Detect matlab processes from within matlab

If you're on Windows, you could do this:

[s,w] = dos( 'tasklist' );
numMatlabs = length( regexp( w, '(^|\n)MATLAB.exe' ) )

Here's another approach: you could use Matlab's COM "Automation Server" to start up workers and control them from a central Matlab process.

function out = start_workers(n)
myDir = pwd;
for i=1:n
    out{i} = actxserver( 'matlab.application.single' );
    out{i}.Execute(sprintf('cd(''%s'')', myDir));
end

Then you can use Execute() to have them run work. You could use a timer trick to get sort of asynchronous execution.

function out = evalasync(str)
%EVALASYNC Asynchronous version of eval (kind of)
%
% evalasync(str)  % evals code in str
% evalasync()     % gets results of previous call

persistent results status exception

if nargin == 0
    out = {status results exception}; % GetWorkspaceData doesn't like structs
    assignin('base', 'EVALASYNC_RESULTS', out); % HACK for Automation
    return
end

status = 'waiting';
    function wrapper(varargin)
        status = 'running';
        try
            results = eval(str);
            status = 'ok';
        catch err
            status = 'error';
            exception = err;
        end
    end

t = timer('Tag','evalasync', 'TimerFcn',@wrapper);
startat(t, now + (.2 / (60*60*24)));

end

Then

w = start_workers(3);
w{1}.Execute('evalasync(''my_workload(1)'')');
w{2}.Execute('evalasync(''my_workload(2)'')');

Unfortunately, you're stuck with single-threading in the workers, so if you call evalasync() again to check the results, it'll block. So you'd want to monitor their progress through files on disk. So it may not be much of a win.

on linux

!ps -ef |grep "/usr/local/matlab78/bin/glnxa64/MATLAB"|wc -l

would do the trick (replace path by your own and subtract 1 for the grep process)

(or to build in to a function, use

[tmp, result] = system('ps -ef |grep "/usr/local/matlab78/bin/glnxa64/MATLAB"|wc -l');
str2double(result) - 1

also, you can use

>>computer
ans = GLNXA64

to find out which system architecture (win/linux/etc ) a program is currently executing on