Add label propagation in compute facade

Author: IoannisPanagiotas

algo/src/main/java/org/neo4j/gds/labelpropagation/LabelPropagationResult.java

@@ -21,4 +21,7 @@
 
 import org.neo4j.gds.collections.ha.HugeLongArray;
 
-public record LabelPropagationResult(HugeLongArray labels, boolean didConverge, long ranIterations) {}
+public record LabelPropagationResult(HugeLongArray labels, boolean didConverge, long ranIterations) {
+
+    public static LabelPropagationResult EMPTY = new LabelPropagationResult(HugeLongArray.newArray(0), false, 0);
+}

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

@@ -47,6 +47,9 @@
 import org.neo4j.gds.kmeans.KmeansContext;
 import org.neo4j.gds.kmeans.KmeansParameters;
 import org.neo4j.gds.kmeans.KmeansResult;
+import org.neo4j.gds.labelpropagation.LabelPropagation;
+import org.neo4j.gds.labelpropagation.LabelPropagationParameters;
+import org.neo4j.gds.labelpropagation.LabelPropagationResult;
 import org.neo4j.gds.result.TimedAlgorithmResult;
 import org.neo4j.gds.termination.TerminationFlag;
 
@@ -301,4 +304,36 @@ CompletableFuture<TimedAlgorithmResult<KmeansResult>> kMeans(
         );
     }
 
+    CompletableFuture<TimedAlgorithmResult<LabelPropagationResult>> labelPropagation(
+        Graph graph,
+        LabelPropagationParameters parameters,
+        JobId jobId,
+        boolean logProgress
+    ) {
+
+        if (graph.isEmpty()) {
+            return CompletableFuture.completedFuture(TimedAlgorithmResult.empty(LabelPropagationResult.EMPTY));
+        }
+
+        var progressTracker = progressTrackerFactory.create(
+            tasks.labelPropagation(graph,parameters),
+            jobId,
+            parameters.concurrency(),
+            logProgress
+        );
+
+        var algorithm = new LabelPropagation(
+            graph,
+            parameters,
+            DefaultPool.INSTANCE,
+            progressTracker,
+            terminationFlag
+        );
+
+        return algorithmCaller.run(
+            algorithm::compute,
+            jobId
+        );
+    }
+
 }

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

@@ -41,6 +41,8 @@
 import org.neo4j.gds.kcore.KCoreDecompositionParameters;
 import org.neo4j.gds.kcore.KCoreDecompositionResult;
 import org.neo4j.gds.kmeans.KmeansParameters;
+import org.neo4j.gds.labelpropagation.LabelPropagationParameters;
+import org.neo4j.gds.labelpropagation.LabelPropagationResult;
 import org.neo4j.gds.termination.TerminationFlag;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -193,4 +195,20 @@ void kMeans(){
         verifyNoInteractions(algorithmCallerMock);
     }
 
+    @Test
+    void labelPropagation(){
+
+        var future = facade.labelPropagation(
+            graph,
+            mock(LabelPropagationParameters.class),
+            jobIdMock,
+            false
+        );
+
+        var results = future.join();
+
+        assertThat(results.result()).isEqualTo(LabelPropagationResult.EMPTY);
+        verifyNoInteractions(progressTrackerFactoryMock);
+        verifyNoInteractions(algorithmCallerMock);
+    }
 }

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

@@ -44,6 +44,7 @@
 import org.neo4j.gds.kcore.KCoreDecompositionParameters;
 import org.neo4j.gds.kmeans.KmeansParameters;
 import org.neo4j.gds.kmeans.SamplerType;
+import org.neo4j.gds.labelpropagation.LabelPropagationParameters;
 import org.neo4j.gds.logging.Log;
 import org.neo4j.gds.termination.TerminationFlag;
 
@@ -247,4 +248,24 @@ void kMeans(){
         assertThat(results.computeMillis()).isNotNegative();
     }
 
+    @Test
+    void labelPropagation(){
+        var future = facade.labelPropagation(
+            graph,
+            new LabelPropagationParameters(
+                new Concurrency(4),
+                10,
+                null,
+                null
+            ),
+            jobIdMock,
+            false
+        );
+
+        var results = future.join();
+
+        assertThat(results.result().ranIterations()).isGreaterThan(0);
+        assertThat(results.computeMillis()).isNotNegative();
+    }
+
 }