Make explicitly_supported_gates private and remove its release note

It's not clear that this function remains useful now that we support essentially all 2-qubit gates. If we find a use for it in the future, we can re-introduce it (or something like it) as a public interface.
Qiskit · Jul 24, 2023 · 8e95c4a · 8e95c4a
1 parent f43d474
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diff --git a/circuit_knitting/cutting/__init__.py b/circuit_knitting/cutting/__init__.py
@@ -57,7 +57,6 @@
     qpd.generate_qpd_weights
     qpd.generate_qpd_samples
     qpd.decompose_qpd_instructions
-    qpd.explicitly_supported_gates
     qpd.qpdbasis_from_gate
 
 CutQC

diff --git a/circuit_knitting/cutting/qpd/__init__.py b/circuit_knitting/cutting/qpd/__init__.py
@@ -18,7 +18,6 @@
     decompose_qpd_instructions,
     WeightType,
     qpdbasis_from_gate,
-    explicitly_supported_gates,
 )
 from .instructions import (
     BaseQPDGate,
@@ -32,7 +31,6 @@
     "generate_qpd_weights",
     "generate_qpd_samples",
     "decompose_qpd_instructions",
-    "explicitly_supported_gates",
     "QPDBasis",
     "BaseQPDGate",
     "TwoQubitQPDGate",

diff --git a/circuit_knitting/cutting/qpd/qpd.py b/circuit_knitting/cutting/qpd/qpd.py
@@ -559,11 +559,10 @@ def qpdbasis_from_gate(gate: Gate) -> QPDBasis:
     """
     Generate a :class:`.QPDBasis` object, given a supported operation.
 
-    The operations with explicit support can be obtained by calling
-    :func:`explicitly_supported_gates`.
-
-    Additionally, all two-qubit gates which implement the :meth:`.Gate.to_matrix` method are
-    supported via a KAK decomposition (:class:`.TwoQubitWeylDecomposition`).
+    All two-qubit gates which implement the :meth:`.Gate.to_matrix` method are
+    supported.  This should include the vast majority of gates with no unbound
+    parameters, but there are some special cases (see, e.g., `qiskit issue #10396
+    <https://github.com/Qiskit/qiskit-terra/issues/10396>`__).
 
     Returns:
         The newly-instantiated :class:`QPDBasis` object
@@ -602,7 +601,7 @@ def qpdbasis_from_gate(gate: Gate) -> QPDBasis:
     raise ValueError(f"Gate not supported: {gate.name}") from None
 
 
-def explicitly_supported_gates() -> set[str]:
+def _explicitly_supported_gates() -> set[str]:
     """
     Return a set of instruction names with explicit support for automatic decomposition.
 

diff --git a/releasenotes/notes/supported-gates-d2156f58bc07fc7a.yaml b/releasenotes/notes/supported-gates-d2156f58bc07fc7a.yaml
diff --git a/test/cutting/qpd/test_qpd.py b/test/cutting/qpd/test_qpd.py
@@ -47,6 +47,7 @@
     _generate_exact_weights_and_conditional_probabilities,
     _nonlocal_qpd_basis_from_u,
     _u_from_thetavec,
+    _explicitly_supported_gates,
 )
 
 
@@ -426,7 +427,7 @@ def from_theta(theta):
             assert weights[map_ids][1] == WeightType.SAMPLED
 
     def test_explicitly_supported_gates(self):
-        gates = explicitly_supported_gates()
+        gates = _explicitly_supported_gates()
         self.assertEqual(
             {
                 "rxx",