# ____________________________________________________________________________________
#
# Pyomo: Python Optimization Modeling Objects
# Copyright (c) 2008-2026 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.common import Factory
WriterFactory = Factory('problem writer')
[docs]
class AbstractProblemWriter:
"""Base class that can write optimization problems."""
[docs]
def __init__(self, problem_format): # pragma:nocover
self.format = problem_format
def __call__(self, model, filename, solver_capability, **kwds): # pragma:nocover
raise TypeError(
"Method __call__ undefined in writer for format " + str(self.format)
)
#
# Support "with" statements.
#
def __enter__(self):
return self
def __exit__(self, t, v, traceback):
pass
[docs]
class BranchDirection:
"""Allowed values for MIP variable branching directions in the `direction` Suffix of a model."""
default = 0
down = -1
up = 1
ALL = {default, down, up}