MATLAB: The parallel pool that SPMD was using has been shut down.

MATLABParallel Computing Toolboxspmd parallel computing toolbox gpu

Hi, I want to use parallel GPU-Computing for MatConvNet (code for multiple GPUs already exists). But I get a Matlab error in the Parallel Computing Toolbox.
At the command SPMD this error occurcs: "The parallel pool that SPMD was using has been shut down."
Code from MatConvNet:
function prepareGPUs(opts, cold)
numGpus = numel(opts.gpus) ;
if numGpus > 1
    % check parallel pool integrity as it could have timed out
    pool = gcp('nocreate') ;
    if ~isempty(pool) && pool.NumWorkers ~= numGpus
      delete(pool) ;
    end
    pool = gcp('nocreate') ;
    if isempty(pool)
      parpool('local', numGpus) ;
      cold = true ;
    end
end
if numGpus >= 1 && cold
    fprintf('%s: resetting GPU\n', mfilename)
    clearMex() ;
    if numGpus == 1
      gpuDevice(opts.gpus)
    else
      spmd
        clearMex() ;
        gpuDevice(opts.gpus(labindex))
      end
    end
end
That is why I try to test the parallel toolbox itself and get the same error. See attached image…
A out of ERROR-LOG-FILE (complete Log-FILE in the appendix)
 job aborted:
 rank: node: exit code[: error message]
 0: 127.0.0.1: -2
 1: 127.0.0.1: 0: process 1 exited without calling finalize
 2: 127.0.0.1: -2
 3: 127.0.0.1: -2
I am using Ubuntu 14.4 and 4 TITAN Xp
Any ideas, what I can do? Thanks for help! Regards, André

Best Answer

Hello. Andre. I encounter the same problem last day. The reason is that I have the same name function in my matlab environment which the warning is the function xxx has the same name in matlab builtin functions. so it can't use the parallel tool. so I changed the search path and make sure there is only one function use in matlab, finally it works. May this help you.
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