chore: improve mixed models

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/NearbyAutoConfigurationEnabled.java

@@ -11,6 +11,11 @@
  */
 public interface NearbyAutoConfigurationEnabled<Config_ extends MoveSelectorConfig<Config_>> {
 
+    /**
+     * @return true if it can enable the nearby setting for the given move configuration; otherwise, it returns false.
+     */
+    boolean canEnableNearbyInMixedModels();
+
     /**
      * @return new instance with the Nearby Selection settings properly configured
      */

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/composite/UnionMoveSelectorConfig.java

@@ -206,6 +206,11 @@ public boolean hasNearbySelectionConfig() {
                 && moveSelectorConfigList.stream().anyMatch(MoveSelectorConfig::hasNearbySelectionConfig);
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return false;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "(" + moveSelectorConfigList + ")";

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/generic/ChangeMoveSelectorConfig.java

@@ -104,6 +104,11 @@ public boolean hasNearbySelectionConfig() {
                 || (valueSelectorConfig != null && valueSelectorConfig.hasNearbySelectionConfig());
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return false;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "(" + entitySelectorConfig + ", " + valueSelectorConfig + ")";

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/generic/SwapMoveSelectorConfig.java

@@ -127,6 +127,11 @@ public boolean hasNearbySelectionConfig() {
                 || (secondaryEntitySelectorConfig != null && secondaryEntitySelectorConfig.hasNearbySelectionConfig());
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return false;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "(" + entitySelectorConfig

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/generic/chained/TailChainSwapMoveSelectorConfig.java

@@ -108,6 +108,11 @@ public boolean hasNearbySelectionConfig() {
                 || (valueSelectorConfig != null && valueSelectorConfig.hasNearbySelectionConfig());
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return false;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "(" + entitySelectorConfig + ", " + valueSelectorConfig + ")";

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/generic/list/ListChangeMoveSelectorConfig.java

@@ -106,6 +106,11 @@ public boolean hasNearbySelectionConfig() {
                 || (destinationSelectorConfig != null && destinationSelectorConfig.hasNearbySelectionConfig());
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return true;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "(" + valueSelectorConfig + ", " + destinationSelectorConfig + ")";

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/generic/list/ListSwapMoveSelectorConfig.java

@@ -104,6 +104,11 @@ public boolean hasNearbySelectionConfig() {
                 || (secondaryValueSelectorConfig != null && secondaryValueSelectorConfig.hasNearbySelectionConfig());
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return true;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "(" + valueSelectorConfig

core/src/main/java/ai/timefold/solver/core/config/heuristic/selector/move/generic/list/kopt/KOptListMoveSelectorConfig.java

@@ -138,6 +138,11 @@ public boolean hasNearbySelectionConfig() {
                 || (valueSelectorConfig != null && valueSelectorConfig.hasNearbySelectionConfig());
     }
 
+    @Override
+    public boolean canEnableNearbyInMixedModels() {
+        return true;
+    }
+
     @Override
     public String toString() {
         return getClass().getSimpleName() + "()";

core/src/main/java/ai/timefold/solver/core/impl/domain/solution/descriptor/SolutionDescriptor.java

@@ -166,10 +166,6 @@ public static <Solution_> SolutionDescriptor<Solution_> buildSolutionDescriptor(
             solutionDescriptor.constraintWeightSupplier.initialize(solutionDescriptor,
                     descriptorPolicy.getMemberAccessorFactory(), descriptorPolicy.getDomainAccessType());
         }
-        // Temporally disabling the mixed model
-        if (solutionDescriptor.hasBothBasicAndListVariables()) {
-            throw new IllegalStateException("Combining list variable and basic variables is currently not supported.");
-        }
         return solutionDescriptor;
     }
 

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

@@ -161,6 +161,12 @@ public HeuristicConfigPolicy<Solution_> createPhaseConfigPolicy() {
         return cloneBuilder().build();
     }
 
