qiskit/quantum_info/operators/channel/chi.py
def compose(self, other, qargs=None, front=False):
        """Return the composition channel self∘other.

        Args:
            other (QuantumChannel): a quantum channel.
            qargs (list): a list of subsystem positions to compose other on.
            front (bool): If False compose in standard order other(self(input))
                          otherwise compose in reverse order self(other(input))
                          [default: False]

        Returns:
            Chi: The composition channel as a Chi object.

        Raises:
            QiskitError: if other is not a QuantumChannel subclass, or
            has incompatible dimensions.
        """
        if qargs is not None:
            return Chi(
                SuperOp(self).compose(other, qargs=qargs, front=front))

        # Convert other to Choi since we convert via Choi
        if not isinstance(other, Choi):
            other = Choi(other)
        # Check dimensions match up
        if front and self._input_dim != other._output_dim:
            raise QiskitError(
                'input_dim of self must match output_dim of other')
        if not front and self._output_dim != other._input_dim:
            raise QiskitError(
                'input_dim of other must match output_dim of self')
        # Since we cannot directly add two channels in the Chi
        # representation we convert to the Choi representation
        return Chi(Choi(self).compose(other, front=front))
def compose(self, other, qargs=None, front=False):
        """Return the composition channel self∘other.

        Args:
            other (QuantumChannel): a quantum channel.
            qargs (list): a list of subsystem positions to compose other on.
            front (bool): If False compose in standard order other(self(input))
                          otherwise compose in reverse order self(other(input))
                          [default: False]

        Returns:
            Chi: The composition channel as a Chi object.

        Raises:
            QiskitError: if other is not a QuantumChannel subclass, or
            has incompatible dimensions.
        """
        if qargs is not None:
            return Chi(
                SuperOp(self).compose(other, qargs=qargs, front=front))

        # Convert other to Choi since we convert via Choi
        if not isinstance(other, Choi):
            other = Choi(other)
        # Check dimensions match up
        if front and self._input_dim != other._output_dim:
            raise QiskitError(
                'input_dim of self must match output_dim of other')
        if not front and self._output_dim != other._input_dim:
            raise QiskitError(
                'input_dim of other must match output_dim of self')
        # Since we cannot directly add two channels in the Chi
        # representation we convert to the Choi representation
        return Chi(Choi(self).compose(other, front=front))
def compose ( self , other , qargs = None , front = False ) : if qargs is not None : return Chi ( SuperOp ( self ) . compose ( other , qargs = qargs , front = front ) ) # Convert other to Choi since we convert via Choi if not isinstance ( other , Choi ) : other = Choi ( other ) # Check dimensions match up if front and self . _input_dim != other . _output_dim : raise QiskitError ( 'input_dim of self must match output_dim of other' ) if not front and self . _output_dim != other . _input_dim : raise QiskitError ( 'input_dim of other must match output_dim of self' ) # Since we cannot directly add two channels in the Chi # representation we convert to the Choi representation return Chi ( Choi ( self ) . compose ( other , front = front ) )
Return the composition channel self∘other.

        Args:
            other (QuantumChannel): a quantum channel.
            qargs (list): a list of subsystem positions to compose other on.
            front (bool): If False compose in standard order other(self(input))
                          otherwise compose in reverse order self(other(input))
                          [default: False]

        Returns:
            Chi: The composition channel as a Chi object.

        Raises:
            QiskitError: if other is not a QuantumChannel subclass, or
            has incompatible dimensions.
Return the composition channel self∘other .