Source code for pyomo.core.kernel.sos

#  ___________________________________________________________________________
#
#  Pyomo: Python Optimization Modeling Objects
#  Copyright 2017 National Technology and Engineering Solutions of Sandia, LLC
#  Under the terms of Contract DE-NA0003525 with National Technology and
#  Engineering Solutions of Sandia, LLC, the U.S. Government retains certain
#  rights in this software.
#  This software is distributed under the 3-clause BSD License.
#  ___________________________________________________________________________

from pyomo.core.expr.numvalue import is_numeric_data
from pyomo.core.kernel.base import \
    (ICategorizedObject,
     _abstract_readwrite_property)
from pyomo.core.kernel.container_utils import \
    define_simple_containers


class ISOS(ICategorizedObject):
    """
    The interface for Special Ordered Sets.
    """
    __slots__ = ()

    #
    # Implementations can choose to define these
    # properties as using __slots__, __dict__, or
    # by overriding the @property method
    #

    variables = _abstract_readwrite_property(
        doc="The sos variables")
    weights = _abstract_readwrite_property(
        doc="The sos variables")
    level = _abstract_readwrite_property(
        doc="The sos level (e.g., 1,2,...)")

    #
    # Interface
    #

    def items(self):
        """Iterator over the sos variables and weights as tuples"""
        return zip(self.variables, self.weights)

    def __contains__(self, v):
        """Check if the sos contains the variable v"""
        for x in self.variables:
            if id(x) == id(v):
                return True

    def __len__(self):
        """The number of members in the set"""
        return len(self.variables)

[docs]class sos(ISOS): """A Special Ordered Set of type n.""" _ctype = ISOS __slots__ = ("_parent", "_storage_key", "_active", "_variables", "_weights", "_level", "__weakref__") def __init__(self, variables, weights=None, level=1): self._parent = None self._storage_key = None self._active = True self._variables = tuple(variables) self._weights = None self._level = level if weights is None: self._weights = tuple(range(1,len(self._variables)+1)) else: self._weights = tuple(weights) for w in self._weights: if not is_numeric_data(w): raise ValueError( "Weights for Special Ordered Sets must be " "expressions restricted to numeric data") assert len(self._variables) == len(self._weights) assert self._level >= 1 # # Define the ISOS abstract methods # @property def variables(self): return self._variables @property def weights(self): return self._weights @property def level(self): return self._level
[docs]def sos1(variables, weights=None): """A Special Ordered Set of type 1. This is an alias for sos(..., level=1)""" return sos(variables, weights=weights, level=1)
[docs]def sos2(variables, weights=None): """A Special Ordered Set of type 2. This is an alias for sos(..., level=2). """ return sos(variables, weights=weights, level=2)
# inserts class definitions for simple _tuple, _list, and # _dict containers into this module define_simple_containers(globals(), "sos", ISOS)