+    public HeuristicConfigPolicy<Solution_> copyConfigPolicyWithoutNearbySetting() {
+        return cloneBuilder()
+                .withNearbyDistanceMeterClass(null)
+                .build();
+    }
+
     public HeuristicConfigPolicy<Solution_> createChildThreadConfigPolicy(ChildThreadType childThreadType) {
         return cloneBuilder()
                 .withLogIndentation(logIndentation + "        ")

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

@@ -113,8 +113,16 @@ private SubListSelector<Solution_> applyNearbySelection(HeuristicConfigPolicy<So
     private EntityIndependentValueSelector<Solution_> buildEntityIndependentValueSelector(
             HeuristicConfigPolicy<Solution_> configPolicy, EntityDescriptor<Solution_> entityDescriptor,
             SelectionCacheType minimumCacheType, SelectionOrder inheritedSelectionOrder) {
-        ValueSelectorConfig valueSelectorConfig =
-                Objects.requireNonNullElseGet(config.getValueSelectorConfig(), ValueSelectorConfig::new);
+        ValueSelectorConfig valueSelectorConfig = config != null ? config.getValueSelectorConfig() : null;
+        if (valueSelectorConfig == null) {
+            valueSelectorConfig = new ValueSelectorConfig();
+        }
+        // Mixed models require that the variable name be set
+        if (configPolicy.getSolutionDescriptor().hasBothBasicAndListVariables()
+                && valueSelectorConfig.getVariableName() == null) {
+            var variableName = entityDescriptor.getGenuineListVariableDescriptor().getVariableName();
+            valueSelectorConfig.setVariableName(variableName);
+        }
         ValueSelector<Solution_> valueSelector = ValueSelectorFactory
                 .<Solution_> create(valueSelectorConfig)
                 .buildValueSelector(configPolicy, entityDescriptor, minimumCacheType, inheritedSelectionOrder);

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

@@ -26,6 +26,7 @@ protected MoveSelector<Solution_> buildBaseMoveSelector(HeuristicConfigPolicy<So
             SelectionCacheType minimumCacheType, boolean randomSelection) {
         var moveSelectorConfigList = new LinkedList<>(config.getMoveSelectorList());
         if (configPolicy.getNearbyDistanceMeterClass() != null) {
+            var isMixedModel = configPolicy.getSolutionDescriptor().hasBothBasicAndListVariables();
             for (var selectorConfig : config.getMoveSelectorList()) {
                 if (selectorConfig instanceof NearbyAutoConfigurationEnabled nearbySelectorConfig) {
                     if (selectorConfig.hasNearbySelectionConfig()) {
@@ -38,7 +39,12 @@ The selector configuration (%s) already includes the Nearby Selection setting, m
                     // We delay the autoconfiguration to the deepest UnionMoveSelectorConfig node in the tree
                     // to avoid duplicating configuration
                     // when there are nested unionMoveSelector configurations
-                    if (selectorConfig instanceof UnionMoveSelectorConfig) {
+                    var isUnionMoveSelectorConfig = selectorConfig instanceof UnionMoveSelectorConfig;
+                    // When using a mixed model, we do not enable nearby for basic variables,
+                    // as it applies only to list or chained variables.
+                    // Chained variables are forbidden in mixed models.
+                    var isNearbyDisabled = isMixedModel && !nearbySelectorConfig.canEnableNearbyInMixedModels();
+                    if (isUnionMoveSelectorConfig || isNearbyDisabled) {
                         continue;
                     }
                     // Add a new configuration with Nearby Selection enabled

core/src/main/java/ai/timefold/solver/core/impl/phase/PhaseFactory.java

@@ -4,6 +4,7 @@
 import java.util.List;
 
