[SPARK-3263][GraphX] Fix changes made to GraphGenerator.logNormalGraph in PR #720

PR #720 made multiple changes to GraphGenerator.logNormalGraph including:

* Replacing the call to functions for generating random vertices and edges with in-line implementations with different equations. Based on reading the Pregel paper, I believe the in-line functions are incorrect.
* Hard-coding of RNG seeds so that method now generates the same graph for a given number of vertices, edges, mu, and sigma -- user is not able to override seed or specify that seed should be randomly generated.
* Backwards-incompatible change to logNormalGraph signature with introduction of new required parameter.
* Failed to update scala docs and programming guide for API changes
* Added a Synthetic Benchmark in the examples.

This PR:
* Removes the in-line calls and calls original vertex / edge generation functions again
* Adds an optional seed parameter for deterministic behavior (when desired)
* Keeps the number of partitions parameter that was added.
* Keeps compatibility with the synthetic benchmark example
* Maintains backwards-compatible API

Author: RJ Nowling <rnowling@gmail.com>
Author: Ankur Dave <ankurdave@gmail.com>

Closes #2168 from rnowling/graphgenrand and squashes the following commits:

f1cd79f [Ankur Dave] Style fixes
e11918e [RJ Nowling] Fix bad comparisons in unit tests
785ac70 [RJ Nowling] Fix style error
c70868d [RJ Nowling] Fix logNormalGraph scala doc for seed
41fd1f8 [RJ Nowling] Fix logNormalGraph scala doc for seed
799f002 [RJ Nowling] Added test for different seeds for sampleLogNormal
43949ad [RJ Nowling] Added test for different seeds for generateRandomEdges
2faf75f [RJ Nowling] Added unit test for logNormalGraph
82f22397 [RJ Nowling] Add unit test for sampleLogNormal
b99cba9 [RJ Nowling] Make sampleLogNormal private to Spark (vs private) for unit testing
6803da1 [RJ Nowling] Add GraphGeneratorsSuite with test for generateRandomEdges
1c8fc44 [RJ Nowling] Connected components part of SynthBenchmark was failing to call count on RDD before printing
dfbb6dd [RJ Nowling] Fix parameter name in SynthBenchmark docs
b5eeb80 [RJ Nowling] Add optional seed parameter to SynthBenchmark and set default to randomly generate a seed
1ff8d30 [RJ Nowling] Fix bug in generateRandomEdges where numVertices instead of numEdges was used to control number of edges to generate
98bb73c [RJ Nowling] Add documentation for logNormalGraph parameters
d40141a [RJ Nowling] Fix style error
684804d [RJ Nowling] revert PR #720 which introduce errors in logNormalGraph and messed up seeding of RNGs.  Add user-defined optional seed for deterministic behavior
c183136 [RJ Nowling] Fix to deterministic GraphGenerators.logNormalGraph that allows generating graphs randomly using optional seed.
015010c [RJ Nowling] Fixed GraphGenerator logNormalGraph API to make backward-incompatible change in commit 894ecde04

1 files changed, 110 insertions, 0 deletions

diff --git a/graphx/src/test/scala/org/apache/spark/graphx/util/GraphGeneratorsSuite.scala b/graphx/src/test/scala/org/apache/spark/graphx/util/GraphGeneratorsSuite.scala
new file mode 100644
index 0000000000..b346d4db2e
--- /dev/null
+++ b/graphx/src/test/scala/org/apache/spark/graphx/util/GraphGeneratorsSuite.scala
@@ -0,0 +1,110 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.spark.graphx.util
+
+import org.scalatest.FunSuite
+
+import org.apache.spark.graphx.LocalSparkContext
+
+class GraphGeneratorsSuite extends FunSuite with LocalSparkContext {
+
+  test("GraphGenerators.generateRandomEdges") {
+    val src = 5
+    val numEdges10 = 10
+    val numEdges20 = 20
+    val maxVertexId = 100
+
+    val edges10 = GraphGenerators.generateRandomEdges(src, numEdges10, maxVertexId)
+    assert(edges10.length == numEdges10)
+
+    val correctSrc = edges10.forall(e => e.srcId == src)
+    assert(correctSrc)
+
+    val correctWeight = edges10.forall(e => e.attr == 1)
+    assert(correctWeight)
+
+    val correctRange = edges10.forall(e => e.dstId >= 0 && e.dstId <= maxVertexId)
+    assert(correctRange)
+
+    val edges20 = GraphGenerators.generateRandomEdges(src, numEdges20, maxVertexId)
+    assert(edges20.length == numEdges20)
+
+    val edges10_round1 =
+      GraphGenerators.generateRandomEdges(src, numEdges10, maxVertexId, seed = 12345)
+    val edges10_round2 =
+      GraphGenerators.generateRandomEdges(src, numEdges10, maxVertexId, seed = 12345)
+    assert(edges10_round1.zip(edges10_round2).forall { case (e1, e2) =>
+      e1.srcId == e2.srcId && e1.dstId == e2.dstId && e1.attr == e2.attr
+    })
+
+    val edges10_round3 =
+      GraphGenerators.generateRandomEdges(src, numEdges10, maxVertexId, seed = 3467)
+    assert(!edges10_round1.zip(edges10_round3).forall { case (e1, e2) =>
+      e1.srcId == e2.srcId && e1.dstId == e2.dstId && e1.attr == e2.attr
+    })
+  }
+
+  test("GraphGenerators.sampleLogNormal") {
+    val mu = 4.0
+    val sigma = 1.3
+    val maxVal = 100
+
+    val dstId = GraphGenerators.sampleLogNormal(mu, sigma, maxVal)
+    assert(dstId < maxVal)
+
+    val dstId_round1 = GraphGenerators.sampleLogNormal(mu, sigma, maxVal, 12345)
+    val dstId_round2 = GraphGenerators.sampleLogNormal(mu, sigma, maxVal, 12345)
+    assert(dstId_round1 == dstId_round2)
+
+    val dstId_round3 = GraphGenerators.sampleLogNormal(mu, sigma, maxVal, 789)
+    assert(dstId_round1 != dstId_round3)
+  }
+
+  test("GraphGenerators.logNormalGraph") {
+    withSpark { sc =>
+      val mu = 4.0
+      val sigma = 1.3
+      val numVertices100 = 100
+
+      val graph = GraphGenerators.logNormalGraph(sc, numVertices100, mu = mu, sigma = sigma)
+      assert(graph.vertices.count() == numVertices100)
+
+      val graph_round1 =
+        GraphGenerators.logNormalGraph(sc, numVertices100, mu = mu, sigma = sigma, seed = 12345)
+      val graph_round2 =
+        GraphGenerators.logNormalGraph(sc, numVertices100, mu = mu, sigma = sigma, seed = 12345)
+
+      val graph_round1_edges = graph_round1.edges.collect()
+      val graph_round2_edges = graph_round2.edges.collect()
+
+      assert(graph_round1_edges.zip(graph_round2_edges).forall { case (e1, e2) =>
+        e1.srcId == e2.srcId && e1.dstId == e2.dstId && e1.attr == e2.attr
+      })
+
+      val graph_round3 =
+        GraphGenerators.logNormalGraph(sc, numVertices100, mu = mu, sigma = sigma, seed = 567)
+
+      val graph_round3_edges = graph_round3.edges.collect()
+
+      assert(!graph_round1_edges.zip(graph_round3_edges).forall { case (e1, e2) =>
+        e1.srcId == e2.srcId && e1.dstId == e2.dstId && e1.attr == e2.attr
+      })
+    }
+  }
+
+}