solve_model.py

# Copyright 2010-2024 Google LLC
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Minimal solver python binary."""

from collections.abc import Sequence

from absl import app
from absl import flags

from ortools.linear_solver.python import model_builder

_INPUT = flags.DEFINE_string("input", "", "Input file to load and solve.")
_PARAMS = flags.DEFINE_string("params", "", "Solver parameters in string format.")
_SOLVER = flags.DEFINE_string("solver", "sat", "Solver type to solve the model with.")


def main(argv: Sequence[str]) -> None:
    """Load a model and solves it."""
    if len(argv) > 1:
        raise app.UsageError("Too many command-line arguments.")

    model = model_builder.ModelBuilder()

    # Load MPS or proto file.
    if _INPUT.value.endswith(".mps"):
        if not model.import_from_mps_file(_INPUT.value):
            print(f"Cannot import MPS file: '{_INPUT.value}'")
            return
    elif not model.import_from_proto_file(_INPUT.value):
        print(f"Cannot import Proto file: '{_INPUT.value}'")
        return

    # Create solver.
    solver = model_builder.ModelSolver(_SOLVER.value)
    if not solver.solver_is_supported():
        print(f"Cannot create solver with name '{_SOLVER.value}'")
        return

    # Set parameters.
    if _PARAMS.value:
        solver.set_solver_specific_parameters(_PARAMS.value)

    # Enable the output of the solver.
    solver.enable_output(True)

    # And solve.
    solver.solve(model)


if __name__ == "__main__":
    app.run(main)