def _presolve(self, *args, **kwds):
"""
Peform presolves.
"""
TempfileManager.push()
self._keepfiles = kwds.pop("keepfiles", False)
self._define_signal_handlers = kwds.pop('use_signal_handling',None)
OptSolver._presolve(self, *args, **kwds)
#
# Verify that the input problems exists
#
for filename in self._problem_files:
if not os.path.exists(filename):
msg = 'Solver failed to locate input problem file: %s'
raise ValueError(msg % filename)
#
# Create command line
#
self._command = self.create_command_line(
self.executable(), self._problem_files)
self._log_file=self._command.log_file
#
# The pre-cleanup is probably unncessary, but also not harmful.
#
if (self._log_file is not None) and \
os.path.exists(self._log_file):
os.remove(self._log_file)
if (self._soln_file is not None) and \
os.path.exists(self._soln_file):
os.remove(self._soln_file)
def _presolve(self, **kwds):
warmstart_flag = kwds.pop('warmstart', False)
self._keepfiles = kwds.pop('keepfiles', False)
self._save_results = kwds.pop('save_results', True)
self._integer_only_warmstarts = kwds.pop('integer_only_warmstarts',
False)
# create a context in the temporary file manager for
# this plugin - is "pop"ed in the _postsolve method.
TempfileManager.push()
self.results = None
model = self._pyomo_model
# this implies we have a custom solution "parser",
# preventing the OptSolver _presolve method from
# creating one
self._results_format = ResultsFormat.soln
# use the base class _presolve to consume the
# important keywords
OptSolver._presolve(self, **kwds)
# ***********************************************************
# The following code is only needed for backwards compatability of load_solutions=False.
# If we ever only want to support the load_vars, load_duals, etc. methods, then this can be deleted.
if self._save_results:
self._smap_id = id(self._symbol_map)
if isinstance(self._pyomo_model, IBlock):
# BIG HACK (see pyomo.core.kernel write function)
if not hasattr(self._pyomo_model, "._symbol_maps"):
setattr(self._pyomo_model, "._symbol_maps", {})
getattr(self._pyomo_model,
"._symbol_maps")[self._smap_id] = self._symbol_map
else:
self._pyomo_model.solutions.add_symbol_map(self._symbol_map)
# ***********************************************************
if warmstart_flag:
if self.warm_start_capable():
self._warm_start()
else:
raise ValueError(
'{0} solver plugin is not capable of warmstart.'.format(
type(self)))
if self._log_file is None:
self._log_file = TempfileManager.create_tempfile(suffix='.log')
