feat: add connectivity to transpile (#188)

qiskit_braket_provider/providers/adapter.py

@@ -409,6 +409,7 @@ def to_braket(
     circuit: QuantumCircuit,
     basis_gates: Optional[Iterable[str]] = None,
     verbatim: bool = False,
+    connectivity: Optional[list[list[int]]] = None,
 ) -> Circuit:
     """Return a Braket quantum circuit from a Qiskit quantum circuit.
 
@@ -419,6 +420,8 @@ def to_braket(
             Default: `None`.
         verbatim (bool): Whether to translate the circuit without any modification, in other
             words without transpiling it. Default: False.
+        connectivity (Optional[list[list[int]]): If provided, will transpile to a circuit
+            with this connectivity. Default: `None`.
 
     Returns:
         Circuit: Braket circuit
@@ -429,10 +432,16 @@ def to_braket(
     basis_gates = set(basis_gates or _TRANSLATABLE_QISKIT_GATE_NAMES)
 
     braket_circuit = Circuit()
-    if not verbatim and not {gate.name for gate, _, _ in circuit.data}.issubset(
-        basis_gates
-    ):
-        circuit = transpile(circuit, basis_gates=basis_gates, optimization_level=0)
+    needs_transpilation = connectivity or not {
+        gate.name for gate, _, _ in circuit.data
+    }.issubset(basis_gates)
+    if not verbatim and needs_transpilation:
+        circuit = transpile(
+            circuit,
+            basis_gates=basis_gates,
+            coupling_map=connectivity,
+            optimization_level=0,
+        )
 
     # Verify that ParameterVector would not collide with scalar variables after renaming.
     _validate_name_conflicts(circuit.parameters)

tests/providers/test_adapter.py

@@ -538,6 +538,44 @@ def test_get_controlled_gateset(self):
             "mcx",
         }
 
+    def test_connectivity(self):
+        """Tests transpiling with connectivity"""
+        qiskit_circuit = QuantumCircuit(3)
+        qiskit_circuit.h(0)
+        qiskit_circuit.cx(0, 1)
+        qiskit_circuit.rxx(0.1, 0, 2)
+        connectivity = [[0, 1], [1, 0], [1, 2], [2, 1]]
+
+        braket_circuit = to_braket(qiskit_circuit, connectivity=connectivity)
+        braket_circuit_unconnected = to_braket(qiskit_circuit)
+        braket_circuit_verbatim = to_braket(
+            qiskit_circuit, verbatim=True, connectivity=connectivity
+        )
+
+        def gate_matches_connectivity(gate) -> bool:
+            return any(
+                (
+                    gate.target.union(gate.control).issubset(adjacency)
+                    for adjacency in connectivity
+                )
+            )
+
+        assert all(
+            (gate_matches_connectivity(gate) for gate in braket_circuit.instructions)
+        )
+        assert not all(
+            (
+                gate_matches_connectivity(gate)
+                for gate in braket_circuit_unconnected.instructions
+            )
+        )
+        assert not all(
+            (
+                gate_matches_connectivity(gate)
+                for gate in braket_circuit_verbatim.instructions
+            )
+        )
+
 
 class TestFromBraket(TestCase):
     """Test Braket circuit conversion."""