def _evolve_subsystem(self, state, qargs):
        """Evolve a quantum state by the operator.

        Args:
            state (QuantumState): The input statevector or density matrix.
            qargs (list): a list of QuantumState subsystem positions to apply
                           the operator on.

        Returns:
            QuantumState: the output quantum state.

        Raises:
            QiskitError: if the operator dimension does not match the
            specified QuantumState subsystem dimensions.
        """
        mat = np.reshape(self.data, self._shape)
        # Hack to assume state is a N-qubit state until a proper class for states
        # is in place
        state_size = len(state)
        state_dims = self._automatic_dims(None, state_size)
        if self.input_dims() != len(qargs) * (2,):
            raise QiskitError(
                "Operator input dimensions are not compatible with state subsystem dimensions."
            )
        if state.ndim == 1:
            # Return evolved statevector
            tensor = np.reshape(state, state_dims)
            indices = [len(state_dims) - 1 - qubit for qubit in qargs]
            tensor = self._einsum_matmul(tensor, mat, indices)
            return np.reshape(tensor, state_size)
        # Return evolved density matrix
        tensor = np.reshape(state, 2 * state_dims)
        indices = [len(state_dims) - 1 - qubit for qubit in qargs]
        right_shift = len(state_dims)
        # Left multiply by operator
        tensor = self._einsum_matmul(tensor, mat, indices)
        # Right multiply by adjoint operator
        # We implement the transpose by doing left multiplication instead of right
        # in the _einsum_matmul function
        tensor = self._einsum_matmul(
            tensor, np.conj(mat), indices, shift=right_shift)
        return np.reshape(tensor, [state_size, state_size])
def _evolve_subsystem(self, state, qargs):
        """Evolve a quantum state by the operator.

        Args:
            state (QuantumState): The input statevector or density matrix.
            qargs (list): a list of QuantumState subsystem positions to apply
                           the operator on.

        Returns:
            QuantumState: the output quantum state.

        Raises:
            QiskitError: if the operator dimension does not match the
            specified QuantumState subsystem dimensions.
        """
        mat = np.reshape(self.data, self._shape)
        # Hack to assume state is a N-qubit state until a proper class for states
        # is in place
        state_size = len(state)
        state_dims = self._automatic_dims(None, state_size)
        if self.input_dims() != len(qargs) * (2,):
            raise QiskitError(
                "Operator input dimensions are not compatible with state subsystem dimensions."
            )
        if state.ndim == 1:
            # Return evolved statevector
            tensor = np.reshape(state, state_dims)
            indices = [len(state_dims) - 1 - qubit for qubit in qargs]
            tensor = self._einsum_matmul(tensor, mat, indices)
            return np.reshape(tensor, state_size)
        # Return evolved density matrix
        tensor = np.reshape(state, 2 * state_dims)
        indices = [len(state_dims) - 1 - qubit for qubit in qargs]
        right_shift = len(state_dims)
        # Left multiply by operator
        tensor = self._einsum_matmul(tensor, mat, indices)
        # Right multiply by adjoint operator
        # We implement the transpose by doing left multiplication instead of right
        # in the _einsum_matmul function
        tensor = self._einsum_matmul(
            tensor, np.conj(mat), indices, shift=right_shift)
        return np.reshape(tensor, [state_size, state_size])
def _evolve_subsystem ( self , state , qargs ) : mat = np . reshape ( self . data , self . _shape ) # Hack to assume state is a N-qubit state until a proper class for states # is in place state_size = len ( state ) state_dims = self . _automatic_dims ( None , state_size ) if self . input_dims ( ) != len ( qargs ) * ( 2 , ) : raise QiskitError ( "Operator input dimensions are not compatible with state subsystem dimensions." ) if state . ndim == 1 : # Return evolved statevector tensor = np . reshape ( state , state_dims ) indices = [ len ( state_dims ) - 1 - qubit for qubit in qargs ] tensor = self . _einsum_matmul ( tensor , mat , indices ) return np . reshape ( tensor , state_size ) # Return evolved density matrix tensor = np . reshape ( state , 2 * state_dims ) indices = [ len ( state_dims ) - 1 - qubit for qubit in qargs ] right_shift = len ( state_dims ) # Left multiply by operator tensor = self . _einsum_matmul ( tensor , mat , indices ) # Right multiply by adjoint operator # We implement the transpose by doing left multiplication instead of right # in the _einsum_matmul function tensor = self . _einsum_matmul ( tensor , np . conj ( mat ) , indices , shift = right_shift ) return np . reshape ( tensor , [ state_size , state_size ] )
Evolve a quantum state by the operator.

        Args:
            state (QuantumState): The input statevector or density matrix.
            qargs (list): a list of QuantumState subsystem positions to apply
                           the operator on.

        Returns:
            QuantumState: the output quantum state.

        Raises:
            QiskitError: if the operator dimension does not match the
            specified QuantumState subsystem dimensions.
Evolve a quantum state by the operator .