# This code is part of Qiskit.
#
# (C) Copyright IBM 2017, 2019.
#
# 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.

"""Calculate the width of a DAG circuit."""

from qiskit.transpiler.basepasses import AnalysisPass


class Width(AnalysisPass):
    """Calculate the width of a DAG circuit.

    The result is saved in ``property_set['width']`` as an integer that
    contains the number of qubits + the number of clbits.
    """

    def run(self, dag):
        """Run the Width pass on `dag`."""
        self.property_set["width"] = dag.width()