@Override
public Clustering<E, C> reduce(
Clustering[] clusts, Algorithm<E, C> alg, ColorGenerator cg, Props props) {
int k = props.getInt(KMeans.K);
Clustering<E, C> result = new ClusterList<>(k); // reducer - find consensus
// vote about final result
E curr;
Iterator<E> it = clusts[0].instancesIterator();
Cluster<E> cluster;
int[][] mapping = findMapping(clusts, k, alg.getDistanceFunction());
if (cg != null) {
cg.reset();
}
int idx;
while (it.hasNext()) {
curr = it.next();
int[] assign = new int[k];
for (int i = 0; i < clusts.length; i++) {
cluster = clusts[i].assignedCluster(curr);
if (i > 0) {
assign[map(mapping, i, cluster.getClusterId())]++;
} else {
assign[cluster.getClusterId()]++;
}
}
idx = findMax(assign);
// check if cluster already exists
if (!result.hasAt(idx)) {
result.createCluster(idx);
if (cg != null) {
result.get(idx).setColor(cg.next());
}
}
// final cluster assignment
result.get(idx).add(curr);
}
result.compact();
return result;
}
@Override
public String runMetis(Graph graph, int k, Props params) {
long current = System.currentTimeMillis();
File file = new File("inputGraph-" + current);
String filename = file.getName();
Process p;
try {
graph.hMetisExport(file, false);
if (metisFile == null) {
// fetch the file just once
metisFile = getBinary();
System.out.println("metis path: " + metisFile.getAbsolutePath());
}
// run metis
String space = " ";
StringBuilder sb = new StringBuilder(metisFile.getAbsolutePath());
sb.append(" ")
.append(filename)
.append(" ")
.append(String.valueOf(k))
.append(space)
.append("-ufactor=")
.append(String.valueOf(params.getDouble(UFACTOR, 5.0)))
.append(space)
.append("-nruns=")
.append(String.valueOf(params.getInt(NRUNS, 10)))
.append(space)
.append("-ptype=")
.append(String.valueOf(params.get(PTYPE, "rb")))
.append(space)
.append("-otype=")
.append(String.valueOf(params.get(OTYPE, "cut")))
.append(space);
if (params.containsKey(CTYPE)) {
sb.append("-ctype=").append(params.get(CTYPE)).append(space);
}
if (params.containsKey(RTYPE)) {
sb.append("-rtype=").append(params.get(RTYPE)).append(space);
}
// sb.append(String.valueOf(vcycle)).append(space);
p = Runtime.getRuntime().exec(sb.toString());
p.waitFor();
if (debug) {
System.out.println("cmd: " + sb.toString());
System.out.println("exit code: " + p.exitValue());
if (p.exitValue() != 1) {
// System.out.println(ExtBinHelper.readFile(file));
}
helper.readStdout(p);
helper.readStderr(p);
}
file.delete();
} catch (FileNotFoundException | UnsupportedEncodingException ex) {
Exceptions.printStackTrace(ex);
} catch (IOException | InterruptedException ex) {
Exceptions.printStackTrace(ex);
}
return filename;
}
@Override
public Clustering<E, C> reduce(
Clustering[] clusts, Algorithm<E, C> alg, ColorGenerator cg, Props props) {
Graph graph = createGraph(clusts);
// degree of freedom
double df;
double w, attain;
EdgeIterable neigh;
PriorityQueue<DoubleElem> pq = new PriorityQueue<>(graph.getNodeCount());
DoubleElem<Node> elem;
// for each node compute attainment score
for (Node node : graph.getNodes()) {
neigh = graph.getEdges(node);
df = neigh.size();
w = 0.0;
for (Edge ne : neigh) {
w += ne.getWeight();
}
attain = w / df;
elem = new DoubleElem<>(node, attain);
pq.add(elem);
}
// number of clusters is just a hint
int k = props.getInt(KMeans.K, 5);
double relax = props.getDouble(RELAX, 0.5);
Clustering<E, C> result = new ClusterList(k);
Dataset<? extends Instance> dataset = clusts[0].getLookup().lookup(Dataset.class);
result.lookupAdd(dataset);
ObjectOpenHashSet<Node> blacklist = new ObjectOpenHashSet();
Node node, other;
Cluster curr;
double maxW;
while (!pq.isEmpty()) {
elem = pq.poll();
node = elem.getElem();
if (!blacklist.contains(node)) {
blacklist.add(node);
curr = result.createCluster();
if (cg != null) {
curr.setColor(cg.next());
}
curr.add(node.getInstance());
EdgeIterable iter = graph.getEdges(node);
maxW = -1;
for (Edge ne : iter) {
if (ne.getWeight() > maxW) {
maxW = ne.getWeight();
}
}
// add immediate neighbours with max weight to same cluster
if (maxW >= 0.0) {
for (Edge ne : iter) {
// when relax set to 0.0, only items with maximum weight
// will be added to the same cluster
w = ne.getWeight() + relax * ne.getWeight();
if (w >= maxW) {
if (!node.equals(ne.getSource())) {
other = ne.getSource();
} else {
other = ne.getTarget();
}
if (!blacklist.contains(other)) {
curr.add(other.getInstance());
blacklist.add(other);
}
}
}
}
}
}
// TODO merge some clusters
return result;
}