stimcirq

glue/cirq/stimcirq/__init__.py

@@ -1,6 +1,7 @@
 __version__ = '1.13.dev0'
 from ._cirq_to_stim import cirq_circuit_to_stim_circuit
 from ._cx_swap_gate import CXSwapGate
+from ._cz_swap_gate import CZSwapGate
 from ._det_annotation import DetAnnotation
 from ._obs_annotation import CumulativeObservableAnnotation
 from ._shift_coords_annotation import ShiftCoordsAnnotation
@@ -20,5 +21,6 @@
     "SweepPauli": SweepPauli,
     "TwoQubitAsymmetricDepolarizingChannel": TwoQubitAsymmetricDepolarizingChannel,
     "CXSwapGate": CXSwapGate,
+    "CZSwapGate": CZSwapGate,
 }
 JSON_RESOLVER = JSON_RESOLVERS_DICT.get

glue/cirq/stimcirq/_cz_swap_gate.py

@@ -0,0 +1,46 @@
+from typing import Any, Dict, List
+
+import cirq
+import stim
+
+
+@cirq.value_equality
+class CZSwapGate(cirq.Gate):
+    """Handles explaining stim's CZSWAP gates to cirq."""
+
+    def _num_qubits_(self) -> int:
+        return 2
+
+    def _circuit_diagram_info_(self, args: cirq.CircuitDiagramInfoArgs) -> List[str]:
+        return ['ZSWAP', 'ZSWAP']
+
+    def _value_equality_values_(self):
+        return ()
+
+    def _decompose_(self, qubits):
+        a, b = qubits
+        yield cirq.SWAP(a, b)
+        yield cirq.CZ(a, b)
+
+    def _stim_conversion_(self, edit_circuit: stim.Circuit, targets: List[int], **kwargs):
+        edit_circuit.append_operation('CZSWAP', targets)
+
+    def __pow__(self, power: int) -> 'CZSwapGate':
+        if power == +1:
+            return self
+        if power == -1:
+            return self
+        return NotImplemented
+
+    def __str__(self) -> str:
+        return 'CZSWAP'
+
+    def __repr__(self):
+        return f'stimcirq.CZSwapGate()'
+
+    @staticmethod
+    def _json_namespace_() -> str:
+        return ''
+
+    def _json_dict_(self) -> Dict[str, Any]:
+        return {}

glue/cirq/stimcirq/_cz_swap_test.py

@@ -0,0 +1,72 @@
+import cirq
+import stim
+import stimcirq
+
+
+def test_stim_conversion():
+    a, b, c = cirq.LineQubit.range(3)
+
+    cirq_circuit = cirq.Circuit(
+        stimcirq.CZSwapGate().on(a, b),
+        stimcirq.CZSwapGate().on(b, c),
+    )
+    stim_circuit = stim.Circuit(
+        """
+        CZSWAP 0 1
+        TICK
+        CZSWAP 1 2
+        TICK
+        """
+    )
+    assert stimcirq.cirq_circuit_to_stim_circuit(cirq_circuit) == stim_circuit
+    assert stimcirq.stim_circuit_to_cirq_circuit(stim_circuit) == cirq_circuit
+
+
+def test_diagram():
+    a, b = cirq.LineQubit.range(2)
+    cirq.testing.assert_has_diagram(
+        cirq.Circuit(
+            stimcirq.CZSwapGate()(a, b),
+            stimcirq.CZSwapGate()(a, b),
+        ),
+        """
+0: ---ZSWAP---ZSWAP---
+      |       |
+1: ---ZSWAP---ZSWAP---
+        """,
+        use_unicode_characters=False,
+    )
+
+
+def test_inverse():
+    a = stimcirq.CZSwapGate()
+    assert a**+1 == a
+    assert a**-1 == a
+
+
+def test_repr():
+    val = stimcirq.CZSwapGate()
+    assert eval(repr(val), {"stimcirq": stimcirq}) == val
+
+
+def test_equality():
+    eq = cirq.testing.EqualsTester()
+    eq.add_equality_group(stimcirq.CZSwapGate(), stimcirq.CZSwapGate())
+
+
+def test_json_serialization():
+    a, b, d = cirq.LineQubit.range(3)
+    c = cirq.Circuit(
+        stimcirq.CZSwapGate()(a, b),
+        stimcirq.CZSwapGate()(b, d),
+    )
+    json = cirq.to_json(c)
+    c2 = cirq.read_json(json_text=json, resolvers=[*cirq.DEFAULT_RESOLVERS, stimcirq.JSON_RESOLVER])
+    assert c == c2
+
+
+def test_json_backwards_compat_exact():
+    raw = stimcirq.CZSwapGate()
+    packed = '{\n  "cirq_type": "CZSwapGate"\n}'
+    assert cirq.to_json(raw) == packed
+    assert cirq.read_json(json_text=packed, resolvers=[*cirq.DEFAULT_RESOLVERS, stimcirq.JSON_RESOLVER]) == raw

glue/cirq/stimcirq/_stim_to_cirq.py

@@ -16,6 +16,7 @@
 import stim
 
 from ._cx_swap_gate import CXSwapGate
+from ._cz_swap_gate import CZSwapGate
 from ._det_annotation import DetAnnotation
 from ._measure_and_or_reset_gate import MeasureAndOrResetGate
 from ._obs_annotation import CumulativeObservableAnnotation
@@ -424,6 +425,7 @@ def handler(
                     measure=False, reset=True, basis='X', invert_measure=False, key=''
                 )
             ),
+            "CZSWAP": gate(CZSwapGate()),
             "CXSWAP": gate(CXSwapGate(inverted=False)),
             "SWAPCX": gate(CXSwapGate(inverted=True)),
             "RY": gate(