fix: only run local search when there is something to run

TimefoldAI · Feb 3, 2025 · f3b830c · f3b830c
1 parent 8837b33
commit f3b830c
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Showing 3 changed files with 11 additions and 2 deletions.
diff --git a/core/src/main/java/ai/timefold/solver/core/impl/localsearch/DefaultLocalSearchPhase.java b/core/src/main/java/ai/timefold/solver/core/impl/localsearch/DefaultLocalSearchPhase.java
@@ -54,6 +54,15 @@ public String getPhaseTypeString() {
 
     @Override
     public void solve(SolverScope<Solution_> solverScope) {
+        var hasAnythingToImprove = solverScope.getProblemSizeStatistics().approximateProblemSizeLog() != 0.0;
+        if (!hasAnythingToImprove) {
+            // Reaching local search means that the solution is already fully initialized.
+            // Yet the problem size indicates there is only 1 possible solution.
+            // Therefore, this solution must be it and there is nothing to improve.
+            logger.info("{}Local Search phase ({}) has no entities or values to move.", logIndentation, phaseIndex);
+            return;
+        }
+
         LocalSearchPhaseScope<Solution_> phaseScope = new LocalSearchPhaseScope<>(solverScope, phaseIndex);
         phaseStarted(phaseScope);
 

diff --git a/core/src/main/java/ai/timefold/solver/core/impl/solver/AbstractSolver.java b/core/src/main/java/ai/timefold/solver/core/impl/solver/AbstractSolver.java
@@ -65,6 +65,8 @@ public void solvingStarted(SolverScope<Solution_> solverScope) {
         bestSolutionRecaller.solvingStarted(solverScope);
         solverTermination.solvingStarted(solverScope);
         phaseLifecycleSupport.fireSolvingStarted(solverScope);
+        solverScope.setProblemSizeStatistics(
+                solverScope.getSolutionDescriptor().getProblemSizeStatistics(solverScope.getWorkingSolution()));
         for (Phase<Solution_> phase : phaseList) {
             phase.solvingStarted(solverScope);
         }

diff --git a/core/src/main/java/ai/timefold/solver/core/impl/solver/DefaultSolver.java b/core/src/main/java/ai/timefold/solver/core/impl/solver/DefaultSolver.java
@@ -245,8 +245,6 @@ public void solvingStarted(SolverScope<Solution_> solverScope) {
     }
 
     private void registerSolverSpecificMetrics() {
-        solverScope.setProblemSizeStatistics(
-                solverScope.getSolutionDescriptor().getProblemSizeStatistics(solverScope.getWorkingSolution()));
         solverScope.getSolverMetricSet().forEach(solverMetric -> solverMetric.register(this));
     }