Source code for pyomo.contrib.preprocessing.plugins.strip_bounds

#  ___________________________________________________________________________
#
#  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.
#  ___________________________________________________________________________

"""Transformation to strip variable bounds from a model."""

from pyomo.common.collections import ComponentMap
from pyomo.common.config import ConfigBlock, ConfigValue, add_docstring_list
from pyomo.core.base.plugin import TransformationFactory
from pyomo.core.base.var import Var
from pyomo.core.base.set_types import Reals
from pyomo.core.plugins.transform.hierarchy import NonIsomorphicTransformation


[docs]@TransformationFactory.register('contrib.strip_var_bounds', doc="Strip bounds from varaibles.") class VariableBoundStripper(NonIsomorphicTransformation): """Strip bounds from variables. Keyword arguments below are specified for the ``apply_to`` and ``create_using`` functions. """ CONFIG = ConfigBlock() CONFIG.declare("strip_domains", ConfigValue( default=True, domain=bool, description="strip the domain for discrete variables as well" )) CONFIG.declare("reversible", ConfigValue( default=False, domain=bool, description="Whether the bound stripping will be temporary. " "If so, store information for reversion." )) __doc__ = add_docstring_list(__doc__, CONFIG) def _apply_to(self, instance, **kwds): config = self.CONFIG(kwds) if config.reversible: if any(hasattr(instance, map_name) for map_name in [ '_tmp_var_bound_strip_lb', '_tmp_var_bound_strip_ub', '_tmp_var_bound_strip_domain']): raise RuntimeError( 'Variable stripping reversion component maps already ' 'exist. Did you already apply a temporary transformation ' 'without a subsequent reversion?') # Component maps to store data for reversion. instance._tmp_var_bound_strip_lb = ComponentMap() instance._tmp_var_bound_strip_ub = ComponentMap() instance._tmp_var_bound_strip_domain = ComponentMap() for var in instance.component_data_objects(ctype=Var): if config.strip_domains and not var.domain == Reals: if config.reversible: instance._tmp_var_bound_strip_domain[var] = var.domain var.domain = Reals if var.has_lb(): if config.reversible: instance._tmp_var_bound_strip_lb[var] = var.lb var.setlb(None) if var.has_ub(): if config.reversible: instance._tmp_var_bound_strip_ub[var] = var.ub var.setub(None)
[docs] def revert(self, instance): """Revert variable bounds and domains changed by the transformation.""" for var in instance.component_data_objects( ctype=Var, descend_into=True): if var in instance._tmp_var_bound_strip_lb: var.setlb(instance._tmp_var_bound_strip_lb[var]) if var in instance._tmp_var_bound_strip_ub: var.setub(instance._tmp_var_bound_strip_ub[var]) if var in instance._tmp_var_bound_strip_domain: var.domain = instance._tmp_var_bound_strip_domain[var] del instance._tmp_var_bound_strip_lb del instance._tmp_var_bound_strip_ub del instance._tmp_var_bound_strip_domain