Matlab automatically work with multiple graphic cards?

I have installed two units of GE Force Titan. How can I check whether MATLAB is properly allocating jobs to two GPU?

Answer 1

[Joss Knight]

To make use of both GPUs in parallel, open a parallel pool with two workers:

parpool('local', 2);

Use gpuDevice to show you which card each lab is using:

spmd
  gpuDevice
end

You will find your labs distributed evenly between the GPUs. You can reassign the workers to whichever GPU you like by passing an index to gpuDevice, for instance:

spmd
  gpuDevice(labindex)
end

Answer 2

[Walter Roberson]

I am usually a bit behind in tracking changes to the Parallel Computing Toolbox, so it is possible there has been enhancements that I have not noticed yet.

Last I saw, any one worker could only be associated with a single GPU, but in some circumstances, multiple workers could be associated with the same GPU. Thus MATLAB would not automatically allocate jobs to "available" GPUs, but a worker can request that it be associated with a specific GPU.