# Copyright 2018 The Cirq Developers
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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"""An optimizer that expands composite operations via `cirq.decompose`."""
from typing import Callable
from cirq import ops, protocols
from cirq.circuits.optimization_pass import (
PointOptimizer,
PointOptimizationSummary,
)
[docs]class ExpandComposite(PointOptimizer):
"""An optimizer that expands composite operations via `cirq.decompose`.
For each operation in the circuit, this pass examines if the operation can
be decomposed. If it can be, the operation is cleared out and and replaced
with its decomposition using a fixed insertion strategy.
"""
[docs] def __init__(self,
no_decomp: Callable[[ops.Operation], bool]=(lambda _: False)
) -> None:
"""Construct the optimization pass.
Args:
no_decomp: A predicate that determines whether an operation should
be decomposed or not. Defaults to decomposing everything.
"""
super().__init__()
self.no_decomp = no_decomp
[docs] def optimization_at(self, circuit, index, op):
decomposition = protocols.decompose(op,
keep=self.no_decomp,
on_stuck_raise=None)
if decomposition == [op]:
return None
return PointOptimizationSummary(
clear_span=1,
clear_qubits=op.qubits,
new_operations=decomposition)