MATLAB: Fprintf output in a parallel computing job

jobMATLABParallel Computing Toolbox

Hi,

If I use disp or fprintf in a function called as a task in a parallel computing job, where does the output end up? It does not appear in the desktop window. Is it written to a file somewhere, or is it discarded completely?

Thanks in advance, Paul

Best Answer

If you use the batch function to submit a job, you can use the "diary" method on the job to see the output. For example

    j = batch( 'disp hello' ); % submit a simple command
    wait(j), diary(j) % display the output

If you use the jobs and tasks API directly, you need to set the "CaptureCommandWindowOutput"/"CaptureDiary" flag to true before submission, and check the "CommandWindowOutput"/"Diary" property after execution. (The first option is for R2011b and before, the second for the new API in R2012a).

Related Solutions

MATLAB: How to take advantage of useParallel option for a remote job running on workers in a MDCS cluster

1. In order to use parallel pool with the cluster, please consider using the 'batch' function procedure to submit the jobs into cluster:

https://www.mathworks.com/help/distcomp/batch.html

When using the 'batch' command, it has the option to specify the number of workers to be used in addition to the job itself. Please refer to the example below:

c=parcluster('profile');
j = batch(c,@scriptUseParallel, 'Pool', 2);
wait(j);
diary(j);
Y2=fetchOutputs(j);

2. In the cluster setup, please consider to configure each machine to have the same number of workers as the number of cores.

Therefore each core can be started with a MATLAB process and being utilized by the batch job.

MATLAB: How to use Task.Diary

The task "diary" property is updated automatically when your task function would emit text to the command window. For example:

   c = parcluster('local');
   j = createJob(c);
   t = createTask(j, @disp, 0, {magic(4)}, 'CaptureDiary', true);
   submit(j);
   wait(j);
   t.Diary

Best Answer

Related Solutions

MATLAB: How to take advantage of useParallel option for a remote job running on workers in a MDCS cluster

MATLAB: How to use Task.Diary

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