improved to_bracket qiskit-community#176

qiskit_braket_provider/providers/braket_provider.py

@@ -3,10 +3,14 @@
 import warnings
 
 from braket.aws import AwsDevice
+from braket.circuits import Circuit as BraketCircuit
 from braket.device_schema.dwave import DwaveDeviceCapabilities
 from braket.device_schema.quera import QueraDeviceCapabilities
 from braket.device_schema.xanadu import XanaduDeviceCapabilities
+from qiskit.circuit import Gate
 from qiskit.providers import ProviderV1
+from qiskit.transpiler import CouplingMap, PassManager
+from qiskit.transpiler.passes import BasicSwap
 
 from .braket_backend import BraketAwsBackend, BraketLocalBackend
 
@@ -82,3 +86,182 @@ def __init__(self):
             stacklevel=2,
         )
         super().__init__()
+
+    def to_braket(self, circuit, backend, native=True, topology=True):
+        """
+        Convert a Qiskit circuit to a Braket circuit respecting backend restrictions.
+
+        Args:
+            circuit (QuantumCircuit): The input Qiskit circuit.
+            backend (BraketBackend): The backend to which the circuit will be transpiled.
+            native (bool): Whether to use only native gates of the backend.
+            topology (bool): Whether to respect the device topology.
+
+        Returns:
+            BraketCircuit: The converted Braket circuit.
+        """
+        if native:
+            # Adjust angles and gate types based on backend restrictions
+            circuit = self.adjust_angles(circuit, backend)
+            if topology:
+                circuit = self.adjust_topology(circuit, backend)
+
+        # Convert the adjusted Qiskit circuit to a Braket circuit
+        braket_circuit = self.convert_to_braket(circuit)
+
+        return braket_circuit
+
+    def adjust_angles(self, circuit, backend):
+        """
+        Adjust angles in the Qiskit circuit based on backend angle restrictions.
+
+        Args:
+            circuit (QuantumCircuit): The input Qiskit circuit.
+            backend (BraketBackend): The backend to which the circuit will be transpiled.
+
+        Returns:
+            QuantumCircuit: The adjusted Qiskit circuit.
+        """
+        if backend.name.startswith("rigetti"):
+            # Adjust angles for Rigetti backends
+            for instr, _, _ in circuit.data:
+                if isinstance(instr, Gate) and instr.name == "rx":
+                    # Adjust angles to supported values
+                    theta = instr.params[0]
+                    new_theta = self.adjust_angle(theta)
+                    instr.params[0] = new_theta
+        # Add more angle adjustments for other backends as needed
+        return circuit
+
+    def adjust_angle(self, theta):
+        """
+        Adjust the angle to be within the supported range of the backend.
+
+        Args:
+            theta (float): The original angle.
+
+        Returns:
+            float: The adjusted angle.
+        """
+        # Adjust the angle to supported values
+        supported_angles = [0, -1 / 2, 1 / 2, -1, 1]  # Example for Rigetti backend
+        closest_angle = min(supported_angles, key=lambda x: abs(x - theta))
+        return closest_angle
+
+    def adjust_topology(self, circuit, backend):
+        """
+        Adjust the Qiskit circuit to respect the device topology of the backend.
+
+        Args:
+            circuit (QuantumCircuit): The input Qiskit circuit.
+            backend (BraketBackend): The backend to which the circuit will be transpiled.
+
+        Returns:
+            QuantumCircuit: The adjusted Qiskit circuit.
+        """
+        # Get the coupling map of the backend
+        coupling_map = CouplingMap(backend.configuration().coupling_map)
+
+        # Create a pass manager with the BasicSwap pass to adjust for the topology
+        pass_manager = PassManager()
+        pass_manager.append(BasicSwap(coupling_map))
+
+        # Run the pass manager on the circuit
+        adjusted_circuit = pass_manager.run(circuit)
+
+        return adjusted_circuit
+
+    def convert_to_braket(self, circuit):
+        """
+        Convert the Qiskit circuit to a Braket circuit.
+
+        Args:
+            circuit (QuantumCircuit): The input Qiskit circuit.
+
+        Returns:
