# Source code for qiskit.circuit.measure

# 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 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.
"""
Quantum measurement in the computational basis.
"""
from qiskit.circuit.instruction import Instruction
from qiskit.circuit.quantumcircuit import QuantumCircuit
from qiskit.circuit.exceptions import CircuitError
[docs]class Measure(Instruction):
"""Quantum measurement in the computational basis."""
def __init__(self):
"""Create new measurement instruction."""
super().__init__("measure", 1, 1, [])
[docs] def broadcast_arguments(self, qargs, cargs):
qarg = qargs[0]
carg = cargs[0]
if len(carg) == len(qarg):
for qarg, carg in zip(qarg, carg):
yield [qarg], [carg]
elif len(qarg) == 1 and carg:
for each_carg in carg:
yield qarg, [each_carg]
else:
raise CircuitError("register size error")
def measure(self, qubit, cbit):
"""Measure quantum bit into classical bit (tuples).
Args:
qubit (QuantumRegister|list|tuple): quantum register
cbit (ClassicalRegister|list|tuple): classical register
Returns:
qiskit.Instruction: the attached measure instruction.
Raises:
CircuitError: if qubit is not in this circuit or bad format;
if cbit is not in this circuit or not creg.
"""
return self.append(Measure(), [qubit], [cbit])
QuantumCircuit.measure = measure