"""
Copyright 2013 Steven Diamond
This file is part of CVXPY.
CVXPY is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
CVXPY is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with CVXPY. If not, see <http://www.gnu.org/licenses/>.
"""
from .noncvx_variable import NonCvxVariable
import cvxpy.lin_ops.lin_utils as lu
from cvxpy import norm
import numpy as np
class Boolean(NonCvxVariable):
""" A boolean variable. """
# Sets the initial z value to a matrix of 0.5's.
def init_z(self, random):
if random:
self.z.value = np.random.uniform(size=self.shape)
else:
self.z.value = np.zeros(self.shape) + 0.5
# All values set rounded to zero or 1.
def _project(self, matrix):
return np.around(matrix) #> 0
# Constrain all entries to be the value in the matrix.
def _restrict(self, matrix):
return [self == matrix]
def _neighbors(self, matrix):
neighbors_list = []
for i in range(self.shape[0]):
for j in range(self.shape[1]):
new_mat = matrix.copy()
new_mat[i,j] = 1 - new_mat[i,j]
neighbors_list += [new_mat]
return neighbors_list
def relax(self):
"""The convex relaxation.
"""
constr = super(Boolean, self).relax()
return constr + [0 <= self, self <= 1]
