capacity.proto

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// 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.
 
syntax = "proto3";
 
package operations_research;
 
option java_package = "com.google.ortools.setcover";
option java_multiple_files = true;
 
// Represents a capacity constraint to be used in conjunction with a
// SetCoverProto. This constraint only considers one dimension.
//
// Such a capacity constraint mathematically looks like:
//     min_capacity <= \sum_{e in elements} weight_e * x_e <= max_capacity
// where either `min_capacity` or `max_capacity` can be omitted. `x_e` indicates
// for a given solution `x` whether the element `e` is selected and counts for
// this capacity constraint (`x_e == 1`) or not (`x_e == 0`). The weights are
// given in `capacity_term`, each of them being a reference to an element being
// present in a subset (in set-covering parlance) and its weight.
//
// For instance, this constraint can be used together with a set-covering
// problem where parcels (element) must be covered by trucks (subsets) while
// respecting truck capacities (this object). Each element can be covered by a
// given set of trucks (set-covering problem); if an element is taken within a
// truck, it uses some capacity for this truck (such as weight).
//
// In particular, this representation does not imply that a given element must
// have the same weight in all the capacity constraints of a set-covering
// problem (e.g., the same parcel might have different weights depending on
// which truck is being considered).
message CapacityConstraintProto {
  message CapacityTerm {
    // The subset this weight corresponds to (index of the subset in the
    // `subset` repeated field in `SetCoverProto`).
    int64 subset = 1;
 
    message ElementWeightPair {
      // The element this weight corresponds to (value of `element` in
      // `SetCoverProto.Subset`).
      int64 element = 1;
 
      // The weight of the element.
      int64 weight = 2;
    }
 
    repeated ElementWeightPair element_weights = 2;
  }
 
  // The list of terms in the constraint.
  //
  // The list is supposed to be in canonical form, which means it is sorted
  // first by increasing subset index then increasing element index.
  // No duplicate term is allowed (two terms for the same element in the same
  // subset).
  repeated CapacityTerm capacity_term = 1;
 
  // The minimum amount of resource that must be consumed. At least one of
  // `min_capacity` and `max_capacity` must be present.
  int64 min_capacity = 2;
 
  // The maximum amount of resource that can be consumed. At least one of
  // `min_capacity` and `max_capacity` must be present.
  int64 max_capacity = 3;
}