change: Clean up GateConnectivityCriterion instantiation logic.

src/braket/emulators/emulator_passes/criteria/gate_connectivity_criterion.py

@@ -17,47 +17,43 @@ def __init__(
         directed=True,
     ):
         super().__init__()
-        if isinstance(gate_connectivity_graph, DiGraph):
-            self._gate_connectivity_graph = gate_connectivity_graph
-            if not directed:
-                for u, v in self._gate_connectivity_graph.edges:
-                    back_edge = (v, u)
-                    if back_edge not in self._gate_connectivity_graph.edges:
-                        supported_gates = self._gate_connectivity_graph[u][v]["supported_gates"]
-                        self._gate_connectivity_graph.add_edge(
-                            *back_edge, supported_gates=supported_gates
-                        )
-                    else:
-                        # check that the supported gate sets are identical
-                        if (
-                            self._gate_connectivity_graph[u][v]["supported_gates"]
-                            != self._gate_connectivity_graph[v][u]["supported_gates"]
-                        ):
-                            raise ValueError(
-                                f"Connectivity Graph marked as undirected\
-                                    but edges ({u}, {v}) and ({v}, {u}) have different supported\
-                                    gate sets."
-                            )
-
-        elif isinstance(gate_connectivity_graph, dict):
+        if isinstance(gate_connectivity_graph, dict):
             self._gate_connectivity_graph = DiGraph()
-            for edge, supported_gates in gate_connectivity_graph.items():
-                self._gate_connectivity_graph.add_edge(
-                    edge[0], edge[1], supported_gates=supported_gates
-                )
-                if not directed:
-                    back_edge = (edge[1], edge[0])
-                    if back_edge not in gate_connectivity_graph:
-                        self._gate_connectivity_graph.add_edge(
-                            edge[1], edge[0], supported_gates=supported_gates
-                        )
+            for (u, v), supported_gates in gate_connectivity_graph.items():
+                self._gate_connectivity_graph.add_edge(u, v, supported_gates=supported_gates)
+        elif isinstance(gate_connectivity_graph, DiGraph):
+            self._gate_connectivity_graph = gate_connectivity_graph
         else:
             raise TypeError(
                 "Gate_connectivity_graph must either be a dictionary of edges mapped to \
 supported gates lists, or a DiGraph with supported gates \
 provided as edge attributes."
             )
 
+        if not directed:
+            """
+            Add reverse edges and check that any supplied reverse edges have
+            identical supported gate sets to their corresponding forwards edge.
+            """
+            for u, v in self._gate_connectivity_graph.edges:
+                back_edge = (v, u)
+                if back_edge not in self._gate_connectivity_graph.edges:
+                    supported_gates = self._gate_connectivity_graph[u][v]["supported_gates"]
+                    self._gate_connectivity_graph.add_edge(
+                        *back_edge, supported_gates=supported_gates
+                    )
+                else:
+                    # check that the supported gate sets are identical
+                    if (
+                        self._gate_connectivity_graph[u][v]["supported_gates"]
+                        != self._gate_connectivity_graph[v][u]["supported_gates"]
+                    ):
+                        raise ValueError(
+                            f"Connectivity Graph marked as undirected\
+                                but edges ({u}, {v}) and ({v}, {u}) have different supported\
+                                gate sets."
+                        )
+
     def validate(self, circuit: Circuit) -> None:
         """
         Verifies that any multiqubit gates used within a verbatim box are supported

test/unit_tests/braket/emulation/test_gate_connectivity_criterion.py

@@ -155,7 +155,7 @@ def test_undirected_graph_construction_from_dict():
     """
     dict_representation = {
         (0, 1): ["CNot", "CZ"],
-        (1, 0): ["CZ", "XX"],
+        (1, 0): ["CNot", "CZ"],
         (1, 2): ["Swap", "CNot", "YY"],
         (0, 2): ["XX", "XY", "CNot", "CZ"],
         (2, 5): ["XX", "XY", "CNot", "CZ"],
@@ -167,7 +167,7 @@ def test_undirected_graph_construction_from_dict():
             (1, 2, {"supported_gates": ["Swap", "CNot", "YY"]}),
             (0, 2, {"supported_gates": ["XX", "XY", "CNot", "CZ"]}),
             (2, 5, {"supported_gates": ["XX", "XY", "CNot", "CZ"]}),
-            (1, 0, {"supported_gates": ["CZ", "XX"]}),
+            (1, 0, {"supported_gates": ["CNot", "CZ"]}),
             (2, 1, {"supported_gates": ["Swap", "CNot", "YY"]}),
             (2, 0, {"supported_gates": ["XX", "XY", "CNot", "CZ"]}),
             (5, 2, {"supported_gates": ["XX", "XY", "CNot", "CZ"]}),
@@ -289,3 +289,24 @@ def test_validate_instruction_method(gate_name, controls, targets, is_valid, bas
     else:
         with pytest.raises(ValueError):
             gcc.validate_instruction_connectivity(gate_name, controls, targets)
+
+
+@pytest.mark.parametrize(
+    "graph",
+    [
+        (
+            nx.from_dict_of_dicts(
+                {
+                    0: {1: {"supported_gates": ["cnot", "cz"]}},
+                    1: {0: {"supported_gates": ["cz", "cnot", "xx"]}},
+                },
+                create_using=nx.DiGraph(),
+            )
+        ),
+        ({(0, 1): ["cnot", "cz"], (1, 0): ["cz", "cnot", "xx"]}),
+        ({(0, 1): ["xx", "yy"], (1, 0): ["yy", "xx"]}),
+    ],
+)
+def test_invalid_undirected_graph(graph):
+    with pytest.raises(ValueError):
+        GateConnectivityCriterion(graph, directed=False)