Source code for cvxpy.atoms.affine.conj

"""
Copyright 2013 Steven Diamond

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 typing import List, Tuple

import numpy as np

import cvxpy.lin_ops.lin_op as lo
from cvxpy.atoms.affine.affine_atom import AffAtom
from cvxpy.constraints.constraint import Constraint


class conj(AffAtom):
    """Complex conjugate.
    """
    def __init__(self, expr) -> None:
        super(conj, self).__init__(expr)

    def numeric(self, values):
        """Convert the vector constant into a diagonal matrix.
        """
        return np.conj(values[0])

    def shape_from_args(self) -> Tuple[int, ...]:
        """Returns the shape of the expression.
        """
        return self.args[0].shape

    def is_incr(self, idx) -> bool:
        """Is the composition non-decreasing in argument idx?
        """
        return False

    def is_decr(self, idx) -> bool:
        """Is the composition non-increasing in argument idx?
        """
        return False

    def is_symmetric(self) -> bool:
        """Is the expression symmetric?
        """
        return self.args[0].is_symmetric()

    def is_hermitian(self) -> bool:
        """Is the expression Hermitian?
        """
        return self.args[0].is_hermitian()

    def graph_implementation(
        self, arg_objs, shape: Tuple[int, ...], data=None
    ) -> Tuple[lo.LinOp, List[Constraint]]:
        """Multiply the linear expressions.

        Parameters
        ----------
        arg_objs : list
            LinExpr for each argument.
        shape : tuple
            The shape of the resulting expression.
        data :
            Additional data required by the atom.

        Returns
        -------
        tuple
            (LinOp for objective, list of constraints)
        """
        # For real arguments conj is a no-op.
        return (arg_objs[0], [])