From b9d67480538ca462363046a4c5f04c8ee8ffa86f Mon Sep 17 00:00:00 2001
From: sbalev <stefan.balev@gmail.com>
Date: Fri, 20 Apr 2012 09:14:48 +0200
Subject: [PATCH] More unit tests

---
 .../generator/test/TestRandomGenerator.java   | 74 ++++++++++++++-----
 1 file changed, 56 insertions(+), 18 deletions(-)

diff --git a/src-test/org/graphstream/algorithm/generator/test/TestRandomGenerator.java b/src-test/org/graphstream/algorithm/generator/test/TestRandomGenerator.java
index caa2b78..04365ea 100644
--- a/src-test/org/graphstream/algorithm/generator/test/TestRandomGenerator.java
+++ b/src-test/org/graphstream/algorithm/generator/test/TestRandomGenerator.java
@@ -3,31 +3,36 @@ package org.graphstream.algorithm.generator.test;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
+import java.util.List;
 import java.util.Random;
 
 import org.graphstream.algorithm.Toolkit;
 import org.graphstream.algorithm.generator.Generator;
 import org.graphstream.algorithm.generator.RandomGenerator;
 import org.graphstream.graph.Graph;
+import org.graphstream.graph.Node;
 import org.graphstream.graph.implementations.AdjacencyListGraph;
 import org.junit.Test;
 
 public class TestRandomGenerator {
+	/**
+	 * Number of nodes 
+	 */
+	public static final int N = 10000;
+	
+	/**
+	 * Average degree
+	 */
+	public static final double K = 49.8765;
 	
 	@Test
 	public void test() {
-		// number of nodes
-		int n = 10000;
-		
-		// average degree
-		double k = 49.8765;
-		
 		Graph g = new AdjacencyListGraph("test");
-		Generator gen = new RandomGenerator(k);
+		Generator gen = new RandomGenerator(K);
 		gen.addSink(g);
 		
 		gen.begin();
-		while (g.getNodeCount() < n) {
+		while (g.getNodeCount() < N) {
 			boolean next = gen.nextEvents();
 			assertTrue(next);
 		}
@@ -35,28 +40,61 @@ public class TestRandomGenerator {
 		gen.removeSink(g);
 		
 		// check if the average degree is k
-		assertEquals(k, Toolkit.averageDegree(g), 0.01 * k);
+		assertEquals(K, Toolkit.averageDegree(g), 0.01 * K);
 		
 		int[] ddR = Toolkit.degreeDistribution(g);
 		
 		// generate Erdos-Reni graph directly
 		g.clear();
-		double p = k / (n - 1);
+		double p = K / (N - 1);
 		Random rnd = new Random();
-		for (int i = 0; i < n; i++)
+		for (int i = 0; i < N; i++)
 			g.addNode(i + "");
-		for (int i = 0; i < n; i++)
-			for (int j = i + 1; j < n; j++)
+		for (int i = 0; i < N; i++)
+			for (int j = i + 1; j < N; j++)
 				if (rnd.nextDouble() < p)
 					g.addEdge(i + "_" + j, i, j);
-		int[] ddE = Toolkit.degreeDistribution(g);
+		int[] ddE1 = Toolkit.degreeDistribution(g);
+		
+		// generate another Erdos-Reni graph more intelligently
+		// this will also test Toolkit.randomNodeSet
+		g.clear();
+		g.addNode("0");
+		for (int i = 1; i < N; i++) {
+			List<Node> l = Toolkit.randomNodeSet(g, p);
+			Node newNode = g.addNode(i + "");
+			for (Node oldNode : l)
+				g.addEdge(oldNode.getId() + "_" + newNode.getId(), oldNode, newNode);
+		}
+		int[] ddE2 = Toolkit.degreeDistribution(g);
 		
 		// compare the distributions
-		int dMax = Math.max(ddR.length, ddE.length);
+		compareDD(ddR, ddE1);
+		compareDD(ddR, ddE2);
+		compareDD(ddE1, ddE2);
+		
+		// finally, generate a graph without edge removal and check only the average degree
+		g.clear();
+		gen = new RandomGenerator(K, false);
+		gen.addSink(g);
+		
+		gen.begin();
+		while (g.getNodeCount() < N) {
+			boolean next = gen.nextEvents();
+			assertTrue(next);
+		}
+		gen.end();
+		gen.removeSink(g);
+
+		assertEquals(K, Toolkit.averageDegree(g), 0.01 * K);		
+	}
+	
+	public void compareDD(int[] dd1, int[] dd2) {
+		int dMax = Math.max(dd1.length, dd2.length);
 		for (int d = 0; d < dMax; d++) {
-			int dR = d < ddR.length ? ddR[d] : 0;
-			int dE = d < ddE.length ? ddE[d] : 0;
-			assertEquals(0, (dR - dE + 0.0) / n, 0.01);
+			int d1 = d < dd1.length ? dd1[d] : 0;
+			int d2 = d < dd2.length ? dd2[d] : 0;
+			assertEquals(0, (d1 - d2 + 0.0) / N, 0.01);
 		}
 	}
 
-- 
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