Source code for qiskit.circuit.controlflow.break_loop

# This code is part of Qiskit.
# (C) Copyright IBM 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
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"Circuit operation representing a ``break`` from a loop."

from typing import Optional

from qiskit.circuit.instruction import Instruction
from .builder import InstructionPlaceholder, InstructionResources

[docs]class BreakLoopOp(Instruction): """A circuit operation which, when encountered, jumps to the end of the nearest enclosing loop. .. note: Can be inserted only within the body of a loop op, and must span the full width of that block. **Circuit symbol:** .. parsed-literal:: ┌──────────────┐ q_0: ┤0 ├ │ │ q_1: ┤1 ├ │ break_loop │ q_2: ┤2 ├ │ │ c_0: ╡0 ╞ └──────────────┘ """ def __init__(self, num_qubits: int, num_clbits: int, label: Optional[str] = None): super().__init__("break_loop", num_qubits, num_clbits, [], label=label)
class BreakLoopPlaceholder(InstructionPlaceholder): """A placeholder instruction for use in control-flow context managers, when the number of qubits and clbits is not yet known. .. warning:: This is an internal interface and no part of it should be relied upon outside of Qiskit Terra. """ def __init__(self, *, label: Optional[str] = None): super().__init__("break_loop", 0, 0, [], label=label) def concrete_instruction(self, qubits, clbits): return ( self._copy_mutable_properties(BreakLoopOp(len(qubits), len(clbits), label=self.label)), InstructionResources(qubits=tuple(qubits), clbits=tuple(clbits)), ) def placeholder_resources(self): return InstructionResources()