[dbs-leipzig#1571] Added interval calculation and changed tests to ch…

…eck for intervals

gradoop-temporal/src/main/java/org/gradoop/temporal/model/impl/operators/metric/DegreeVarianceEvolution.java

@@ -17,22 +17,20 @@
 
 import org.apache.flink.api.java.DataSet;
 import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.api.java.tuple.Tuple3;
 import org.gradoop.flink.model.api.operators.UnaryBaseGraphToValueOperator;
 import org.gradoop.flink.model.impl.operators.sampling.functions.VertexDegree;
 import org.gradoop.temporal.model.api.TimeDimension;
 import org.gradoop.temporal.model.impl.TemporalGraph;
-import org.gradoop.temporal.model.impl.operators.metric.functions.TransformDeltaToAbsoluteDegreeTree;
-import org.gradoop.temporal.model.impl.operators.metric.functions.FlatMapVertexIdEdgeInterval;
-import org.gradoop.temporal.model.impl.operators.metric.functions.BuildTemporalDegreeTree;
-import org.gradoop.temporal.model.impl.operators.metric.functions.GroupDegreeTreesToVariance;
+import org.gradoop.temporal.model.impl.operators.metric.functions.*;
 
 import java.util.Objects;
 
 /**
  * Operator that calculates the degree variance evolution of a temporal graph for the
  * whole lifetime of the graph.
  */
-public class DegreeVarianceEvolution implements UnaryBaseGraphToValueOperator<TemporalGraph, DataSet<Tuple2<Long, Double>>> {
+public class DegreeVarianceEvolution implements UnaryBaseGraphToValueOperator<TemporalGraph, DataSet<Tuple3<Long, Long, Double>>> {
     /**
      * The time dimension that will be considered.
      */
@@ -55,7 +53,7 @@ public DegreeVarianceEvolution(VertexDegree degreeType, TimeDimension dimension)
     }
 
     @Override
-    public DataSet<Tuple2<Long, Double>> execute(TemporalGraph graph) {
+    public DataSet<Tuple3<Long, Long, Double>> execute(TemporalGraph graph) {
         return graph.getEdges()
                 // 1) Extract vertex id(s) and corresponding time intervals
                 .flatMap(new FlatMapVertexIdEdgeInterval(dimension, degreeType))
@@ -66,6 +64,7 @@ public DataSet<Tuple2<Long, Double>> execute(TemporalGraph graph) {
                 // 4) Transform each tree to aggregated evolution
                 .map(new TransformDeltaToAbsoluteDegreeTree())
                 // 6) Merge trees together and calculate aggregation
-                .reduceGroup(new GroupDegreeTreesToVariance());
+                .reduceGroup(new GroupDegreeTreesToVariance())
+                .mapPartition(new MapDegreesToInterval());
     }
 }

gradoop-temporal/src/main/java/org/gradoop/temporal/model/impl/operators/metric/functions/GroupDegreeTreesToVariance.java

@@ -64,9 +64,9 @@ public void reduce(Iterable<Tuple2<GradoopId, TreeMap<Long, Integer>>> iterable,
 
         for (Long timePoint : timePoints) {
             // skip last default time
-            if (Long.MAX_VALUE == timePoint) {
+           /* if (Long.MAX_VALUE == timePoint) {
                 continue;
-            }
+            }*/
             // Iterate over all vertices
             for (Map.Entry<GradoopId, TreeMap<Long, Integer>> entry : degreeTrees.entrySet()) {
                 // Make sure the vertex is registered in the current vertexDegrees capture
@@ -85,12 +85,15 @@ public void reduce(Iterable<Tuple2<GradoopId, TreeMap<Long, Integer>>> iterable,
                 }
             }
 
+            //sum of the degrees of all vertices
             Optional<Integer> opt = vertexDegrees.values().stream().reduce(Math::addExact);
             Optional<Double> opt2 = Optional.empty();
 
             double mean;
 
