20180122, 09:07  #353 
May 2004
FRANCE
1000101101_{2} Posts 
Verfying a Genealized Fermat prime
Hi,
I verified the primality of the last prime announced on the Prime Database Verification Status, using llrCUDA V3.8.1 : ./llrCUDA d a7 oVerbose=1 oDebug=0 q"1880370^524288+1" [Sat Jan 20 18:55:48 2018] Base factorized as : 2*3^2*5*17*1229 Base prime factor(s) taken : 17, 1229 Starting N1 prime test of 1880370^524288+1 Using complex rational base DWT and generic reduction, FFT length = 1507328, a = 3 [Mon Jan 22 06:51:05 2018] 3^((N1)/1229)1 is coprime to N! [Mon Jan 22 08:40:50 2018] 3^((N1)/17)1 is coprime to N! 1880370^524288+1 is prime! (3289511 decimal digits) Time : 123098.306 sec. The total time is pretty satisfying, but gcd's calculus by giants code took several hours... I have to write a CUDA gcd code! Regards, Jean 
20180122, 09:51  #354  
Dec 2011
After milion nines:)
1285_{10} Posts 
Quote:
34 hours is OK time :) 

20180122, 12:45  #355 
May 2004
FRANCE
557 Posts 

20180924, 09:03  #356 
Feb 2011
2^{2}×5 Posts 
Anybody got a Windows binary?
Willing to try RTX 2080 and how it is doing... 
20181129, 18:19  #357 
"Curtis"
Feb 2005
Riverside, CA
11×383 Posts 
I have llrcuda running on ubuntu 16.04, SBera Xeon with Quadro 5000 GPU.
When testing with k=443 and exponents around 3.3M, the FFT chosen is about 4 times larger than regular sllr64 (917nnn vs 224k). I tried another exponent just over 6M, and again FFT is roughly 4x larger (~1.5M vs 400k). llrcuda uses 100% load on one core, 90+% on GPU, but production is marginally worse than using that one CPU core for sllr64 alone. If FFT size choice is a bug and can be fixed, it appears my GPU could do work at the rate of 34 cores of this system, which would be quite nice! Previous versions have shown better speed with smaller k; I'll next try k=13 and report any improvement. 
20181129, 19:03  #358  
"Robert Gerbicz"
Oct 2005
Hungary
29×47 Posts 
Quote:
gcd(c0,n)=1 && gcd(c1,n)=1 ... gcd(c_t,n)=1 is true iff gcd(r,n)=1, where r=(c0*c1*c2*...*c_t)%n so in every case where you'd use the Generalized Pocklington theorem it is enough to compute only one gcd. Last fiddled with by R. Gerbicz on 20181129 at 19:04 

20181129, 19:57  #359  
Sep 2006
The Netherlands
1010100010_{2} Posts 
VB Curtis i'm carefully watching your findings.
The Xeon i do not know how many gflops a single core is on paper double precision, yet if it's a Fermi Quadro 500 GPU it's having 359.04 gflops double precision and 120GB/s bandwidth to the GDDR5 with 152 watt TDP  but that last number is just a Coca Cola Toto number. What Ghz setting does the Xeon have? For now blindfolded guess the SB is single core factor 20 slower than the Quadro... Quote:
Last fiddled with by diep on 20181129 at 19:59 

20181129, 20:20  #360 
"Curtis"
Feb 2005
Riverside, CA
11·383 Posts 

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