 import ai.timefold.solver.core.config.constructionheuristic.ConstructionHeuristicPhaseConfig;
+import ai.timefold.solver.core.config.constructionheuristic.placer.QueuedEntityPlacerConfig;
 import ai.timefold.solver.core.config.exhaustivesearch.ExhaustiveSearchPhaseConfig;
 import ai.timefold.solver.core.config.localsearch.LocalSearchPhaseConfig;
 import ai.timefold.solver.core.config.partitionedsearch.PartitionedSearchPhaseConfig;
@@ -56,15 +57,28 @@ static <Solution_> List<Phase<Solution_>> buildPhases(List<PhaseConfig> phaseCon
                             + "without a configured termination (" + previousPhaseConfig + ").");
                 }
             }
+            var isConstructionPhase = ConstructionHeuristicPhaseConfig.class.isAssignableFrom(phaseConfig.getClass());
+            // We currently do not support nearby functionality for CH.
+            // Additionally, mixed models must not include any nearby settings for basic variables,
+            // as this may cause failures in certain cases,
+            // such as when defining multiple variables with a Cartesian product.
+            var entityPlacerConfig =
+                    isConstructionPhase ? ((ConstructionHeuristicPhaseConfig) phaseConfig).getEntityPlacerConfig() : null;
+            var disableNearbySetting =
+                    configPolicy.getNearbyDistanceMeterClass() != null && entityPlacerConfig != null
+                            && QueuedEntityPlacerConfig.class.isAssignableFrom(entityPlacerConfig.getClass())
+                            && configPolicy.getSolutionDescriptor().hasBothBasicAndListVariables();
+            var updatedConfigPolicy =
+                    disableNearbySetting ? configPolicy.copyConfigPolicyWithoutNearbySetting() : configPolicy;
             // The initialization phase can only be applied to construction heuristics or custom phases
-            var isConstructionOrCustomPhase = ConstructionHeuristicPhaseConfig.class.isAssignableFrom(phaseConfig.getClass())
-                    || CustomPhaseConfig.class.isAssignableFrom(phaseConfig.getClass());
+            var isConstructionOrCustomPhase =
+                    isConstructionPhase || CustomPhaseConfig.class.isAssignableFrom(phaseConfig.getClass());
             // The next phase must be a local search
             var isNextPhaseLocalSearch = phaseIndex + 1 < phaseConfigList.size()
                     && LocalSearchPhaseConfig.class.isAssignableFrom(phaseConfigList.get(phaseIndex + 1).getClass());
             PhaseFactory<Solution_> phaseFactory = PhaseFactory.create(phaseConfig);
             var phase = phaseFactory.buildPhase(phaseIndex,
-                    !isPhaseSelected && isConstructionOrCustomPhase && isNextPhaseLocalSearch, configPolicy,
+                    !isPhaseSelected && isConstructionOrCustomPhase && isNextPhaseLocalSearch, updatedConfigPolicy,
                     bestSolutionRecaller, termination);
             // Ensure only one initialization phase is set
             if (!isPhaseSelected && isConstructionOrCustomPhase && isNextPhaseLocalSearch) {

core/src/test/java/ai/timefold/solver/core/impl/constructionheuristic/DefaultConstructionHeuristicPhaseTest.java

@@ -47,7 +47,6 @@
 import ai.timefold.solver.core.testutil.AbstractMeterTest;
 import ai.timefold.solver.core.testutil.PlannerTestUtils;
 
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import io.micrometer.core.instrument.Metrics;
@@ -349,7 +348,6 @@ void constructionHeuristicAllocateToValueFromQueue() {
                 .filter(e -> e.getValue() == null)).isEmpty();
     }
 
-    @Disabled("The mixed model is currently unavailable for general use")
     @Test
     void failMixedModelDefaultConfiguration() {
         var solverConfig = PlannerTestUtils

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/composite/UnionMoveSelectorTest.java

@@ -2,6 +2,7 @@
 
 import static ai.timefold.solver.core.testutil.PlannerAssert.assertAllCodesOfMoveSelector;
 import static ai.timefold.solver.core.testutil.PlannerAssert.verifyPhaseLifecycle;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -11,6 +12,7 @@
 import java.util.Map;
 import java.util.Random;
 
