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Old 2010-09-21, 07:05   #107
A Sunny Moo
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Aug 2007

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Originally Posted by Brucifer View Post
yeah, it would be interesting then cause I've got 9 gpu's that it would be interesting to try doing a sieving run on. They should really speed up the process from what it was like when I was doing a bunch of sieving before on quads. Used to take a ton of time.

So it would be a kick to give stuff a dry run on some already been sieved stuff to see what the comparison is like for speed and accuracy. I've got a trip starting up in another day but will be back next week and it would be a interesting to pursue this if you are game. Just possible that we might be able to really knock out some serious sieving!!!!!

Edit: but I would also like to try out some llr tests if that is at all possible............... heh heh heh
Currently NPLB has no active team sieves, but in light of the currently available GPU sieving options, Gary and I have discussed starting our next big sieve, k=400-1001, n=1M-2M, sooner rather than later.

ppsieve-CUDA is already well enough tested that only minimal time needs to be spent on a "dry run" to ensure everything is working properly before jumping into real work. You can download ppsieve-CUDA and find information on how to do a quick test here. If that produces the expected factors then you should be good.

For ppsieve-OpenCL, development has proceeded at least far enough that it can be confidently expected to produce good factors; see here to download it and run a self-test as before with CUDA. The main thing that's left to be done now is to further tweak the program to optimize it better for speed. But it should still be decently fast as is.

With GPUs now so readily usable for sieving, we may actually want to consider using a GPU to calculate the optimal depth for future NPLB sieves. That is, sieve until the removal rate on a GPU is equal to the time it takes to do an equivalent LLR test. We'd be spending just about as much wall-clock time sieving, but we'd have a much higher final depth and a much better sieved final file. Kind of like how we used to calculate optimal depth based on 32-bit sieving, but now use 64-bit.

Last fiddled with by mdettweiler on 2010-09-21 at 07:07
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