Add support for CSXGate().inverse() (#379)

Fixes #309
Qiskit · Aug 22, 2023 · d933abc · d933abc
1 parent 9cc17ed
commit d933abc
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diff --git a/circuit_knitting/cutting/qpd/qpd.py b/circuit_knitting/cutting/qpd/qpd.py
@@ -25,6 +25,7 @@
 from qiskit.circuit import (
     QuantumCircuit,
     Gate,
+    ControlledGate,
     Instruction,
     ClassicalRegister,
     CircuitInstruction,
@@ -41,6 +42,7 @@
     SXGate,
     SXdgGate,
     TGate,
+    TdgGate,
     RXGate,
     RYGate,
     RZGate,
@@ -953,6 +955,14 @@ def _(gate: CSXGate):
     return retval
 
 
+@_register_qpdbasis_from_instruction("csxdg")
+def _(gate: ControlledGate):
+    retval = qpdbasis_from_instruction(CRXGate(-np.pi / 2))
+    for operations in unique_by_id(m[0] for m in retval.maps):
+        operations.insert(0, TdgGate())
+    return retval
+
+
 @_register_qpdbasis_from_instruction("cx", "cy", "cz", "ch")
 def _(gate: CXGate | CYGate | CZGate | CHGate):
     # Constructing a virtual two-qubit gate by sampling single-qubit operations - Mitarai et al

diff --git a/test/cutting/qpd/test_qpd.py b/test/cutting/qpd/test_qpd.py
@@ -264,6 +264,7 @@ def test_decompose_qpd_instructions(self):
         (CSGate(), 1 + np.sqrt(2)),
         (CSdgGate(), 1 + np.sqrt(2)),
         (CSXGate(), 1 + np.sqrt(2)),
+        (CSXGate().inverse(), 1 + np.sqrt(2)),
         (SwapGate(), 7),
         (iSwapGate(), 7),
         (DCXGate(), 7),
@@ -442,6 +443,7 @@ def test_explicitly_supported_gates(self):
                 "cz",
                 "ch",
                 "csx",
+                "csxdg",
                 "cs",
                 "csdg",
                 "cp",

diff --git a/test/cutting/test_cutting_roundtrip.py b/test/cutting/test_cutting_roundtrip.py
@@ -69,6 +69,7 @@ def append_random_unitary(circuit: QuantumCircuit, qubits):
         [CHGate()],
         [ECRGate()],
         [CSXGate()],
+        [CSXGate().inverse()],
         [CSGate()],
         [CSdgGate()],
         [RYYGate(0.0)],