+import ai.timefold.solver.core.config.heuristic.selector.move.composite.UnionMoveSelectorConfig;
 import ai.timefold.solver.core.impl.heuristic.move.DummyMove;
 import ai.timefold.solver.core.impl.heuristic.selector.SelectorTestUtils;
 import ai.timefold.solver.core.impl.heuristic.selector.move.MoveSelector;
@@ -211,4 +213,9 @@ void emptyBiasedRandomSelection() {
         verifyPhaseLifecycle(childMoveSelectorList.get(1), 1, 1, 1);
     }
 
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new UnionMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isFalse();
+    }
 }

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/ChangeMoveTest.java

@@ -9,6 +9,7 @@
 
 import ai.timefold.solver.core.api.score.buildin.simple.SimpleScore;
 import ai.timefold.solver.core.api.score.director.ScoreDirector;
+import ai.timefold.solver.core.config.heuristic.selector.move.generic.ChangeMoveSelectorConfig;
 import ai.timefold.solver.core.impl.score.director.easy.EasyScoreDirectorFactory;
 import ai.timefold.solver.core.testdomain.TestdataEntity;
 import ai.timefold.solver.core.testdomain.TestdataSolution;
@@ -168,4 +169,9 @@ void toStringTestMultiVar() {
         assertThat(new ChangeMove<>(variableDescriptor, c, v3)).hasToString("c {v4 -> v3}");
     }
 
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new ChangeMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isFalse();
+    }
 }

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/SwapMoveTest.java

@@ -10,6 +10,7 @@
 
 import ai.timefold.solver.core.api.score.buildin.simple.SimpleScore;
 import ai.timefold.solver.core.api.score.director.ScoreDirector;
+import ai.timefold.solver.core.config.heuristic.selector.move.generic.SwapMoveSelectorConfig;
 import ai.timefold.solver.core.impl.score.director.easy.EasyScoreDirectorFactory;
 import ai.timefold.solver.core.testdomain.TestdataEntity;
 import ai.timefold.solver.core.testdomain.TestdataSolution;
@@ -259,4 +260,9 @@ void toStringTestMultiVar() {
         assertThat(new SwapMove<>(variableDescriptorList, c, b)).hasToString("c {v2, v4, w2} <-> b {v1, v3, w1}");
     }
 
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new SwapMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isFalse();
+    }
 }

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/chained/TailChainSwapMoveTest.java

@@ -8,6 +8,7 @@
 
 import ai.timefold.solver.core.api.score.buildin.simple.SimpleScore;
 import ai.timefold.solver.core.api.score.director.ScoreDirector;
+import ai.timefold.solver.core.config.heuristic.selector.move.generic.chained.TailChainSwapMoveSelectorConfig;
 import ai.timefold.solver.core.impl.domain.solution.descriptor.SolutionDescriptor;
 import ai.timefold.solver.core.impl.domain.variable.anchor.AnchorVariableDemand;
 import ai.timefold.solver.core.impl.domain.variable.anchor.AnchorVariableSupply;
@@ -292,4 +293,10 @@ void extractPlanningEntitiesWithRightEntityNull() {
         move.doMoveOnGenuineVariables(innerScoreDirector);
         assertThat(move.getPlanningEntities()).doesNotContainNull();
     }
+
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new TailChainSwapMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isFalse();
+    }
 }

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/ListChangeMoveTest.java

@@ -12,6 +12,7 @@
 import java.util.stream.Stream;
 
 import ai.timefold.solver.core.api.score.director.ScoreDirector;
+import ai.timefold.solver.core.config.heuristic.selector.move.generic.list.ListChangeMoveSelectorConfig;
 import ai.timefold.solver.core.impl.domain.variable.descriptor.ListVariableDescriptor;
 import ai.timefold.solver.core.impl.score.director.InnerScoreDirector;
 import ai.timefold.solver.core.testdomain.TestdataObject;
@@ -188,4 +189,10 @@ void toStringTest() {
         assertThat(new ListChangeMove<>(variableDescriptor, e1, 1, e1, 0)).hasToString("2 {e1[1] -> e1[0]}");
         assertThat(new ListChangeMove<>(variableDescriptor, e1, 0, e2, 1)).hasToString("1 {e1[0] -> e2[1]}");
     }
+
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new ListChangeMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isTrue();
+    }
 }

