a7f49a2585
* rename swig files .i in .swig * update constraint_solver and routing * backport math_opt changes * move dynamic loading to ortools/third_party_solvers
111 lines
4.3 KiB
C++
111 lines
4.3 KiB
C++
// Copyright 2010-2025 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef OR_TOOLS_CONSTRAINT_SOLVER_ROUTING_BREAKS_H_
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#define OR_TOOLS_CONSTRAINT_SOLVER_ROUTING_BREAKS_H_
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#include <cstdint>
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#include <utility>
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#include <vector>
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#include "absl/types/span.h"
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#include "ortools/constraint_solver/routing_filter_committables.h"
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namespace operations_research {
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class BreakPropagator {
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public:
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explicit BreakPropagator(int num_nodes);
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// Result of a propagation: kInfeasible means some infeasibility was found,
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// kChanged means that the propagation tightened the bounds of some intervals,
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// kUnchanged means that the propagation did not change anything.
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enum class PropagationResult { kInfeasible, kChanged, kUnchanged };
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// TODO(user): when the OSS version is at C++20, replace this by
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// using enum PropagationResult;
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static constexpr PropagationResult kInfeasible =
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PropagationResult::kInfeasible;
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static constexpr PropagationResult kChanged = PropagationResult::kChanged;
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static constexpr PropagationResult kUnchanged = PropagationResult::kUnchanged;
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// Applies fast propagations, O(log |path|) per break, to the given path.
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PropagationResult FastPropagations(int path,
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DimensionValues& dimension_values,
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const PrePostVisitValues& visits);
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// Propagates interbreak rules on a given path, with a covering reasoning.
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// Each interbreak is a pair (interbreak_limit, min_break_duration).
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PropagationResult PropagateInterbreak(
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int path, DimensionValues& dimension,
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absl::Span<const std::pair<int64_t, int64_t>> interbreaks);
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private:
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using Interval = DimensionValues::Interval;
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using VehicleBreak = DimensionValues::VehicleBreak;
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static bool IncreaseMin(int64_t new_min, Interval* interval,
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PropagationResult* propagation_result) {
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if (interval->min >= new_min) return true;
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if (!interval->IncreaseMin(new_min)) {
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*propagation_result = kInfeasible;
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return false;
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}
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*propagation_result = kChanged;
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return true;
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}
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static bool DecreaseMax(int64_t new_max, Interval* interval,
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PropagationResult* propagation_result) {
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if (interval->max <= new_max) return true;
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if (!interval->DecreaseMax(new_max)) {
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*propagation_result = kInfeasible;
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return false;
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}
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*propagation_result = kChanged;
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return true;
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}
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static bool IntersectWith(Interval source, Interval* target,
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PropagationResult* propagation_result) {
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if (!source.IntersectWith(*target)) {
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*propagation_result = kInfeasible;
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} else if (source != *target) {
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*propagation_result = kChanged;
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}
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*target = source;
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return *propagation_result != kInfeasible;
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}
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// In cases where propagators expect some property of variables to hold,
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// for instance "cumuls[i].min should be weakly increasing in i",
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// it is necessary to delay modification of the variables until after all
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// propagations are done.
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// This struct can be used to store such delayed propagations.
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struct DelayedPropagation {
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int64_t value; // New bound of the variable.
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int index; // Some information on which variable to modify.
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bool is_min; // The bound is a min if this is true, otherwise a max.
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};
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std::vector<DelayedPropagation> delayed_propagations_;
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// Events used in PropagateInterbreak().
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struct UsageEvent {
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int64_t time;
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int index;
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bool is_start;
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bool operator<(const UsageEvent& other) const { return time < other.time; }
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};
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std::vector<UsageEvent> usage_events_;
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// Per-transition reasoning.
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CommittableArray<int64_t> break_duration_on_transition_;
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};
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} // namespace operations_research
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#endif // OR_TOOLS_CONSTRAINT_SOLVER_ROUTING_BREAKS_H_
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