fix: seperate move and solver RandomGenerator usage (TimefoldAI#2356)

Co-authored-by: Lukáš Petrovický <lukas@timefold.ai>

Author: Christopher-Chianelli

core/src/main/java/ai/timefold/solver/core/impl/exhaustivesearch/DefaultExhaustiveSearchPhaseFactory.java

@@ -162,7 +162,7 @@ protected EntityDescriptor<Solution_> deduceEntityDescriptor(SolutionDescriptor<
             boolean scoreBounderEnabled, boolean isListVariable) {
         var manualEntityMimicRecorder = new ManualEntityMimicRecorder<>(sourceEntitySelector);
         var entityClassName = sourceEntitySelector.getEntityDescriptor().getEntityClass().getName();
-        var mimicSelectorId = ConfigUtils.addRandomSuffix(entityClassName, configPolicy.getRandom());
+        var mimicSelectorId = ConfigUtils.addRandomSuffix(entityClassName, configPolicy.getRandom().factoryUsage());
         configPolicy.addEntityMimicRecorder(mimicSelectorId, manualEntityMimicRecorder);
         var variableDescriptorList = getGenuineVariableDescriptorList(sourceEntitySelector, isListVariable);
         MoveSelectorConfig<?> moveSelectorConfig = phaseConfig.getMoveSelectorConfig();

core/src/main/java/ai/timefold/solver/core/impl/heuristic/HeuristicConfigPolicy.java

@@ -5,7 +5,6 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ThreadFactory;
-import java.util.random.RandomGenerator;
 
 import ai.timefold.solver.core.config.heuristic.selector.entity.EntitySorterManner;
 import ai.timefold.solver.core.config.heuristic.selector.value.ValueSorterManner;
@@ -23,6 +22,7 @@
 import ai.timefold.solver.core.impl.score.definition.ScoreDefinition;
 import ai.timefold.solver.core.impl.score.trend.InitializingScoreTrend;
 import ai.timefold.solver.core.impl.solver.ClassInstanceCache;
+import ai.timefold.solver.core.impl.solver.random.RandomSource;
 import ai.timefold.solver.core.impl.solver.thread.ChildThreadType;
 import ai.timefold.solver.core.impl.solver.thread.DefaultSolverThreadFactory;
 
@@ -42,7 +42,7 @@ public class HeuristicConfigPolicy<Solution_> {
     private final boolean reinitializeVariableFilterEnabled;
     private final boolean unassignedValuesAllowed;
     private final Class<? extends NearbyDistanceMeter<?, ?>> nearbyDistanceMeterClass;
-    private final RandomGenerator random;
+    private final RandomSource random;
 
     private final Map<String, EntityMimicRecorder<Solution_>> entityMimicRecorderMap = new HashMap<>();
     private final Map<String, SubListMimicRecorder<Solution_>> subListMimicRecorderMap = new HashMap<>();
@@ -118,7 +118,7 @@ public Class<? extends NearbyDistanceMeter> getNearbyDistanceMeterClass() {
         return nearbyDistanceMeterClass;
     }
 
-    public RandomGenerator getRandom() {
+    public RandomSource getRandom() {
         return random;
     }
 
@@ -275,7 +275,7 @@ public static class Builder<Solution_> {
         private boolean unassignedValuesAllowed = false;
 
         private Class<? extends NearbyDistanceMeter<?, ?>> nearbyDistanceMeterClass;
-        private RandomGenerator random;
+        private RandomSource random;
 
         public Builder<Solution_> withPreviewFeatureSet(Set<PreviewFeature> previewFeatureSet) {
             this.previewFeatureSet = previewFeatureSet;
@@ -308,7 +308,7 @@ public Builder<Solution_> withThreadFactoryClass(Class<? extends ThreadFactory>
             return this;
         }
 
-        public Builder<Solution_> withRandom(RandomGenerator random) {
+        public Builder<Solution_> withRandom(RandomSource random) {
             this.random = random;
             return this;
         }

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/AbstractSelector.java

@@ -26,7 +26,7 @@ public abstract class AbstractSelector<Solution_> implements Selector<Solution_>
 
