error when using gpu

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Mate 2u
Mate 2u on 21 May 2012
Hi this is the part of code which troubles me:
for j=1:length(ZZ)
array(:,index) = A(ZZ(j)+n:ZZ(j)+n+x-1);
The error I get is:
Undefined function 'colon' for input arguments of type 'parallel.gpu.GPUArray'.
Any help?

Accepted Answer

Ben Tordoff
Ben Tordoff on 24 May 2012
Unfortunately, an expression like:
won't work, and (as Walter says) it looks like one of your ":" expressions involves an argument that is a gpuArray. You have two choices. If you want the result of the ":" to be on the GPU you have to say so explicitly:
tmp = parallel.gpu.GPUArray.colon(ZZ(j)+n, ZZ(j)+n+x-1);
array(:,index) = A(tmp);
If you prefer the result in host memory, gather it first:
tmp = colon(gather(ZZ(j)+n), gather(ZZ(j)+n+x-1));
array(:,index) = A(tmp);
The result should be the same either way, but you may find one faster than the other depending on your data size, hardware and MATLAB release.

More Answers (1)

Walter Roberson
Walter Roberson on 21 May 2012
This implies that ZZ or n are located on the GPU, with the result that ZZ(j)+n is a GPU object. The ":" operator cannot deal with GPU objects.


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