+            BraketCircuit: The converted Braket circuit.
+        """
+        braket_circuit = BraketCircuit()
+
+        for instr, qargs, _ in circuit.data:
+            if isinstance(instr, Gate):
+                if instr.name == "h":
+                    braket_circuit.h(qargs[0].index)
+                elif instr.name == "x":
+                    braket_circuit.x(qargs[0].index)
+                elif instr.name == "y":
+                    braket_circuit.y(qargs[0].index)
+                elif instr.name == "z":
+                    braket_circuit.z(qargs[0].index)
+                elif instr.name == "s":
+                    braket_circuit.s(qargs[0].index)
+                elif instr.name == "sdg":
+                    braket_circuit.si(qargs[0].index)
+                elif instr.name == "t":
+                    braket_circuit.t(qargs[0].index)
+                elif instr.name == "tdg":
+                    braket_circuit.ti(qargs[0].index)
+                elif instr.name == "rx":
+                    theta = instr.params[0]
+                    braket_circuit.rx(theta, qargs[0].index)
+                elif instr.name == "ry":
+                    theta = instr.params[0]
+                    braket_circuit.ry(theta, qargs[0].index)
+                elif instr.name == "rz":
+                    theta = instr.params[0]
+                    braket_circuit.rz(theta, qargs[0].index)
+                elif instr.name == "u1":
+                    lambda_ = instr.params[0]
+                    braket_circuit.phaseshift(lambda_, qargs[0].index)
+                elif instr.name == "u2":
+                    phi, lambda_ = instr.params
+                    braket_circuit.u2(phi, lambda_, qargs[0].index)
+                elif instr.name == "u3":
+                    theta, phi, lambda_ = instr.params
+                    braket_circuit.u3(theta, phi, lambda_, qargs[0].index)
+                elif instr.name == "cx":
+                    control, target = qargs
+                    braket_circuit.cnot(control.index, target.index)
+                elif instr.name == "cy":
+                    control, target = qargs
+                    braket_circuit.cy(control.index, target.index)
+                elif instr.name == "cz":
+                    control, target = qargs
+                    braket_circuit.cz(control.index, target.index)
+                elif instr.name == "ch":
+                    control, target = qargs
+                    braket_circuit.ch(control.index, target.index)
+                elif instr.name == "crx":
+                    theta = instr.params[0]
+                    control, target = qargs
+                    braket_circuit.crx(theta, control.index, target.index)
+                elif instr.name == "cry":
+                    theta = instr.params[0]
+                    control, target = qargs
+                    braket_circuit.cry(theta, control.index, target.index)
+                elif instr.name == "crz":
+                    theta = instr.params[0]
+                    control, target = qargs
+                    braket_circuit.crz(theta, control.index, target.index)
+                elif instr.name == "cp":
+                    lambda_ = instr.params[0]
+                    control, target = qargs
+                    braket_circuit.cphaseshift(lambda_, control.index, target.index)
+                elif instr.name == "cu1":
+                    lambda_ = instr.params[0]
+                    control, target = qargs
+                    braket_circuit.cphaseshift(lambda_, control.index, target.index)
+                elif instr.name == "cu3":
+                    theta, phi, lambda_ = instr.params
+                    control, target = qargs
+                    braket_circuit.cu3(theta, phi, lambda_, control.index, target.index)
+                elif instr.name == "swap":
+                    q0, q1 = qargs
+                    braket_circuit.swap(q0.index, q1.index)
+                elif instr.name == "ccx":
+                    control1, control2, target = qargs
+                    braket_circuit.ccnot(control1.index, control2.index, target.index)
+                else:
+                    raise ValueError(f"Unsupported gate: {instr.name}")
+
+        return braket_circuit