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/ListSwapMoveTest.java

@@ -7,6 +7,7 @@
 import static org.mockito.Mockito.verify;
 
 import ai.timefold.solver.core.api.score.director.ScoreDirector;
+import ai.timefold.solver.core.config.heuristic.selector.move.generic.list.ListSwapMoveSelectorConfig;
 import ai.timefold.solver.core.impl.domain.variable.descriptor.ListVariableDescriptor;
 import ai.timefold.solver.core.impl.move.director.MoveDirector;
 import ai.timefold.solver.core.impl.score.director.InnerScoreDirector;
@@ -137,4 +138,10 @@ void toStringTest() {
         assertThat(new ListSwapMove<>(variableDescriptor, e1, 0, e1, 1)).hasToString("1 {e1[0]} <-> 2 {e1[1]}");
         assertThat(new ListSwapMove<>(variableDescriptor, e1, 1, e2, 0)).hasToString("2 {e1[1]} <-> 3 {e2[0]}");
     }
+
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new ListSwapMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isTrue();
+    }
 }

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/SubListChangeMoveSelectorFactoryTest.java

@@ -20,7 +20,6 @@
 import ai.timefold.solver.core.testdomain.list.TestdataListSolution;
 import ai.timefold.solver.core.testdomain.mixed.multientity.TestdataMixedMultiEntitySolution;
 
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
@@ -44,7 +43,6 @@ void buildMoveSelector() {
         assertThat(selector.isSelectReversingMoveToo()).isTrue();
     }
 
-    @Disabled("The mixed model is currently unavailable for general use")
     @Test
     void buildMoveSelectorMultiEntity() {
         var config = new SubListChangeMoveSelectorConfig();

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/SubListSwapMoveSelectorFactoryTest.java

@@ -16,7 +16,6 @@
 import ai.timefold.solver.core.testdomain.list.TestdataListSolution;
 import ai.timefold.solver.core.testdomain.mixed.multientity.TestdataMixedMultiEntitySolution;
 
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
@@ -41,7 +40,6 @@ void buildBaseMoveSelector() {
         assertThat(selector.isSelectReversingMoveToo()).isTrue();
     }
 
-    @Disabled("The mixed model is currently unavailable for general use")
     @Test
     void buildMoveSelectorMultiEntity() {
         var config = new SubListSwapMoveSelectorConfig();

core/src/test/java/ai/timefold/solver/core/impl/heuristic/selector/move/generic/list/kopt/KOptListMoveTest.java

@@ -11,6 +11,7 @@
 import java.util.List;
 import java.util.function.Function;
 
+import ai.timefold.solver.core.config.heuristic.selector.move.generic.list.kopt.KOptListMoveSelectorConfig;
 import ai.timefold.solver.core.impl.domain.variable.ListVariableStateDemand;
 import ai.timefold.solver.core.impl.domain.variable.ListVariableStateSupply;
 import ai.timefold.solver.core.impl.domain.variable.descriptor.ListVariableDescriptor;
@@ -548,6 +549,12 @@ void testIsFeasible() {
         assertThat(kOptListMove.isMoveDoable(scoreDirector)).isFalse();
     }
 
+    @Test
+    void testEnableNearbyMixedModel() {
+        var moveSelectorConfig = new KOptListMoveSelectorConfig();
+        assertThat(moveSelectorConfig.canEnableNearbyInMixedModels()).isTrue();
+    }
+
     /**
      * Create a sequential or non-sequential k-opt from the supplied pairs of undirected removed and added edges.
      *