Octave parallel execution package for cluster computers

Description

 This is a package to add parallel computing functions to Octave. The
parallel computing functions are supported without any additional
parallel computing libraries such as MPI and PVM.  The operation has
been confirmed only on Linux (but it may be applicable to other
operating systems).



Requirements

 1. GNU Octave 2.1.43 that is available at http://www.octave.org/
 2. two or more computers



How to use
 Note first that this package assumes the use in a multiple-computer 
 system consisting of a master (your console) computer and some 
 slave computers.  Run Octave with argument "server.m" on every slave 
 computer.

 $ octave /usr/local/share/octave/2.1.43/site/m/octave-forge/parallel/server.m

 Run Octave without argument "server.m" on the master computer

 $ octave -q -f script.m 
  or
 $ octave

 > script



Command references

connect (hosts) 
 Make bi-directional connections among the computers specified by 
 the matrix "hosts" and return the matrix of the sockets (file 
 descriptors) directed to the listed computers.
 This command should be executed on the master computer before 
 starting parallel computation. For example, 
 you can execute the following command on the master computer:
        connect ([ "host1"; "host2"; "host3" ])
                => [ 0, 0; 5, 3; 6, 4 ]
 where host1, host2 and host3 are the host names (or IP addresses).  
 In a typical situation, host1 is the master, and host2 and host3 
 are the slave computers.  A pair of socket numbers (e.g., "5, 3")
 is assigned to each host.  As a side effect, this command automatically 
 issues the connect commands at the slave computers host2 and host3 
 in order to establish the connection from each slave computer 
 (host2 or host3) to the other master/slave computers.  Note that
 the return value of the connect command automatically executed 
 on each slave computer is stored in the variable "sockets".  The
 slave computer can refer this variable to send/receive data to/from
 other computers.  As a result, the bi-directional complete connection
 among the listed computers is established.


send (x, sockets)
 Send the variable "x" to the computers specified by matrix "sockets".
 For example,

        send ([ 1+2i, 3; 4, 5+6i ],sockets(2:3,:));

 The variable can be any Octave data type.

recv (socket)
 Receive a variable from the computer specified by the row vector "socket". 
 For example,

        recv (sockets(1,:))
           => [ 1+2i, 3; 4, 5+6i ]

reval (commands, sockets)
 Evaluate "commands" at the remote hosts specified by the matrix "sockets".
 For example,

        reval ([ "a=[ 1:3 ]"; "a=a'*a" ],socket(2,:));

sclose (sockets)
 Close the connections specified by the matrix "sockets".
 Returns zero on success, or nonzero if an error occurred.
 For example,

        sclose (sockets);



Notes for the current version:
* The slave computer must have the directory whose name and path are 
  identical with the current directory of the master computer.


Sample program:
 The following Octave script calculates the sum of the integers 
 from 1 to 100.  The computation is divided into half and assigned 
 to "host2" and "host3".

clear;
hosts = [ "host1"; "host2"; "host3" ];
sockets = connect(hosts);
psum = zeros(1,2);
reval( "send(sum([1:50]),sockets(1,:))", sockets(2,:));
reval( "send(sum([51:100]),sockets(1,:))", sockets(3,:));
psum(1) = recv(sockets(2,:));
psum(2) = recv(sockets(3,:));
sum(psum)
scloseall(sockets);


 In the following script, the variable s="Hello, again!" 
 passes through 4 computers.

clear;
hosts = [ "host1"; "host2"; "host3"; "host4" ]; 
sockets = connect(hosts);
s="Hello, again!";
send(s,sockets(2,:));
reval( "s=recv(sockets(1,:));",sockets(2,:));
reval( "send(s,sockets(3,:));",sockets(2,:));
reval( "s=recv(sockets(2,:));",sockets(3,:));
reval( "send(s,sockets(4,:));",sockets(3,:));
reval( "s=recv(sockets(3,:));",sockets(4,:));
reval( "send(s,sockets(1,:));",sockets(4,:));
s2=recv(sockets(4,:))
scloseall(sockets);



License:
 This package is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2, or (at your option)
 any later version.



Comments and suggestions should be directed to: 
 h_fujiwara@users.sourceforge.net