My msieve cuda setup as a newbie

[prss]

Right jasonp, but how i choose A and B for spend less time in search?
Has some formula to choose A and B in function of N ?

[jasonp]

Not really; all the guidance on choosing the range is pretty anecdotal.

A small range finishes quickly, and small A and B find polynomials that are very highly skewed, which maximizes the search space for stage 2 to find a good polynomial. If you only have a little time to search, A=1 is a good idea; but the best polynomials have very good size and very good root properties, whereas limiting the A-B range to small values will find excellent root properties but will not do much to find a polynomial with good size.

Polynomial selection is a process where the only way to find the best results is to spend a lot of time looking. Since we often do not have a lot of time, there is a tradeoff we all have to make based on how long the sieving will take and how good the results found so far have been. If you have an Amazon compute farm ready to do the sieving you do not need a perfect polynomial, and if you are factoring very large integers you can spend weeks looking for a polynomial.

[Dubslow]

Originally Posted by prss

Right jasonp, but how i choose A and B for spend less time in search?
Has some formula to choose A and B in function of N ?

If you have the answer, you should definitely consider publishing it in a peer reviewed journal. (Read: as jason implies, there is no real good answer. NFS is as much more so guess work, smoke and mirrors than a proper A to B algorithm.)

[prss]

As I'm not have a Amazon cluster with 64GB+ of memory, i might consider to sieving and execute linear algebra phase storing data in a SSD disk, solving matrix in parts?

[prss]

Originally Posted by jasonp:
Sort the lines in the file and run the root optimization part of stage 2 (with -npr) only on the lines of the .ms file whose last field is the smallest, maybe the smallest 100 or so entries.

By which term I need to order? The line have that format:
12 120274200 -1925450320035100 -15282382788549599 128117774098336313505596 64799414552419869488988 357477963239 -452243407311138901133651 -0.74 7.115460e+015

[Dubslow]

He said "last field", so 7.115460e+015.

[prss]

Sorry Dubslow, it was my lack of attention.
Thanks by clarifications.

I have the following GPU:

[ CUDA: GeForce GT 630M ]
 
Device Properties:
Device Name						GeForce GT 630M
PCI Domain / Bus / Device		0 / 1 / 0
Clock Rate						950 MHz
Asynchronous Engines			1
Multiprocessors / Cores			2 / 96
L2 Cache						128 KB
Max Threads Per Multiprocessor	1536
Max Threads Per Block			1024
Max Registers Per Block			32768
Max Instructions Per Kernel		512 million
Warp Size						32 threads
Max Block Size					1024 x 1024 x 64
Max Grid Size					65535 x 65535 x 65535

How many threads result in better speedup in polynomial selection using msieve?

[prss]

After of some tests i see that greater speedup happen when use number of threads equal to Warp Size (32 in my case).

My GPU with 96 cuda cores was 5x faster than core i5 2,5 Ghz.

[jasonp]

The number of CPU threads should have nothing to do with the size of a CUDA warp, and in fact the latest SVN limits the number of GPU stage 1 threads to 4.

To repeat, this all becomes a moot point when you are not solving very small problems. Once you start factoring 140+ digit integers, forget about the number of threads.

[cgy606]

I'm new to using msieve by itself (I use yafu). I would like to use msieve for polynomial selection. I run the following command on a C141:

echo "(134!-5)/2844729212424914765373584725399627828496565276362417868278840579676885183018079137082195" | msieve152.exe -g 0 -t 2 -v -np1

I am using a windows 10 machine with a nvidia graphics card and I keep getting the error: "The programs can't start because pthreadGC2.dll" is missing". Does anybody know how to fix this?

[xilman]

Originally Posted by cgy606

I'm new to using msieve by itself (I use yafu). I would like to use msieve for polynomial selection. I run the following command on a C141:

echo "(134!-5)/2844729212424914765373584725399627828496565276362417868278840579676885183018079137082195" | msieve152.exe -g 0 -t 2 -v -np1

I am using a windows 10 machine with a nvidia graphics card and I keep getting the error: "The programs can't start because pthreadGC2.dll" is missing". Does anybody know how to fix this?

Yes. Even though I don't do Windoze, I can read an error message.

You need to track down a copy of the file "pthreadGC2.dll" and install it in the correct place. I suggest that you follow this link, as I did, and examine the results.

https://duckduckgo.com/?t=ouk&q=pthreadGC2.dll&ia=web



(Though I prefer duckduckgo to Google for privacy reasons.)