ortools-clone/ortools/sat/samples/optional_interval_sample_sat.py

#!/usr/bin/env python3
# Copyright 2010-2025 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.

# [START program]
"""Code sample to demonstrates how to build an optional interval."""

from ortools.sat.python import cp_model


def optional_interval_sample_sat():
    """Showcases how to build optional interval variables."""
    model = cp_model.CpModel()
    horizon = 100

    # An interval can be created from three affine expressions.
    start_var = model.new_int_var(0, horizon, "start")
    duration = 10  # Python cp/sat code accept integer variables or constants.
    end_var = model.new_int_var(0, horizon, "end")
    presence_var = model.new_bool_var("presence")
    interval_var = model.new_optional_interval_var(
        start_var, duration, end_var + 2, presence_var, "interval"
    )

    print(f"interval = {repr(interval_var)}")

    # If the size is fixed, a simpler version uses the start expression and the
    # size.
    fixed_size_interval_var = model.new_optional_fixed_size_interval_var(
        start_var, 10, presence_var, "fixed_size_interval_var"
    )
    print(f"fixed_size_interval_var = {repr(fixed_size_interval_var)}")

    # A fixed interval can be created using the same API.
    fixed_interval = model.new_optional_fixed_size_interval_var(
        5, 10, presence_var, "fixed_interval"
    )
    print(f"fixed_interval = {repr(fixed_interval)}")


optional_interval_sample_sat()
# [END program]