C贸digo fuente para qiskit.transpiler.passes.utils.gate_direction

# This code is part of Qiskit.
#
# (C) Copyright IBM 2017, 2021.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""Rearrange the direction of the cx nodes to match the directed coupling map."""

from math import pi

from qiskit.transpiler.basepasses import TransformationPass
from qiskit.transpiler.exceptions import TranspilerError

from qiskit.converters import dag_to_circuit, circuit_to_dag
from qiskit.circuit import QuantumRegister, ControlFlowOp
from qiskit.dagcircuit import DAGCircuit, DAGOpNode
from qiskit.circuit.library.standard_gates import (
    RYGate,
    HGate,
    CXGate,
    CZGate,
    ECRGate,
    RXXGate,
    RYYGate,
    RZZGate,
    RZXGate,
    SwapGate,
)


def _swap_node_qargs(node):
    return DAGOpNode(node.op, node.qargs[::-1], node.cargs)


[documentos]class GateDirection(TransformationPass): """Modify asymmetric gates to match the hardware coupling direction. This pass makes use of the following identities:: 鈹屸攢鈹鈹鈹愨攲鈹鈹鈹鈹愨攲鈹鈹鈹鈹 q_0: 鈹鈹鈻犫攢鈹 q_0: 鈹 H 鈹溾敜 X 鈹溾敜 H 鈹 鈹屸攢鈹粹攢鈹 = 鈹溾攢鈹鈹鈹も敂鈹鈹攢鈹樷敎鈹鈹鈹鈹 q_1: 鈹 X 鈹 q_1: 鈹 H 鈹溾攢鈹鈻犫攢鈹鈹 H 鈹 鈹斺攢鈹鈹鈹 鈹斺攢鈹鈹鈹 鈹斺攢鈹鈹鈹 鈹屸攢鈹鈹鈹鈹鈹鈹 鈹屸攢鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹愨攲鈹鈹鈹鈹鈹鈹鈹愨攲鈹鈹鈹鈹 q_0: 鈹0 鈹 q_0: 鈹 RY(-pi/2) 鈹溾敜1 鈹溾敜 H 鈹 鈹 ECR 鈹 = 鈹斺敩鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹も攤 ECR 鈹傗敎鈹鈹鈹鈹 q_1: 鈹1 鈹 q_1: 鈹鈹 RY(pi/2) 鈹溾敜0 鈹溾敜 H 鈹 鈹斺攢鈹鈹鈹鈹鈹鈹 鈹斺攢鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹 鈹屸攢鈹鈹鈹鈹鈹鈹 鈹屸攢鈹鈹鈹愨攲鈹鈹鈹鈹鈹鈹鈹愨攲鈹鈹鈹鈹 q_0: 鈹0 鈹 q_0: 鈹 H 鈹溾敜1 鈹溾敜 H 鈹 鈹 RZX 鈹 = 鈹溾攢鈹鈹鈹も攤 RZX 鈹傗敎鈹鈹鈹鈹 q_1: 鈹1 鈹 q_1: 鈹 H 鈹溾敜0 鈹溾敜 H 鈹 鈹斺攢鈹鈹鈹鈹鈹鈹 鈹斺攢鈹鈹鈹樷敂鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹 This pass assumes that the positions of the qubits in the :attr:`.DAGCircuit.qubits` attribute are the physical qubit indicies. For example if ``dag.qubits[0]`` is qubit 0 in the :class:`.CouplingMap` or :class:`.Target`. """ _KNOWN_REPLACEMENTS = frozenset(["cx", "cz", "ecr", "swap", "rzx", "rxx", "ryy", "rzz"]) def __init__(self, coupling_map, target=None): """GateDirection pass. Args: coupling_map (CouplingMap): Directed graph represented a coupling map. target (Target): The backend target to use for this pass. If this is specified it will be used instead of the coupling map """ super().__init__() self.coupling_map = coupling_map self.target = target # Create the replacement dag and associated register. self._cx_dag = DAGCircuit() qr = QuantumRegister(2) self._cx_dag.add_qreg(qr) self._cx_dag.apply_operation_back(HGate(), [qr[0]], []) self._cx_dag.apply_operation_back(HGate(), [qr[1]], []) self._cx_dag.apply_operation_back(CXGate(), [qr[1], qr[0]], []) self._cx_dag.apply_operation_back(HGate(), [qr[0]], []) self._cx_dag.apply_operation_back(HGate(), [qr[1]], []) self._ecr_dag = DAGCircuit() qr = QuantumRegister(2) self._ecr_dag.add_qreg(qr) self._ecr_dag.apply_operation_back(RYGate(-pi / 2), [qr[0]], []) self._ecr_dag.apply_operation_back(RYGate(pi / 2), [qr[1]], []) self._ecr_dag.apply_operation_back(ECRGate(), [qr[1], qr[0]], []) self._ecr_dag.apply_operation_back(HGate(), [qr[0]], []) self._ecr_dag.apply_operation_back(HGate(), [qr[1]], []) self._cz_dag = DAGCircuit() qr = QuantumRegister(2) self._cz_dag.add_qreg(qr) self._cz_dag.apply_operation_back(CZGate(), [qr[1], qr[0]], []) self._swap_dag = DAGCircuit() qr = QuantumRegister(2) self._swap_dag.add_qreg(qr) self._swap_dag.apply_operation_back(SwapGate(), [qr[1], qr[0]], []) # If adding more replacements (either static or dynamic), also update the class variable # `_KNOWN_REPLACMENTS` to include them in the error messages. self._static_replacements = { "cx": self._cx_dag, "cz": self._cz_dag, "ecr": self._ecr_dag, "swap": self._swap_dag, } @staticmethod def _rzx_dag(parameter): _rzx_dag = DAGCircuit() qr = QuantumRegister(2) _rzx_dag.add_qreg(qr) _rzx_dag.apply_operation_back(HGate(), [qr[0]], []) _rzx_dag.apply_operation_back(HGate(), [qr[1]], []) _rzx_dag.apply_operation_back(RZXGate(parameter), [qr[1], qr[0]], []) _rzx_dag.apply_operation_back(HGate(), [qr[0]], []) _rzx_dag.apply_operation_back(HGate(), [qr[1]], []) return _rzx_dag @staticmethod def _rxx_dag(parameter): _rxx_dag = DAGCircuit() qr = QuantumRegister(2) _rxx_dag.add_qreg(qr) _rxx_dag.apply_operation_back(RXXGate(parameter), [qr[1], qr[0]], []) return _rxx_dag @staticmethod def _ryy_dag(parameter): _ryy_dag = DAGCircuit() qr = QuantumRegister(2) _ryy_dag.add_qreg(qr) _ryy_dag.apply_operation_back(RYYGate(parameter), [qr[1], qr[0]], []) return _ryy_dag @staticmethod def _rzz_dag(parameter): _rzz_dag = DAGCircuit() qr = QuantumRegister(2) _rzz_dag.add_qreg(qr) _rzz_dag.apply_operation_back(RZZGate(parameter), [qr[1], qr[0]], []) return _rzz_dag def _run_coupling_map(self, dag, wire_map, edges=None): if edges is None: edges = set(self.coupling_map.get_edges()) if not edges: return dag # Don't include directives to avoid things like barrier, which are assumed always supported. for node in dag.op_nodes(include_directives=False): if isinstance(node.op, ControlFlowOp): node.op = node.op.replace_blocks( dag_to_circuit( self._run_coupling_map( circuit_to_dag(block), { inner: wire_map[outer] for outer, inner in zip(node.qargs, block.qubits) }, edges, ) ) for block in node.op.blocks ) continue if len(node.qargs) != 2: continue if dag.has_calibration_for(node): continue qargs = (wire_map[node.qargs[0]], wire_map[node.qargs[1]]) if qargs not in edges and (qargs[1], qargs[0]) not in edges: raise TranspilerError( f"The circuit requires a connection between physical qubits {qargs}" ) if qargs not in edges: replacement = self._static_replacements.get(node.name) if replacement is not None: dag.substitute_node_with_dag(node, replacement) elif node.name == "rzx": dag.substitute_node_with_dag(node, self._rzx_dag(*node.op.params)) elif node.name == "rxx": dag.substitute_node_with_dag(node, self._rxx_dag(*node.op.params)) elif node.name == "ryy": dag.substitute_node_with_dag(node, self._ryy_dag(*node.op.params)) elif node.name == "rzz": dag.substitute_node_with_dag(node, self._rzz_dag(*node.op.params)) else: raise TranspilerError( f"'{node.name}' would be supported on '{qargs}' if the direction were" f" swapped, but no rules are known to do that." f" {list(self._KNOWN_REPLACEMENTS)} can be automatically flipped." ) return dag def _run_target(self, dag, wire_map): # Don't include directives to avoid things like barrier, which are assumed always supported. for node in dag.op_nodes(include_directives=False): if isinstance(node.op, ControlFlowOp): node.op = node.op.replace_blocks( dag_to_circuit( self._run_target( circuit_to_dag(block), { inner: wire_map[outer] for outer, inner in zip(node.qargs, block.qubits) }, ) ) for block