Source code for pyomo.core.kernel.objective

#  ___________________________________________________________________________
#  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 as_numeric
from pyomo.core.kernel.base import _abstract_readwrite_property
from pyomo.core.kernel.container_utils import define_simple_containers
from pyomo.core.kernel.expression import IExpression

# Constants used to define the optimization sense

class IObjective(IExpression):
    The interface for optimization objectives.
    __slots__ = ()

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

    sense = _abstract_readwrite_property(
        doc=("The optimization direction for the "
             "objective (minimize or maximize)"))

    # Interface

    def is_minimizing(self):
        return self.sense == minimize

[docs]class objective(IObjective): """An optimization objective.""" _ctype = IObjective __slots__ = ("_parent", "_storage_key", "_active", "_expr", "_sense", "__weakref__") def __init__(self, expr=None, sense=minimize): self._parent = None self._storage_key = None self._active = True self._expr = None self._sense = None # call the setters self.sense = sense self.expr = expr # # Define the IExpression abstract methods # @property def expr(self): return self._expr @expr.setter def expr(self, expr): self._expr = as_numeric(expr) if (expr is not None) else None # # Define the IObjective abstract methods # @property def sense(self): return self._sense @sense.setter def sense(self, sense): """Set the sense (direction) of this objective.""" if (sense == minimize) or \ (sense == maximize): self._sense = sense else: raise ValueError( "Objective sense must be set to one of: " "[minimize (%s), maximize (%s)]. Invalid " "value: %s'" % (minimize, maximize, sense))
# inserts class definitions for simple _tuple, _list, and # _dict containers into this module define_simple_containers(globals(), "objective", IObjective)