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fix #4677

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This commit is contained in:
Laurent Perron
2025-06-10 16:29:34 +02:00
parent 7c52f28d70
commit 52e4c24a9e
1 changed files with 17 additions and 13 deletions
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30
ortools/sat/scheduling_cuts.cc
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@@ -1102,26 +1102,25 @@ std::string CompletionTimeEvent::DebugString() const {
void CtExhaustiveHelper::Init(
const absl::Span<const CompletionTimeEvent> events, Model* model) {
max_task_index_ = 0;
if (events.empty() || events.size() > 100) return;
BinaryRelationsMaps* binary_relations =
model->GetOrCreate<BinaryRelationsMaps>();
max_task_index_ = 0;
for (const auto& event : events) {
max_task_index_ = std::max(max_task_index_, event.task_index);
}
std::vector<CompletionTimeEvent> sorted_events(events.begin(), events.end());
std::sort(sorted_events.begin(), sorted_events.end(),
[](const CompletionTimeEvent& a, const CompletionTimeEvent& b) {
return a.task_index < b.task_index;
});
max_task_index_ = sorted_events.back().task_index;
predecessors_.reserve(max_task_index_ + 1);
for (const auto& e1 : events) {
CHECK_LE(predecessors_.size(), e1.task_index);
while (predecessors_.size() <= e1.task_index) {
predecessors_.Add({});
}
// Cap the number of precedences to avoid O(n^2) time complexity.
if (predecessors_.num_entries() > 20000) break;
for (const auto& e2 : events) {
if (e2.task_index == e1.task_index) continue;
if (binary_relations->GetLevelZeroPrecedenceStatus(e2.end, e1.start) ==
RelationStatus::IS_TRUE) {
while (predecessors_.size() <= e1.task_index) predecessors_.Add({});
predecessors_.AppendToLastVector(e2.task_index);
}
}
@@ -1138,6 +1137,7 @@ bool CtExhaustiveHelper::PermutationIsCompatibleWithPrecedences(
visited_.assign(max_task_index_ + 1, false);
for (int i = permutation.size() - 1; i >= 0; --i) {
const CompletionTimeEvent& event = events[permutation[i]];
if (event.task_index >= predecessors_.size()) continue;
for (const int predecessor : predecessors_[event.task_index]) {
if (visited_[predecessor]) return false;
}
@@ -1328,9 +1328,11 @@ CompletionTimeExplorationStatus ComputeMinSumOfWeightedEndMins(
helper.task_to_index_[events[i].task_index] = i;
}
helper.valid_permutation_iterator_.Reset(events.size());
const auto& predecessors = helper.predecessors();
for (int i = 0; i < events.size(); ++i) {
const int task_i = events[i].task_index;
for (const int task_j : helper.predecessors()[task_i]) {
if (task_i >= predecessors.size()) continue;
for (const int task_j : predecessors[task_i]) {
const int j = helper.task_to_index_[task_j];
if (j != -1) {
helper.valid_permutation_iterator_.AddArc(j, i);
@@ -1456,6 +1458,7 @@ ABSL_MUST_USE_RESULT bool GenerateShortCompletionTimeCutsWithExactBound(
helper, min_sum_of_ends, min_sum_of_weighted_ends,
cut_use_precedences, exploration_limit);
if (status == CompletionTimeExplorationStatus::NO_VALID_PERMUTATION) {
// TODO(user): We should return false here but there is a bug.
break;
} else if (status == CompletionTimeExplorationStatus::ABORTED) {
break;
@@ -1846,6 +1849,7 @@ CutGenerator CreateCumulativeCompletionTimeCutGenerator(
auto generate_cuts = [integer_trail, sat_solver, model, manager, helper,
demands_helper,
capacity](bool time_is_forward) -> bool {
DCHECK_EQ(sat_solver->CurrentDecisionLevel(), 0);
if (!helper->SynchronizeAndSetTimeDirection(time_is_forward)) {
return false;
}