in node.op.blocks ) continue if len(node.qargs) != 2: continue if dag.has_calibration_for(node): continue qargs = (wire_map[node.qargs[0]], wire_map[node.qargs[1]]) swapped = (qargs[1], qargs[0]) if node.name in self._static_replacements: if self.target.instruction_supported(node.name, qargs): continue if self.target.instruction_supported(node.name, swapped): dag.substitute_node_with_dag(node, self._static_replacements[node.name]) else: raise TranspilerError( f"The circuit requires a connection between physical qubits {qargs}" f" for {node.name}" ) elif node.name == "rzx": if self.target.instruction_supported( qargs=qargs, operation_class=RZXGate, parameters=node.op.params ): continue if self.target.instruction_supported( qargs=swapped, operation_class=RZXGate, parameters=node.op.params ): dag.substitute_node_with_dag(node, self._rzx_dag(*node.op.params)) else: raise TranspilerError( f"The circuit requires a connection between physical qubits {qargs}" f" for {node.name}" ) elif node.name == "rxx": if self.target.instruction_supported( qargs=qargs, operation_class=RXXGate, parameters=node.op.params ): continue if self.target.instruction_supported( qargs=swapped, operation_class=RXXGate, parameters=node.op.params ): dag.substitute_node_with_dag(node, self._rxx_dag(*node.op.params)) else: raise TranspilerError( f"The circuit requires a connection between physical qubits {qargs}" f" for {node.name}" ) elif node.name == "ryy": if self.target.instruction_supported( qargs=qargs, operation_class=RYYGate, parameters=node.op.params ): continue if self.target.instruction_supported( qargs=swapped, operation_class=RYYGate, parameters=node.op.params ): dag.substitute_node_with_dag(node, self._ryy_dag(*node.op.params)) else: raise TranspilerError( f"The circuit requires a connection between physical qubits {qargs}" f" for {node.name}" ) elif node.name == "rzz": if self.target.instruction_supported( qargs=qargs, operation_class=RZZGate, parameters=node.op.params ): continue if self.target.instruction_supported( qargs=swapped, operation_class=RZZGate, parameters=node.op.params ): dag.substitute_node_with_dag(node, self._rzz_dag(*node.op.params)) else: raise TranspilerError( f"The circuit requires a connection between physical qubits {qargs}" f" for {node.name}" ) elif self.target.instruction_supported(node.name, qargs): continue elif self.target.instruction_supported(node.name, swapped) or dag.has_calibration_for( _swap_node_qargs(node) ): raise TranspilerError( f"'{node.name}' would be supported on '{qargs}' if the direction were" f" swapped, but no rules are known to do that." f" {list(self._KNOWN_REPLACEMENTS)} can be automatically flipped." ) else: raise TranspilerError( f"'{node.name}' with parameters '{node.op.params}' is not supported on qubits" f" '{qargs}' in either direction." ) return dag
[documentos] def run(self, dag): """Run the GateDirection pass on `dag`. Flips the cx nodes to match the directed coupling map. Modifies the input dag. Args: dag (DAGCircuit): DAG to map. Returns: DAGCircuit: The rearranged dag for the coupling map Raises: TranspilerError: If the circuit cannot be mapped just by flipping the cx nodes. """ layout_map = {bit: i for i, bit in enumerate(dag.qubits)} if self.target is None: return self._run_coupling_map(dag, layout_map) return self._run_target(dag, layout_map)