirq_google.ConvertToXmonGates().optimize_circuit(c)
+        with cirq.testing.assert_deprecated(
+            "Use cirq.optimize_for_target_gateset", deadline='v1.0'
+        ):
+            cirq_google.ConvertToXmonGates().optimize_circuit(c)
 
 
 @pytest.mark.parametrize(
@@ -68,4 +73,5 @@ def test_bad_operation():
 )
 def test_supported_operation(op, is_valid):
     c = cirq.Circuit(op)
-    assert (cirq_google.ConvertToXmonGates().optimization_at(c, 0, op) is not None) == is_valid
+    with cirq.testing.assert_deprecated("Use cirq.optimize_for_target_gateset", deadline='v1.0'):
+        assert (cirq_google.ConvertToXmonGates().optimization_at(c, 0, op) is not None) == is_valid

cirq-google/cirq_google/optimizers/optimize_for_sycamore.py

@@ -13,49 +13,18 @@
 # limitations under the License.
 """A combination of several optimizations targeting XmonDevice."""
 from functools import lru_cache
-from typing import Callable, cast, List, Optional, TYPE_CHECKING
+from typing import Callable, cast, Optional, TYPE_CHECKING
 
 import numpy as np
 
 import cirq
 from cirq_google import ops as cg_ops
-from cirq_google.optimizers import (
-    convert_to_xmon_gates,
-)
 from cirq_google.transformers.target_gatesets import sycamore_gateset
 
 if TYPE_CHECKING:
     import cirq_google
 
 
-def _get_xmon_optimizers(
-    tolerance: float, tabulation: Optional[cirq.TwoQubitGateTabulation]
-) -> List[Callable[[cirq.Circuit], None]]:
-    if tabulation is not None:
-        # coverage: ignore
-        raise ValueError("Gate tabulation not supported for xmon")
-
-    return [
-        convert_to_xmon_gates.ConvertToXmonGates().optimize_circuit,
-    ]
-
-
-def _get_xmon_optimizers_part_cz(
-    tolerance: float, tabulation: Optional[cirq.TwoQubitGateTabulation]
-) -> List[Callable[[cirq.Circuit], None]]:
-    if tabulation is not None:
-        # coverage: ignore
-        raise ValueError("Gate tabulation not supported for xmon")
-    return [
-        convert_to_xmon_gates.ConvertToXmonGates().optimize_circuit,
-    ]
-
-
-_OPTIMIZER_TYPES = {
-    'xmon': _get_xmon_optimizers,
-    'xmon_partial_cz': _get_xmon_optimizers_part_cz,
-}
-
 _TARGET_GATESETS = {
     'sqrt_iswap': lambda atol, _: cirq.SqrtIswapTargetGateset(atol=atol),
     'sycamore': lambda atol, tabulation: sycamore_gateset.SycamoreTargetGateset(
@@ -122,10 +91,10 @@ def optimized_for_sycamore(
         ValueError: If the `optimizer_type` is not a supported type.
     """
     copy = circuit.copy()
-    if optimizer_type not in _OPTIMIZER_TYPES and optimizer_type not in _TARGET_GATESETS:
+    if optimizer_type not in _TARGET_GATESETS:
         raise ValueError(
             f'{optimizer_type} is not an allowed type.  Allowed '
-            f'types are: {_OPTIMIZER_TYPES.keys()}'
+            f'types are: {_TARGET_GATESETS.keys()}'
         )
 
     tabulation: Optional[cirq.TwoQubitGateTabulation] = None
@@ -137,10 +106,6 @@ def optimized_for_sycamore(
             circuit,
             gateset=_TARGET_GATESETS[optimizer_type](tolerance, tabulation),
         )
-    if optimizer_type in _OPTIMIZER_TYPES:
-        opts = _OPTIMIZER_TYPES[optimizer_type](tolerance=tolerance, tabulation=tabulation)
-        for optimizer in opts:
-            optimizer(copy)
     copy = cirq.merge_single_qubit_gates_to_phxz(copy, atol=tolerance)
     copy = cirq.eject_phased_paulis(copy, atol=tolerance)
     copy = cirq.eject_z(copy, atol=tolerance)