parfor using
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Hi everybody, i have a question about parfor using. I tried a classical example for parfor on my PC but i couldn't get gainly results. How ?
nmax=1000;
y = zeros(nmax,1);
tic
parfor n = 1:nmax
z = randn(n);
y(n) = max(svd(z));
end
toc
Results:
(nmax, pool size, time)
(500, 0, 12.51) (500, 2, 8.71) (500, 4, 5.16) That's OK.
(750, 0, 46.03) (750, 2, 38.65) (750, 4, 30.32) Maybe OK.
(1000, 0, 141.40) (1000, 2, 156.19) (1000, 4, 174.81) Why ?
Thanks for replies.
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Respuesta aceptada
Laurens Bakker
el 7 de Mzo. de 2012
Hi Yildirim,
There is considerable overhead in gathering the data back into a single variable. I removed the assignments and that improves the situation.
nmax=1000;
y = zeros(nmax,1);
tic
parfor n = 1:nmax
max( svd( randn(n) ));
end
toc
Cheers,
Laurens
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