Class Jacobi

java.lang.Object
  |
  +--Task
        |
        +--Jacobi

All Implemented Interfaces:

net.jini.core.entry.Entry, java.io.Serializable

public final class Jacobi

extends Task

This class demonstrates the use of JavaSpaces to solve iterative problems on a regular grid/mesh. Because of the generally high communication needs of such problems -- and other issues outlined below -- more than anything else this code shows that JavaSpaces is probably not a good technology choice for iterative grid solvers. Even if we used known better algorithms (like red-black SOR, instead of simple Jacobi relaxation) the communication cost of using JavaSpaces would still be too great. Note, too, the additional hoops through which one must jump to squeeze out as much performance as possible: - using snapshots to retrieve from left/right neighbors - shadowing the primitive Object wrappers with local primitive variables (to avoid object reference checks when looping) - shadowing 2D array contents in 1D arrays, to save 2D array reference costs As such this code is considerably more complex than the corresponding C implementation of SOR given within the cbench directory.

Author:

Michael S. Noble (mnoble@cfa.harvard.edu) Copyright (c) 2000 This code may only be used under the terms of GNU General Public License.

See Also:

Serialized Form

Field Summary

java.lang.Integer	N
java.lang.Integer	P
net.jini.space.JavaSpace	space
java.lang.Double	tolerance

Fields inherited from class Task

data, done, id, result

Constructor Summary

Jacobi()

Jacobi(long workerID, int P, int N, double tolerance, net.jini.space.JavaSpace space)

Method Summary

java.lang.Object	compute()
java.lang.Object	mergeResult(java.lang.Object meshArray)
java.lang.String	name()
void	reportResult(java.lang.Object result)

Methods inherited from class Task

execute, finalize, keepData

Methods inherited from class java.lang.Object

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

Field Detail

P

public java.lang.Integer P

N

public java.lang.Integer N

tolerance

public java.lang.Double tolerance

space

public net.jini.space.JavaSpace space

Constructor Detail

Jacobi

public Jacobi()

Jacobi

public Jacobi(long workerID,
              int P,
              int N,
              double tolerance,
              net.jini.space.JavaSpace space)

Method Detail

compute

public java.lang.Object compute()

Overrides:

compute in class Task

name

public java.lang.String name()

Overrides:

name in class Task

mergeResult

public java.lang.Object mergeResult(java.lang.Object meshArray)

Overrides:

mergeResult in class Task

reportResult

public void reportResult(java.lang.Object result)

Overrides:

reportResult in class Task