Feature Parallel ErdosRenyi Generator

networkit/cpp/centrality/test/CentralityGTest.cpp

@@ -1332,7 +1332,7 @@ TEST_F(CentralityGTest, testGroupDegreeUndirected) {
 
 TEST_F(CentralityGTest, testGroupDegreeDirected) {
 	count nodes = 12;
-	ErdosRenyiGenerator gen(nodes, 0.3, true);
+	ErdosRenyiGenerator gen(nodes, 0.3, true, false);
 	Graph g = gen.generate();
 	count k = 5;
 

networkit/cpp/generators/ErdosRenyiGenerator.cpp

@@ -11,8 +11,8 @@
 
 namespace NetworKit {
 
-ErdosRenyiGenerator::ErdosRenyiGenerator(count nNodes, double prob, bool directed) :
-	nNodes{nNodes},	prob{prob}, directed{directed}
+ErdosRenyiGenerator::ErdosRenyiGenerator(count nNodes, double prob, bool directed, bool self_loops) :
+	nNodes{nNodes},	prob{prob}, directed{directed}, self_loops{self_loops}
 {}
 
 Graph ErdosRenyiGenerator::generate() {
@@ -21,6 +21,7 @@ Graph ErdosRenyiGenerator::generate() {
 	{
 		ErdosRenyiEnumeratorDefault impl(nNodes, prob, directed);
 		impl.forEdgesParallel([&](int tid, node u, node v) {
+			if (!self_loops && u == v) return;
 			builder.addHalfEdge(u, v);
 		});
 	}

networkit/cpp/generators/ErdosRenyiGenerator.h

@@ -27,15 +27,18 @@ class ErdosRenyiGenerator: public StaticGraphGenerator {
 	 * @param nNodes Number of nodes n in the graph.
 	 * @param prob Probability of existence for each edge p.
 	 * @param directed	generates a directed graph
+	 * @param self_loops Controls whether a directed graph may contain self_loops
+	 *                   (undirected graphs never have them)
 	 */
-	ErdosRenyiGenerator(count nNodes, double prob, bool directed=false);
+	ErdosRenyiGenerator(count nNodes, double prob, bool directed=false, bool self_loops=true);
 
 	virtual Graph generate();
 
 private:
 	node nNodes;
 	double prob;
 	bool directed;
+	bool self_loops;
 };
 
 } /* namespace NetworKit */