Source code for qiskit.circuit.classicalregister

# This code is part of Qiskit.
# (C) Copyright IBM 2017.
# 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
# Any modifications or derivative works of this code must retain this
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# that they have been altered from the originals.

# pylint: disable=bad-docstring-quotes

Classical register reference object.
import itertools

from qiskit.circuit.exceptions import CircuitError

from qiskit.utils.deprecation import deprecate_func
from .register import Register
from .bit import Bit

[docs]class Clbit(Bit): """Implement a classical bit.""" __slots__ = () def __init__(self, register=None, index=None): """Creates a classical bit. Args: register (ClassicalRegister): Optional. A classical register containing the bit. index (int): Optional. The index of the bit in its containing register. Raises: CircuitError: if the provided register is not a valid :class:`ClassicalRegister` """ if register is None or isinstance(register, ClassicalRegister): super().__init__(register, index) else: raise CircuitError( "Clbit needs a ClassicalRegister and %s was provided" % type(register).__name__ )
[docs]class ClassicalRegister(Register): """Implement a classical register.""" # Counter for the number of instances in this class. instances_counter = itertools.count() # Prefix to use for auto naming. prefix = "c" bit_type = Clbit
[docs] @deprecate_func( additional_msg=( "Correct exporting to OpenQASM 2 is the responsibility of a larger exporter; it cannot " "safely be done on an object-by-object basis without context. No replacement will be " "provided, because the premise is wrong." ), since="0.23.0", ) def qasm(self): """Return OPENQASM string for this register.""" return "creg %s[%d];" % (, self.size)