+            //if we have a sum at the current timestamp
             if (opt.isPresent()) {
+                //calculate the avg degree of the graph at the current timestamp
                 mean = (double) opt.get() / (double) numberOfVertices;
                 opt2 = Optional.of(vertexDegrees.values().stream()
                         .mapToDouble(val -> (val - mean) * (val - mean)).sum());

gradoop-temporal/src/main/java/org/gradoop/temporal/model/impl/operators/metric/functions/MapDegreesToInterval.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2014 - 2021 Leipzig University (Database Research Group)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.gradoop.temporal.model.impl.operators.metric.functions;
+
+import org.apache.flink.api.common.functions.MapPartitionFunction;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.api.java.tuple.Tuple3;
+import org.apache.flink.util.Collector;
+
+/**
+ * A map partition function that calculates the intervals in which the values stay the same
+ * by checking if the current value is the same as the previous one
+ *
+ */
+
+public class MapDegreesToInterval implements MapPartitionFunction<Tuple2<Long, Double>, Tuple3<Long, Long, Double>> {
+    @Override
+    public void mapPartition(Iterable<Tuple2<Long, Double>> values, Collector<Tuple3<Long, Long, Double>> out) {
+
+        //set starting values to null
+        Long startTimestamp = null;
+        Long endTimestamp = null;
+        Double value = null;
+        Boolean collected = false;
+
+        //loop through each tuple
+        for (Tuple2<Long, Double> tuple : values) {
+            if (startTimestamp == null) {
+                // First element in the group
+                startTimestamp = tuple.f0;
+                endTimestamp = tuple.f0;
+                value = tuple.f1;
+            } else {
+                if (!tuple.f1.equals(value)) {
+                    // Value changed, emit the current interval and start a new one
+                    out.collect(new Tuple3<>(startTimestamp, tuple.f0, value));
+                    startTimestamp = tuple.f0;
+                    endTimestamp = tuple.f0;
+                    value = tuple.f1;
+                    collected = true;
+                } else {
+                    // Extend the current interval
+                    endTimestamp = tuple.f0;
+                    collected = false;
+                }
+            }
+        }
+        //check if the latest interval was collected, if not, collect it
+        //this happens when the last interval has the value 0
+        if (!collected) {
+            out.collect(new Tuple3<>(startTimestamp, endTimestamp, value));
+        }
+    }
+}

gradoop-temporal/src/test/java/org/gradoop/temporal/model/impl/operators/metric/DegreeVarianceEvolutionTest.java

@@ -19,6 +19,7 @@
 import org.apache.flink.api.java.DataSet;
 import org.apache.flink.api.java.io.LocalCollectionOutputFormat;
 import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.api.java.tuple.Tuple3;
 import org.gradoop.common.model.impl.id.GradoopId;
 import org.gradoop.flink.model.impl.operators.sampling.functions.VertexDegree;
 import org.gradoop.temporal.model.api.TimeDimension;
@@ -42,40 +43,66 @@ public class DegreeVarianceEvolutionTest extends TemporalGradoopTestBase {
     /**
      * The expected in-degrees for each vertex label.
      */
-    private static final List<Tuple2<Long, Double>> EXPECTED_IN_DEGREES = new ArrayList<>();
+    private static final List<Tuple3<Long, Long, Double>> EXPECTED_IN_DEGREES = new ArrayList<>();
     /**
      * The expected out-degrees for each vertex label.
      */
-    private static final List<Tuple2<Long, Double>> EXPECTED_OUT_DEGREES = new ArrayList<>();
+    private static final List<Tuple3<Long, Long, Double>> EXPECTED_OUT_DEGREES = new ArrayList<>();
     /**
      * The expected degrees for each vertex label.
      */
-    private static final List<Tuple2<Long, Double>> EXPECTED_BOTH_DEGREES = new ArrayList<>();
+    private static final List<Tuple3<Long, Long, Double>> EXPECTED_BOTH_DEGREES = new ArrayList<>();
 
