def _add(self, other, qargs=None):
"""Return the QuantumChannel self + other.
If ``qargs`` are specified the other channel will be added
assuming it is the identity channel on all other subsystems.
Args:
other (QuantumChannel): a quantum channel.
qargs (None or list): optional subsystems to add on
(Default: None)
Returns:
QuantumChannel: the linear addition self + other as a SuperOp object.
Raises:
QiskitError: if other cannot be converted to a channel or
has incompatible dimensions.
"""
# NOTE: this method must be overriden for subclasses
# that don't have a linear matrix representation
# ie Kraus and Stinespring
if qargs is None:
qargs = getattr(other, 'qargs', None)
if not isinstance(other, self.__class__):
other = self.__class__(other)
self._validate_add_dims(other, qargs)
other = ScalarOp._pad_with_identity(self, other, qargs)
ret = copy.copy(self)
ret._data = self._data + other._data
return ret
def _add(self, other, qargs=None):
"""Return the operator self + other.
If ``qargs`` are specified the other operator will be added
assuming it is identity on all other subsystems.
Args:
other (Operator): an operator object.
qargs (None or list): optional subsystems to add on
(Default: None)
Returns:
Operator: the operator self + other.
Raises:
QiskitError: if other is not an operator, or has incompatible
dimensions.
"""
# pylint: disable=cyclic-import
from qiskit.quantum_info.operators.scalar_op import ScalarOp
if qargs is None:
qargs = getattr(other, 'qargs', None)
if not isinstance(other, Operator):
other = Operator(other)
self._op_shape._validate_add(other._op_shape, qargs)
other = ScalarOp._pad_with_identity(self, other, qargs)
ret = copy.copy(self)
ret._data = self.data + other.data
return ret
def _add(self, other, qargs=None):
# NOTE: this method must be overridden for subclasses
# that don't have a linear matrix representation
# ie Kraus and Stinespring
if not isinstance(other, type(self)):
other = type(self)(other)
self._op_shape._validate_add(other._op_shape, qargs)
other = ScalarOp._pad_with_identity(self, other, qargs)
ret = copy.copy(self)
ret._data = self._data + other._data
return ret