[CP-SAT] more bug fixing

ortools/sat/BUILD.bazel

@@ -3445,6 +3445,7 @@ cc_library(
         "//ortools/base:stl_util",
         "//ortools/graph:connected_components",
         "//ortools/util:adaptative_parameter_value",
+        "//ortools/util:bitset",
         "//ortools/util:integer_pq",
         "//ortools/util:saturated_arithmetic",
         "//ortools/util:sorted_interval_list",

ortools/sat/all_different.cc

@@ -443,8 +443,7 @@ bool AllDifferentConstraint::Propagate() {
 }
 
 AllDifferentBoundsPropagator::AllDifferentBoundsPropagator(
-    const std::vector<AffineExpression>& expressions,
-    IntegerTrail* integer_trail)
+    absl::Span<const AffineExpression> expressions, IntegerTrail* integer_trail)
     : integer_trail_(integer_trail) {
   CHECK(!expressions.empty());
 

ortools/sat/all_different.h

@@ -150,7 +150,7 @@ class AllDifferentConstraint : PropagatorInterface {
 // https://cs.uwaterloo.ca/~vanbeek/Publications/ijcai03_TR.pdf
 class AllDifferentBoundsPropagator : public PropagatorInterface {
  public:
-  AllDifferentBoundsPropagator(const std::vector<AffineExpression>& expressions,
+  AllDifferentBoundsPropagator(absl::Span<const AffineExpression> expressions,
                                IntegerTrail* integer_trail);
 
   // This type is neither copyable nor movable.

ortools/sat/cp_model_lns.cc

@@ -58,6 +58,7 @@
 #include "ortools/sat/synchronization.h"
 #include "ortools/sat/util.h"
 #include "ortools/util/adaptative_parameter_value.h"
+#include "ortools/util/bitset.h"
 #include "ortools/util/integer_pq.h"
 #include "ortools/util/saturated_arithmetic.h"
 #include "ortools/util/sorted_interval_list.h"
@@ -949,7 +950,8 @@ NeighborhoodGeneratorHelper::GetSchedulingPrecedences(
   return result;
 }
 
-std::vector<std::vector<int>> NeighborhoodGeneratorHelper::GetRoutingPaths(
+std::vector<std::vector<int>>
+NeighborhoodGeneratorHelper::GetRoutingPathLiterals(
     const CpSolverResponse& initial_solution) const {
   struct HeadAndArcLiteral {
     int head;
@@ -2596,7 +2598,7 @@ Neighborhood RoutingRandomNeighborhoodGenerator::Generate(
     const CpSolverResponse& initial_solution, SolveData& data,
     absl::BitGenRef random) {
   const std::vector<std::vector<int>> all_paths =
-      helper_.GetRoutingPaths(initial_solution);
+      helper_.GetRoutingPathLiterals(initial_solution);
 
   // Collect all unique variables.
   absl::flat_hash_set<int> all_path_variables;
@@ -2617,7 +2619,7 @@ Neighborhood RoutingPathNeighborhoodGenerator::Generate(
     const CpSolverResponse& initial_solution, SolveData& data,
     absl::BitGenRef random) {
   std::vector<std::vector<int>> all_paths =
-      helper_.GetRoutingPaths(initial_solution);
+      helper_.GetRoutingPathLiterals(initial_solution);
 
   // Collect all unique variables.
   absl::flat_hash_set<int> all_path_variables;
@@ -2663,7 +2665,7 @@ Neighborhood RoutingFullPathNeighborhoodGenerator::Generate(
     const CpSolverResponse& initial_solution, SolveData& data,
     absl::BitGenRef random) {
   std::vector<std::vector<int>> all_paths =
-      helper_.GetRoutingPaths(initial_solution);
+      helper_.GetRoutingPathLiterals(initial_solution);
   // Remove a corner case where all paths are empty.
   if (all_paths.empty()) {
     return helper_.NoNeighborhood();

ortools/sat/cp_model_lns.h

@@ -15,6 +15,7 @@
 #define OR_TOOLS_SAT_CP_MODEL_LNS_H_
 
 #include <cmath>
+#include <cstddef>
 #include <cstdint>
 #include <functional>
 #include <memory>
@@ -39,6 +40,7 @@
 #include "ortools/sat/synchronization.h"
 #include "ortools/sat/util.h"
 #include "ortools/util/adaptative_parameter_value.h"
+#include "ortools/util/bitset.h"
 
 namespace operations_research {
 namespace sat {
@@ -250,7 +252,7 @@ class NeighborhoodGeneratorHelper : public SubSolver {
   // self-looping arcs. Path are sorted, starting from the arc with the lowest
   // tail index, and going in sequence up to the last arc before the circuit is
   // closed. Each entry correspond to the arc literal on the circuit.
-  std::vector<std::vector<int>> GetRoutingPaths(
+  std::vector<std::vector<int>> GetRoutingPathLiterals(
       const CpSolverResponse& initial_solution) const;
 
   // Returns all precedences extracted from the scheduling constraint and the

ortools/sat/cp_model_solver.cc

@@ -818,6 +818,10 @@ void RestrictObjectiveUsingHint(CpModelProto* model_proto) {
 bool SolutionHintIsCompleteAndFeasible(
     const CpModelProto& model_proto, SolverLogger* logger = nullptr,
     SharedResponseManager* manager = nullptr) {
+  if (!model_proto.has_solution_hint() && model_proto.variables_size() > 0) {
+    return false;
+  }
+
   int num_active_variables = 0;
   int num_hinted_variables = 0;
   for (int var = 0; var < model_proto.variables_size(); ++var) {

ortools/sat/linear_relaxation.cc

@@ -1059,7 +1059,8 @@ void AppendNoOverlap2dRelaxation(const ConstraintProto& ct, Model* model,
       const IntegerValue area_min =
           integer_trail->LevelZeroLowerBound(x_sizes[i]) *
           integer_trail->LevelZeroLowerBound(y_sizes[i]);
-      if (area_min != 0) {
+      if (area_min > 0) {
+        // Note that intervals that must be absent can have negative sizes.
         // Not including the term if we don't have a view is ok.
         (void)lc.AddLiteralTerm(presence_literal, area_min);
       }