1967
Comment:

1981

Deletions are marked like this.  Additions are marked like this. 
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double pi = 0.0; int numPeers = bspPeer.getNumCurrentMessages(); BSPMessage received; while ((received = bspPeer.getCurrentMessage()) != null) { pi += Bytes.toDouble(received.getData()); } 

Line 58:  Line 52: 
double pi = 0.0; int numPeers = bspPeer.getNumCurrentMessages(); BSPMessage received; while ((received = bspPeer.getCurrentMessage()) != null) { pi += Bytes.toDouble(received.getData()); } 
Pi Estimator
The value of PI can be calculated in a number of ways. In this example, we are estimating PI using following way:
 Each task executes locally its portion of the loop a number of times.
iterations = 10000 circle_count = 0 do j = 1,iterations generate 2 random numbers between 0 and 1 xcoordinate = random1 ycoordinate = random2 if (xcoordinate, ycoordinate) inside circle then circle_count = circle_count + 1 end do PI = 4.0*circle_count/iterations
 One task acts as master and collects the results through the BSP communication interface.
PI = pi_sum / n_processes
1) Each process computes the value of Pi locally, and 2) sends it to master task using send() function. Then, 3) the master task can recieve the messages using sync() function. Finally, we can calculate the average value of sum of PI values from each peers as below:
public void bsp(BSPPeerProtocol bspPeer) throws IOException, KeeperException, InterruptedException { int in = 0, out = 0; for (int i = 0; i < iterations; i++) { double x = 2.0 * Math.random()  1.0, y = 2.0 * Math.random()  1.0; if ((Math.sqrt(x * x + y * y) < 1.0)) { in++; } else { out++; } } byte[] tagName = Bytes.toBytes(bspPeer.getPeerName()); byte[] myData = Bytes.toBytes(4.0 * (double) in / (double) iterations); BSPMessage estimate = new BSPMessage(tagName, myData); bspPeer.send(masterTask, estimate); bspPeer.sync(); if (bspPeer.getPeerName().equals(masterTask)) { double pi = 0.0; int numPeers = bspPeer.getNumCurrentMessages(); BSPMessage received; while ((received = bspPeer.getCurrentMessage()) != null) { pi += Bytes.toDouble(received.getData()); } pi = pi / numPeers; writeResult(pi); } }