Add modularity optimization in compute facade

Author: IoannisPanagiotas

algo/src/main/java/org/neo4j/gds/modularityoptimization/ModularityOptimizationResult.java

@@ -48,4 +48,12 @@ public long nodeCount() {
             }
         };
     }
+
+    public static ModularityOptimizationResult EMPTY = new ModularityOptimizationResult(
+         i -> 0,
+        0,
+        0,
+        false,
+        0
+    );
 }

algorithms-compute-facade/src/main/java/org/neo4j/gds/community/CommunityComputeFacade.java

@@ -60,6 +60,9 @@
 import org.neo4j.gds.modularity.ModularityCalculator;
 import org.neo4j.gds.modularity.ModularityParameters;
 import org.neo4j.gds.modularity.ModularityResult;
+import org.neo4j.gds.modularityoptimization.ModularityOptimization;
+import org.neo4j.gds.modularityoptimization.ModularityOptimizationParameters;
+import org.neo4j.gds.modularityoptimization.ModularityOptimizationResult;
 import org.neo4j.gds.result.TimedAlgorithmResult;
 import org.neo4j.gds.termination.TerminationFlag;
 import org.neo4j.gds.triangle.LocalClusteringCoefficient;
@@ -473,4 +476,44 @@ CompletableFuture<TimedAlgorithmResult<ModularityResult>> modularity(
         );
     }
 
+    CompletableFuture<TimedAlgorithmResult<ModularityOptimizationResult>> modularityOptimization(
+        Graph graph,
+        ModularityOptimizationParameters parameters,
+        JobId jobId,
+        boolean logProgress
+    ) {
+
+        if (graph.isEmpty()) {
+            return CompletableFuture.completedFuture(TimedAlgorithmResult.empty(ModularityOptimizationResult.EMPTY));
+        }
+
+        var progressTracker = progressTrackerFactory.create(
+            tasks.modularityOptimization(graph,parameters),
+            jobId,
+            parameters.concurrency(),
+            logProgress
+        );
+
+        var seedPropertyValues = parameters.seedProperty()
+            .map(seedProperty -> CommunityCompanion.extractSeedingNodePropertyValues(graph, seedProperty))
+            .orElse(null);
+
+        var algorithm = new ModularityOptimization(
+            graph,
+            parameters.maxIterations(),
+            parameters.tolerance(),
+            seedPropertyValues,
+            parameters.concurrency(),
+            parameters.batchSize(),
+            DefaultPool.INSTANCE,
+            progressTracker,
+            terminationFlag
+        );
+
+        return algorithmCaller.run(
+            algorithm::compute,
+            jobId
+        );
+    }
+
 }

algorithms-compute-facade/src/test/java/org/neo4j/gds/community/CommunityComputeFacadeEmptyGraphTest.java

@@ -49,6 +49,8 @@
 import org.neo4j.gds.louvain.LouvainResult;
 import org.neo4j.gds.modularity.ModularityParameters;
 import org.neo4j.gds.modularity.ModularityResult;
+import org.neo4j.gds.modularityoptimization.ModularityOptimizationParameters;
+import org.neo4j.gds.modularityoptimization.ModularityOptimizationResult;
 import org.neo4j.gds.termination.TerminationFlag;
 import org.neo4j.gds.triangle.LocalClusteringCoefficientParameters;
 import org.neo4j.gds.triangle.LocalClusteringCoefficientResult;
@@ -286,4 +288,21 @@ void modularity(){
         verifyNoInteractions(progressTrackerFactoryMock);
         verifyNoInteractions(algorithmCallerMock);
     }
+
+    @Test
+    void modularityOptimization(){
+
+        var future = facade.modularityOptimization(
+            graph,
+            mock(ModularityOptimizationParameters.class),
+            jobIdMock,
+            false
+        );
+
+        var results = future.join();
+
+        assertThat(results.result()).isEqualTo(ModularityOptimizationResult.EMPTY);
+        verifyNoInteractions(progressTrackerFactoryMock);
+        verifyNoInteractions(algorithmCallerMock);
+    }
 }

algorithms-compute-facade/src/test/java/org/neo4j/gds/community/CommunityComputeFacadeTest.java

@@ -49,6 +49,7 @@
 import org.neo4j.gds.logging.Log;
 import org.neo4j.gds.louvain.LouvainParameters;
 import org.neo4j.gds.modularity.ModularityParameters;
+import org.neo4j.gds.modularityoptimization.ModularityOptimizationParameters;
 import org.neo4j.gds.termination.TerminationFlag;
 import org.neo4j.gds.triangle.LocalClusteringCoefficientParameters;
 
@@ -354,4 +355,25 @@ void modularity(){
         assertThat(results.computeMillis()).isNotNegative();
     }
 
+    @Test
+    void modularityOptimization(){
+        var future = facade.modularityOptimization(
+            graph,
+            new ModularityOptimizationParameters(
+                new Concurrency(4),
+                10,
+                10_000,
+                0,
+                Optional.empty()
+            ),
+            jobIdMock,
+            false
+        );
+
+        var results = future.join();
+
+        assertThat(results.result().ranIterations()).isGreaterThan(0);
+        assertThat(results.computeMillis()).isNotNegative();
+    }
+
 }