     static {
         // IN DEGREES
+        /*
         EXPECTED_IN_DEGREES.add(new Tuple2<>(Long.MIN_VALUE, 0.0));
         EXPECTED_IN_DEGREES.add(new Tuple2<>(0L, 0.1875));
         EXPECTED_IN_DEGREES.add(new Tuple2<>(4L, 0.5));
         EXPECTED_IN_DEGREES.add(new Tuple2<>(5L, 0.25));
         EXPECTED_IN_DEGREES.add(new Tuple2<>(6L, 0.25));
         EXPECTED_IN_DEGREES.add(new Tuple2<>(7L, 0.1875));
+        */
+        EXPECTED_IN_DEGREES.add(new Tuple3<>(Long.MIN_VALUE, 0L, 0.0));
+        EXPECTED_IN_DEGREES.add(new Tuple3<>(0L, 4L, 0.1875));
+        EXPECTED_IN_DEGREES.add(new Tuple3<>(4L, 5L, 0.5));
+        EXPECTED_IN_DEGREES.add(new Tuple3<>(5L, 7L, 0.25));
+        EXPECTED_IN_DEGREES.add(new Tuple3<>(7L, Long.MAX_VALUE, 0.1875));
+
+
 
         // OUT DEGREES
+        EXPECTED_OUT_DEGREES.add(new Tuple3<>(Long.MIN_VALUE, 0L, 0.0));
+        EXPECTED_OUT_DEGREES.add(new Tuple3<>(0L, 4L, 0.1875));
+        EXPECTED_OUT_DEGREES.add(new Tuple3<>(4L, 5L, 0.5));
+        EXPECTED_OUT_DEGREES.add(new Tuple3<>(5L, 7L, 0.25));
+        EXPECTED_OUT_DEGREES.add(new Tuple3<>(7L, Long.MAX_VALUE, 0.1875));
+
+        /*
         EXPECTED_OUT_DEGREES.add(new Tuple2<>(Long.MIN_VALUE, 0.0));
         EXPECTED_OUT_DEGREES.add(new Tuple2<>(0L, 0.1875));
         EXPECTED_OUT_DEGREES.add(new Tuple2<>(4L, 0.5));
         EXPECTED_OUT_DEGREES.add(new Tuple2<>(5L, 0.25));
         EXPECTED_OUT_DEGREES.add(new Tuple2<>(6L, 0.25));
         EXPECTED_OUT_DEGREES.add(new Tuple2<>(7L, 0.1875));
+         */
 
         // DEGREES
+        EXPECTED_BOTH_DEGREES.add(new Tuple3<>(Long.MIN_VALUE, 0L, 0.0));
+        EXPECTED_BOTH_DEGREES.add(new Tuple3<>(0L, 4L, 0.24000000000000005));
+        EXPECTED_BOTH_DEGREES.add(new Tuple3<>(4L, 5L, 0.64));
+        EXPECTED_BOTH_DEGREES.add(new Tuple3<>(5L, 6L, 0.16));
+        EXPECTED_BOTH_DEGREES.add(new Tuple3<>(6L, 7L, 0.56));
+        EXPECTED_BOTH_DEGREES.add(new Tuple3<>(7L, Long.MAX_VALUE, 0.24000000000000005));
+
+        /*
         EXPECTED_BOTH_DEGREES.add(new Tuple2<>(Long.MIN_VALUE, 0.0));
         EXPECTED_BOTH_DEGREES.add(new Tuple2<>(0L, 0.24000000000000005));
         EXPECTED_BOTH_DEGREES.add(new Tuple2<>(4L, 0.64));
         EXPECTED_BOTH_DEGREES.add(new Tuple2<>(5L, 0.16));
         EXPECTED_BOTH_DEGREES.add(new Tuple2<>(6L, 0.56));
         EXPECTED_BOTH_DEGREES.add(new Tuple2<>(7L, 0.24000000000000005));
+        */
     }
 
     /**
@@ -130,9 +157,9 @@ public void setUp() throws Exception {
      */
     @Test
     public void testDegreeVariance() throws Exception {
-        Collection<Tuple2<Long, Double>> resultCollection = new ArrayList<>();
+        Collection<Tuple3<Long, Long, Double>> resultCollection = new ArrayList<>();
 
-        final DataSet<Tuple2<Long, Double>> resultDataSet = testGraph
+        final DataSet<Tuple3<Long, Long, Double>> resultDataSet = testGraph
                 .callForValue(new DegreeVarianceEvolution(degreeType, TimeDimension.VALID_TIME));
 
         resultDataSet.output(new LocalCollectionOutputFormat<>(resultCollection));