# ___________________________________________________________________________
#
# Pyomo: Python Optimization Modeling Objects
# Copyright (c) 2008-2024
# 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)