     @Override
     public void solvingStarted(SolverScope<Solution_> solverScope) {
-        workingRandom = solverScope.getWorkingRandom();
+        workingRandom = solverScope.getWorkingRandom().moveIteratorUsage();
         phaseLifecycleSupport.fireSolvingStarted(solverScope);
     }
 

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/composite/UnionMoveSelectorFactory.java

@@ -49,7 +49,7 @@ The selector configuration (%s) already includes the Nearby Selection setting, m
                     // Add a new configuration with Nearby Selection enabled
                     moveSelectorConfigList
                             .add(nearbySelectorConfig.enableNearbySelection(configPolicy.getNearbyDistanceMeterClass(),
-                                    configPolicy.getRandom()));
+                                    configPolicy.getRandom().factoryUsage()));
 
                 }
             }

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/RuinRecreateMoveIterator.java

@@ -68,7 +68,7 @@ protected Move<Solution_> createUpcomingSelection() {
             }
         }
         return new SelectorBasedRuinRecreateMove<>(variableDescriptor, constructionHeuristicPhaseBuilder, solverScope,
-                selectedEntityList, affectedValueSet);
+                selectedEntityList, affectedValueSet, workingRandom.nextLong());
     }
 
 }

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/RuinRecreateMoveSelector.java

@@ -55,14 +55,12 @@ public boolean isNeverEnding() {
     public void solvingStarted(SolverScope<Solution_> solverScope) {
         super.solvingStarted(solverScope);
         this.solverScope = solverScope;
-        this.workingRandom = solverScope.getWorkingRandom();
     }
 
     @Override
     public void phaseEnded(AbstractPhaseScope<Solution_> phaseScope) {
         super.phaseEnded(phaseScope);
         this.solverScope = null;
-        this.workingRandom = null;
     }
 
     @Override

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/SelectorBasedRuinRecreateMove.java

@@ -12,6 +12,7 @@
 import ai.timefold.solver.core.impl.move.VariableChangeRecordingScoreDirector;
 import ai.timefold.solver.core.impl.score.director.InnerScoreDirector;
 import ai.timefold.solver.core.impl.score.director.VariableDescriptorAwareScoreDirector;
+import ai.timefold.solver.core.impl.solver.random.DefaultRandomSource;
 import ai.timefold.solver.core.impl.solver.scope.SolverScope;
 import ai.timefold.solver.core.preview.api.move.Move;
 
@@ -26,18 +27,38 @@ public final class SelectorBasedRuinRecreateMove<Solution_> extends AbstractSele
     private final SolverScope<Solution_> solverScope;
     private final List<Object> ruinedEntityList;
     private final SequencedSet<Object> affectedValueSet;
+    private final long randomSeed;
 
     private Object @Nullable [] recordedNewValues;
 
+    /**
+     * Prefer
+     * {@link #SelectorBasedRuinRecreateMove(GenuineVariableDescriptor, RuinRecreateConstructionHeuristicPhaseBuilder, SolverScope, List, SequencedSet, long)}
+     * with explicitly provided random seed.
+     *
+     * @param genuineVariableDescriptor
+     * @param constructionHeuristicPhaseBuilder
+     * @param solverScope
+     * @param ruinedEntityList
+     * @param affectedValueSet
+     */
     public SelectorBasedRuinRecreateMove(GenuineVariableDescriptor<Solution_> genuineVariableDescriptor,
             RuinRecreateConstructionHeuristicPhaseBuilder<Solution_> constructionHeuristicPhaseBuilder,
             SolverScope<Solution_> solverScope, List<Object> ruinedEntityList, SequencedSet<Object> affectedValueSet) {
+        this(genuineVariableDescriptor, constructionHeuristicPhaseBuilder, solverScope, ruinedEntityList, affectedValueSet, 0);
+    }
+
+    public SelectorBasedRuinRecreateMove(GenuineVariableDescriptor<Solution_> genuineVariableDescriptor,
+            RuinRecreateConstructionHeuristicPhaseBuilder<Solution_> constructionHeuristicPhaseBuilder,
+            SolverScope<Solution_> solverScope, List<Object> ruinedEntityList, SequencedSet<Object> affectedValueSet,
+            long randomSeed) {
         this.genuineVariableDescriptor = genuineVariableDescriptor;
         this.ruinedEntityList = ruinedEntityList;
         this.affectedValueSet = affectedValueSet;
         this.constructionHeuristicPhaseBuilder = constructionHeuristicPhaseBuilder;
         this.solverScope = solverScope;
         this.recordedNewValues = null;
+        this.randomSeed = randomSeed;
     }
 
