# ------------------------------------------------------------------------------
# Copyright (C) 2020 Maximilian Stahlberg
#
# This file is part of PICOS.
#
# PICOS 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.
#
# PICOS 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
# this program. If not, see <http://www.gnu.org/licenses/>.
# ------------------------------------------------------------------------------
"""Implements the nonnegative orthant cone."""
import operator
from collections import namedtuple
from .. import glyphs
from ..apidoc import api_end, api_start
from ..constraints import AffineConstraint
from ..constraints.uncertain import ConicallyUncertainAffineConstraint
from .cone import Cone
from .exp_affine import AffineExpression
from .uncertain.pert_conic import ConicPerturbationSet
from .uncertain.uexp_affine import UncertainAffineExpression
_API_START = api_start(globals())
# -------------------------------
[docs]class NonnegativeOrthant(Cone):
"""The nonnegative orthant."""
[docs] def __init__(self, dim=None):
"""Construct a :class:`NonnegativeOrthant`."""
Cone.__init__(self, dim, "Nonnegative Orthant",
glyphs.set(glyphs.ge("x", glyphs.scalar(0))))
def _get_mutables(self):
return frozenset()
def _replace_mutables(self):
return self
Subtype = namedtuple("Subtype", ("dim",))
def _get_subtype(self):
return self.Subtype(self.dim)
@classmethod
def _predict(cls, subtype, relation, other):
assert isinstance(subtype, cls.Subtype)
if relation == operator.__rshift__:
if issubclass(other.clstype, AffineExpression) \
and not subtype.dim or subtype.dim == other.subtype.dim:
return AffineConstraint.make_type(
dim=other.subtype.dim, eq=False)
elif issubclass(other.clstype, UncertainAffineExpression) \
and not subtype.dim or subtype.dim == other.subtype.dim:
universe = other.subtype.universe_type
if issubclass(universe.clstype, ConicPerturbationSet):
return ConicallyUncertainAffineConstraint.make_type(
dim=other.subtype.dim,
universe_subtype=universe.subtype)
return Cone._predict_base(cls, subtype, relation, other)
def _rshift_implementation(self, element):
if isinstance(element, AffineExpression):
self._check_dimension(element)
return element >= 0
elif isinstance(element, UncertainAffineExpression):
self._check_dimension(element)
if isinstance(element.universe, ConicPerturbationSet):
return ConicallyUncertainAffineConstraint(-element)
# Handle scenario uncertainty for all cones.
return Cone._rshift_base(self, element)
@property
def dual_cone(self):
"""Implement :attr:`.cone.Cone.dual_cone`."""
return self
# --------------------------------------
__all__ = api_end(_API_START, globals())