Using the GPU for parallel computing in Matlab

Question

I've reached a stage where my arrays have become massive and a single function takes about 2 days to compute.

I am working with image processing and using kmeans and gmm - fitgmdist.

I have a workstation with Nvidia Tesla GPU's which are on the supported list and I would like to use their processing power to help speed up my work.

Looking into the documentation, I understand that in order to use the GPU functions all I have to do is to pass the array that is being passed to the functions to the GPU first. i.e.

model_feats = get_feats(all_imges);
kmeans = kmeans(model_feats, gaussians, 'EmptyAction','singleton', 'MaxIter',1000);
gmm{i} = fitgmdist(model_feats, 128, 'Options',statset('MaxIter',1000), ...
            'CovType','diagonal', 'SharedCov',false, 'Regularize',0.01, 'Start',cInd);

All of my processing time is taken up by these two functions. So if I am to use the GPU cores, is all that I have to do is use the gpuArray function? For example the above will become:

temp_feats = get_feats(all_imges);
model_feats = gpuArray(temp_feats);

kmeans = kmeans(model_feats, gaussians, 'EmptyAction','singleton', 'MaxIter',1000);
gmm{i} = fitgmdist(model_feats, 128, 'Options',statset('MaxIter',1000), ...
            'CovType','diagonal', 'SharedCov',false, 'Regularize',0.01, 'Start',cInd);

Will this work? Will it work for any function by first passing the array to gpuArray?

P.S. Sorry I have to ask here rather than just try it myself, but I do not have access to the workstation as of now, but I can request access to it. Before I request access to it I wanted to make sure if my script will work with gpuArray.

Answer 1

Unfortunately, in short the answer to your question is No, it wont work.

The matlab GPU support is all but partial. The currently supported functions which accepts gpuArray inputs are given in: http://de.mathworks.com/help/distcomp/run-built-in-functions-on-a-gpu.html

So in my understanding, since kmeans is not in the list, it should not work. Someone please correct me if I'm wrong.

But on the other hand, if you do a google search, you can see 3rd party matlab implementations of kmeans on GPUs. Since I cant grantee the quality of the code, I wouldn't be posting a link.

Good luck!