MATLAB: How to detect how many instances of Matlab are currently running on the machine

system

In task manager you can see how many matlab.exe there are.

is it possible to tell this from inside a matlab function?

eg I have a m function runing, doing stuff, and every so often I ask, "how many instances of matlab are running?" If the number is less than 2 say, then I am able to call a bat file from system.m to open a new instance and run a new job.

I dont have any fancy toolboxes eg parallel computing etc thanks

Best Answer

You can call the "tasklist" (DOS) function with some arguments that will tell you how many are running on the system. You can then parse the return and get a count.

e.g.:

>> [status,result] = system('tasklist /FI "imagename eq matlab.exe" /fo table /nh')
status =
       0
result =
MATLAB.exe                    5132 Console                    1    359,184 K
MATLAB.exe                    6028 Console                    1    358,908 K

Related Solutions

MATLAB: Can compiled MATLAB standalone make use of MDCS

Since R2008b applications deployed using the MATLAB compiler can access a cluster running MATLAB Distributed Computing Server.

The documentation has information and examples: http://www.mathworks.com/help/toolbox/compiler/f12-999353.html#br2jauc-47, but a quick example might look like this

function my_compiled_app
    % Open a matlabpool on the cluster defined
    % by the 'my_cluster' configuration
    matlabpool('open', 4, 'my_cluster');
    % Run a parfor loop on the cluster
    parfor i = 1:10
       disp(i)
    end
    % Close the pool   
    matlabpool('close');
  end

Compile the application using mcc

 >> mcc -m my_compiled_app

And the run it - this should open a matlabpool on the cluster, and show the parfor running

 C:\Work> my_compiled_app.exe

MATLAB: How to avoid duplicate running of Matlab Standalone Exe Application

Hi,

you could use the DOS function tasklist:

[~,b] = system('tasklist /fi "Imagename eq DataValidation.exe"')

and post process the output. However simply renaming the application would workaround that check.

Maybe consider creating a /checking for a file in the output folder at startup of your application. So something like

If LOCK_FILE_EXIST
  ABORT_START_OF_APPLICATION
ELSE
 CREATE_LOCK_FILE
 NORMAL_START
 DELTE_LOCK_FILE_AT_THE_END

OR in the case you are familar with .NET you could use a global mutex like explained here. So porting this to MATLAB would give

mutex = System.Threading.Mutex(true,'{8F6F0AC4-B9A1-45fd-A8CF-72F04E6BDE8F}') 
if mutex.WaitOne(System.TimeSpan.Zero,true)
    disp('I can run')
    pause(10)
    mutex.ReleaseMutex();
else
    disp('only one at a time')
end

Run this code in two different MATLAB at the same time and you will see that it works.

Best Answer

Related Solutions

MATLAB: Can compiled MATLAB standalone make use of MDCS

MATLAB: How to avoid duplicate running of Matlab Standalone Exe Application

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