# Source code for mimiqcircuits.operations.barrier

```
#
# Copyright © 2022-2023 University of Strasbourg. All Rights Reserved.
#
# 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
#
# http://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,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from mimiqcircuits.operations.operation import Operation
import mimiqcircuits.lazy as lz
[docs]
class Barrier(Operation):
"""Barrier operation.
A barrier is a special operation that does not affect the quantum state or
the execution of a circuit, but it prevents compression or optimization
operation from being applied across it.
Examples:
Adding Barrier operation to the Circuit (The args can be: range, list,
tuple, set or int)
>>> from mimiqcircuits import *
>>> c= Circuit()
>>> c.push(Barrier(1), 1)
2-qubit circuit with 1 instructions:
└── Barrier @ q[1]
<BLANKLINE>
>>> from mimiqcircuits import *
>>> c= Circuit()
>>> c.push(Barrier(1), range(0,4))
4-qubit circuit with 4 instructions:
├── Barrier @ q[0]
├── Barrier @ q[1]
├── Barrier @ q[2]
└── Barrier @ q[3]
<BLANKLINE>
Adding Barrier to the circuit as a multi-qubits gate
>>> from mimiqcircuits import *
>>> c= Circuit()
>>> c.push(Barrier(5),1,2,3,4,5)
6-qubit circuit with 1 instructions:
└── Barrier @ q[1,2,3,4,5]
<BLANKLINE>
"""
_name = "Barrier"
_num_qubits = None
_num_bits = 0
def __init__(self, num_qubits):
"""
Initialize a barrier operation
Args:
num_qubits: number of qubits the barrier will cover
Raises:
ValueError: if num_qubits is less than 1
"""
super().__init__()
if num_qubits < 1:
raise ValueError("Number of qubits must be greater than 0")
self._num_qubits = num_qubits
self._qregsizes = [num_qubits]
def __new__(self, *args):
if len(args) == 0:
return lz.LazyExpr(Barrier, lz.LazyArg())
elif len(args) == 1:
return object.__new__(self)
else:
raise ValueError("Invalid number of arguments.")
# export operations
__all__ = ["Barrier"]
```