public void cleanup(Context context) throws IOException, InterruptedException {
float normHubVal = (float) 0.0;
float normSpokeVal = (float) 0.0;
// Calculate Sum of Squares of Each nodes Hub And spoke value
for (Text nid : map.keySet()) {
NodeWritable n = map.get(nid);
normHubVal += Math.pow(n.getHubVal().get(), 2);
normSpokeVal += Math.pow(n.getSpokeVal().get(), 2);
}
// Normalize the Hub And Spoke values and Emit for next iteration
for (Text nid : map.keySet()) {
NodeWritable n = map.get(nid);
n.getHubVal().set((float) (n.getHubVal().get() / Math.sqrt(normHubVal)));
n.getSpokeVal().set((float) (n.getSpokeVal().get() / Math.sqrt(normSpokeVal)));
context.write(n, new Text());
}
}
public void reduce(Text key, Iterable<Text> values, Context context)
throws IOException, InterruptedException {
NodeWritable n = new NodeWritable();
n.setNid(key);
for (Text value : values) {
String[] valueArray = value.toString().split(",");
String flag = valueArray[0];
if (flag.equals("In")) {
NodeWritable x = new NodeWritable();
x.setNid(new Text(valueArray[1]));
n.addInNode(x);
} else {
NodeWritable x = new NodeWritable();
x.setNid(new Text(valueArray[1]));
n.addOutNode(x);
}
}
context.write(n, new Text());
}
@Override
public void reduce(
Text key,
Iterator<NodeWritable> values,
OutputCollector<Text, NodeWritable> output,
Reporter reporter)
throws IOException {
// The nodes are either the node definition or possible distances to the
// node.
// For a given key, there should be a single node definition and
// multiple distances.
// Find the node definition and the minimum distance.
int minDistance = Integer.MAX_VALUE;
NodeWritable theNode = new NodeWritable();
while (values.hasNext()) {
NodeWritable nextNode = values.next();
if (nextNode.isNode()) {
// There should only be one per key since the mapper emits the node once to
// preserve the graph from one iteration to another.
theNode.setNode(nextNode);
}
if (nextNode.isDistanceKnown() && nextNode.getDistance() < minDistance) {
minDistance = nextNode.getDistance();
}
}
if (minDistance != Integer.MAX_VALUE) {
// We found the minimum
theNode.setDistance(minDistance);
// Increment a counter indicating that the shortest path to the
// node has been found.
reporter.getCounter("node", "nodeDistanceSet").increment(1);
}
// output the node with the distance updated.
output.collect(key, theNode);
}
// reduce(nid m, [d1,d2,...])
public void reduce(Text key, Iterable<NodeWritable> values, Context context)
throws IOException, InterruptedException {
float spokeVal = 0.0f;
float hubVal = 0.0f;
ArrayList<NodeWritable> arr = new ArrayList<NodeWritable>();
NodeWritable M = null;
// Extract Original Node from Values
for (NodeWritable x : values) {
if (x.getNid().toString().equals(key.toString())) {
M = new NodeWritable(x.toString());
break;
}
}
// Store All Values in arr
for (NodeWritable x : values) {
arr.add(x);
}
// Create List of All In Nodes
ArrayList<NodeWritable> ins = new ArrayList<NodeWritable>();
// Create List of all Out Nodes
ArrayList<NodeWritable> outs = new ArrayList<NodeWritable>();
// Populate Above Lists
for (NodeWritable x : arr) {
if (!x.getIsInList().toString().equals("***")) {
if (x.getIsInList().toString().equals("YES")) {
ins.add(x);
} else {
if (x.getIsInList().toString().equals("NO")) {
outs.add(x);
}
}
}
}
// For Each Out nodes change the current hubVal
for (NodeWritable t : outs) {
hubVal += Float.parseFloat(t.getSpokeVal().toString());
}
// For Each In Nodes change current spokeVal
for (NodeWritable t : ins) {
spokeVal += (Float.parseFloat(t.getHubVal().toString()));
}
// Set new Hub value
M.getHubVal().set(hubVal);
// Set new Spoke Value
M.getSpokeVal().set(spokeVal);
// Store current Node in Map
map.put(M.getNid(), M);
}
public void map(Object key, Text value, Context context)
throws IOException, InterruptedException {
NodeWritable n = new NodeWritable(value.toString().trim());
// Emit node to carry forward the Model.
NodeWritable p = new NodeWritable(value.toString().trim());
p.setIsNode(new Text("YES"));
p.setIsInList(new Text("***"));
context.write(new Text(p.getNid().toString()), p);
// For Each OutLinks Emit This Node
for (NodeWritable x : n.getOuts()) {
if (!x.getNid().toString().equals(n.getNid().toString())) {
n.setIsInList(new Text("YES"));
n.setIsNode(new Text("NO"));
context.write(new Text(x.getNid().toString()), n);
}
}
// For Each Inlinks Emit This Node
for (NodeWritable x : n.getIns()) {
if (!x.getNid().toString().equals(n.getNid().toString())) {
n.setIsInList(new Text("NO"));
n.setIsNode(new Text("NO"));
context.write(new Text(x.getNid().toString()), n);
}
}
}
