// 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 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());
}
}
