edu.rit.clu.antimatter

Class AntiprotonClu3

java.lang.Object

edu.rit.clu.antimatter.AntiprotonClu3

public class AntiprotonClu3
extends java.lang.Object

Class AntiprotonClu3 is a cluster parallel program that calculates the positions of the antiprotons as a function of time. Each antiproton experiences a net repulsive force from all the other antiprotons. Each antiproton also experiences a force due to a magnetic field perpendicular to the plane in which the antiprotons move.

Usage: java -Dpj.np=K edu.rit.clu.antimatter.AntiprotonClu3 seed R dt steps snaps N outfile

The program runs in K parallel processes. Each process writes its own output file. If outfile is specified as "out.dat", for example, then process 0 writes file "out_0.dat", process 1 writes file "out_1.dat", and so on.

The program:

1. Initializes a pseudorandom number generator with seed.
2. Generates N antiprotons positioned at random in the square from (0.25R,0.25R) to (0.75R,0.75R).
3. Sets each antiproton's initial velocity to 0.
4. Stores a snapshot of the antiprotons' initial positions in the outfile.
5. Performs steps time steps and stores another snapshot of the antiprotons' positions in the outfile. Each time step is dt.
6. Repeats Step 5 snaps times. The number of snapshots stored in the outfile is snaps+1.

The computation is performed in parallel in multiple processors. The program measures the computation's running time.

Each process holds one slice of the position array, one slice of the velocity array, and one slice of the acceleration array. At each time step, each process calculates its own slice of the acceleration array; the slices of the position array are passed from process to process in a pipelined fashion; the communication is overlapped with the computation of the acceleration array. After all position array slices have passed through all processes, each process uses its slice of the acceleration array to update its slices of the velocity and position arrays. Each process writes snapshots of its own slice of the position array into the process's own output file.

Method Summary

Modifier and Type	Method and Description
static void	main(java.lang.String[] args) Main program.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception

Main program.

Throws:

java.lang.Exception