     @Override
@@ -65,6 +86,7 @@ protected void execute(VariableDescriptorAwareScoreDirector<Solution_> scoreDire
         var nestedSolverScope = new SolverScope<Solution_>(solverScope.getClock());
         nestedSolverScope.setSolver(solverScope.getSolver());
         nestedSolverScope.setScoreDirector(innerScoreDirector);
+        nestedSolverScope.setWorkingRandom(DefaultRandomSource.seeded(randomSeed));
         constructionHeuristicPhase.solvingStarted(nestedSolverScope);
         constructionHeuristicPhase.solve(nestedSolverScope);
         constructionHeuristicPhase.solvingEnded(nestedSolverScope);
@@ -90,7 +112,7 @@ public Move<Solution_> rebase(Lookup lookup) {
         var rebasedRuinedEntityList = rebaseList(ruinedEntityList, lookup);
         var rebasedAffectedValueSet = rebaseSet(affectedValueSet, lookup);
         return new SelectorBasedRuinRecreateMove<>(genuineVariableDescriptor, constructionHeuristicPhaseBuilder, solverScope,
-                rebasedRuinedEntityList, rebasedAffectedValueSet);
+                rebasedRuinedEntityList, rebasedAffectedValueSet, randomSeed);
     }
 
     @Override

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/SwapMoveSelectorFactory.java

@@ -51,7 +51,7 @@ protected MoveSelector<Solution_> buildBaseMoveSelector(HeuristicConfigPolicy<So
             if (entitySelectorConfig.getId() == null && entitySelectorConfig.getMimicSelectorRef() == null) {
                 var entityName = Objects.requireNonNull(entityDescriptor.getEntityClass().getSimpleName());
                 // We set the id to make sure the value selector will use the mimic recorder
-                entityRecorderId = ConfigUtils.addRandomSuffix(entityName, configPolicy.getRandom());
+                entityRecorderId = ConfigUtils.addRandomSuffix(entityName, configPolicy.getRandom().factoryUsage());
                 entitySelectorConfig.setId(entityRecorderId);
             } else {
                 entityRecorderId = entitySelectorConfig.getId() != null ? entitySelectorConfig.getId()

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/ListChangeMoveSelectorFactory.java

@@ -83,7 +83,7 @@ protected MoveSelector<Solution_> buildBaseMoveSelector(HeuristicConfigPolicy<So
             if (mimicSelectorConfig.getMimicSelectorRef() == null && mimicSelectorConfig.getId() == null) {
                 var variableName = Objects.requireNonNull(mimicSelectorConfig.getVariableName());
                 // We set the id to make sure the value selector will use the mimic recorder
-                entityValueRangeRecorderId = ConfigUtils.addRandomSuffix(variableName, configPolicy.getRandom());
+                entityValueRangeRecorderId = ConfigUtils.addRandomSuffix(variableName, configPolicy.getRandom().factoryUsage());
                 mimicSelectorConfig.setId(entityValueRangeRecorderId);
             } else {
                 entityValueRangeRecorderId =

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/ListSwapMoveSelectorFactory.java

@@ -50,7 +50,7 @@ protected MoveSelector<Solution_> buildBaseMoveSelector(HeuristicConfigPolicy<So
             if (valueSelectorConfig.getId() == null && valueSelectorConfig.getMimicSelectorRef() == null) {
                 var variableName = Objects.requireNonNull(valueSelectorConfig.getVariableName());
                 // We set the id to make sure the value selector will use the mimic recorder
-                entityValueRangeRecorderId = ConfigUtils.addRandomSuffix(variableName, configPolicy.getRandom());
+                entityValueRangeRecorderId = ConfigUtils.addRandomSuffix(variableName, configPolicy.getRandom().factoryUsage());
                 valueSelectorConfig.setId(entityValueRangeRecorderId);
             } else {
                 entityValueRangeRecorderId = valueSelectorConfig.getId() != null ? valueSelectorConfig.getId()