MATLAB Answers

For indexing in gpuArray, how can I improve my code?

1 view (last 30 days)
zihao chang
zihao chang on 16 Mar 2021
Edited: Joss Knight on 18 Mar 2021
function dists = compute_distances(obj,X)%X is a matrix with 10000 X 1024
num_test=size(X, 1);
num_train=size(obj.x_train,1);
temp_dists=double(zeros(num_test,num_train));
gpu_X=gpuArray(X);
gpu_xtrain=gpuArray(obj.x_train);%obj.x_train is a matrix with 1000 X 1024
for i = 1:num_test
for j =1:num_train
tmp=X(i,:)-obj.x_train(j,:);
temp_dists(i,j)=sqrt(sum(tmp.*tmp));
end
end
dists=temp_dists;
end
My CPU code executed in 5 mins.
The GPU code executed in 25mins.
I am trying to calculate the distance, but I noticed that I can use gpuArray to improve the speed.
I have no idea why it doesn't work.

Accepted Answer

Joss Knight
Joss Knight on 18 Mar 2021
Edited: Joss Knight on 18 Mar 2021
Firstly, use pdist2.
Secondly, say no to loops:
Y = reshape(obj.x_train',1,[],num_train);
delta = X-Y;
dists = squeeze(sqrt(sum(delta.*delta,2)));

More Answers (0)

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by