public static Digraph randomize(Digraph digraph, int order, int size, Random randomizer) {
for (int i = 1; i <= order; i++) digraph.addVertex(new Integer(i));
Random random = randomizer;
int n_2 = order * order;
size = Math.min(size, n_2);
for (int arc = 1; arc <= size; arc++) {
int arcCode = random.nextInt(n_2);
int origin = arcCode / order + 1;
int dst = arcCode % order + 1;
digraph.putArc(new Integer(origin), new Integer(dst), new Integer(arc));
}
return digraph;
}
public static Digraph randomizeAcyclic(
Digraph digraph, int order, int incomingSize, int outgoingSize, Random randomizer) {
Random random = randomizer;
int arc = 1;
for (int i = 1; i <= order; i++) {
Integer destination = new Integer(i);
digraph.addVertex(destination);
for (int j = 0; j < incomingSize; j++) {
int org = random.nextInt(i);
if (org == 0) continue;
Integer origin = new Integer(org);
if (digraph.outgoingSize(origin) >= outgoingSize) continue;
digraph.putArc(origin, destination, new Integer(arc++));
}
}
return digraph;
}
public static Digraph randomizeTree(
Digraph digraph, int maxChildren, int maxLevels, Random randomizer) {
int vertexIndex = 1;
Object root = new Integer(vertexIndex);
List level = Collections.singletonList(root);
digraph.addVertex(root);
for (int i = 1; i < maxLevels; i++) {
List childLevel = new ArrayList(level.size() * maxChildren);
for (Iterator j = level.iterator(); j.hasNext(); ) {
Object parent = j.next();
int childCount = randomizer.nextInt(maxChildren + 1);
for (int k = 0; k < childCount; k++) {
Object child = new Integer(++vertexIndex);
digraph.addVertex(child);
digraph.putArc(parent, child, Boolean.TRUE);
childLevel.add(child);
}
}
if (childLevel.isEmpty()) break;
level = childLevel;
}
return digraph;
}