Source code for picos.constraints.con_soc

# coding: utf-8

# ------------------------------------------------------------------------------
# Copyright (C) 2018-2019 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.
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"""Second order conce constraints."""

from collections import namedtuple

from .. import glyphs
from ..apidoc import api_end, api_start
from .constraint import Constraint

_API_START = api_start(globals())
# -------------------------------


[docs]class SOCConstraint(Constraint): """Second order (:math:`2`-norm, Lorentz) cone membership constraint."""
[docs] def __init__(self, normedExpression, upperBound, customString=None): """Construct a :class:`SOCConstraint`. :param ~picos.expressions.AffineExpression normedExpression: Expression under the norm. :param ~picos.expressions.AffineExpression upperBound: Upper bound on the normed expression. :param str customString: Optional string description. """ from ..expressions import AffineExpression assert isinstance(normedExpression, AffineExpression) assert isinstance(upperBound, AffineExpression) assert len(upperBound) == 1 # NOTE: len(normedExpression) == 1 is allowed even though this should # rather be represented as an AbsoluteValueConstraint. self.ne = normedExpression self.ub = upperBound super(SOCConstraint, self).__init__( self._get_type_term(), customString, printSize=True)
def _get_type_term(self): return "SOC" Subtype = namedtuple("Subtype", ("argdim",)) def _subtype(self): return self.Subtype(len(self.ne)) @classmethod def _cost(cls, subtype): return subtype.argdim + 1 def _expression_names(self): yield "ne" yield "ub" def _str(self): return glyphs.le(glyphs.norm(self.ne.string), self.ub.string) def _get_size(self): return (len(self.ne) + 1, 1) def _get_slack(self): return self.ub.value - abs(self.ne).value
# -------------------------------------- __all__ = api_end(_API_START, globals())