PrimeGrid
Please visit donation page to help the project cover running costs for this month

Toggle Menu

Join PrimeGrid

Returning Participants

Community

Leader Boards

Results

Other

drummers-lowrise

Advanced search

Message boards : Proth Prime Search : Smaller FFT size, longer CPU time

Author Message
Profile BurProject donor
Volunteer tester
Avatar
Send message
Joined: 25 Feb 20
Posts: 462
ID: 1241833
Credit: 279,927,511
RAC: 549,978
321 LLR Ruby: Earned 2,000,000 credits (2,092,823)Cullen LLR Ruby: Earned 2,000,000 credits (2,002,841)ESP LLR Amethyst: Earned 1,000,000 credits (1,445,099)Generalized Cullen/Woodall LLR Ruby: Earned 2,000,000 credits (2,180,764)PPS LLR Amethyst: Earned 1,000,000 credits (1,225,852)PSP LLR Ruby: Earned 2,000,000 credits (2,064,832)SoB LLR Amethyst: Earned 1,000,000 credits (1,669,219)SR5 LLR Ruby: Earned 2,000,000 credits (2,065,004)SGS LLR Amethyst: Earned 1,000,000 credits (1,202,156)TRP LLR Ruby: Earned 2,000,000 credits (2,089,856)Woodall LLR Ruby: Earned 2,000,000 credits (2,112,258)321 Sieve (suspended) Ruby: Earned 2,000,000 credits (2,107,153)PPS Sieve Turquoise: Earned 5,000,000 credits (5,080,097)AP 26/27 Ruby: Earned 2,000,000 credits (4,685,837)GFN Turquoise: Earned 5,000,000 credits (7,489,336)WW Double Silver: Earned 200,000,000 credits (239,400,000)PSA Amethyst: Earned 1,000,000 credits (1,022,470)
Message 145337 - Posted: 18 Nov 2020 | 18:28:53 UTC
Last modified: 18 Nov 2020 | 18:30:51 UTC

While browsing PPS Mega tasks, I saw that some took 4100 s, some 5400 s. I assumed the latter had the larger FFT size and larger k, but not so.

The 4100 s tasks had FFT = 256k, the 5400 s ones had FFT = 240k.

Here are examples of each: 4100 s and 5400 s or the whole list here.

The difference seems to be the pass1 and pass2, in one case pass1 is larger, in the other pass2 is larger. And a is either 3 or 5.

What do these parameters mean and how do they influence the CPU time in such a way that smaller FFT size means longer CPU time? Especially since the tasks with shorter run times had the larger k and accordingly larger FFT.
____________
1281979 * 2^485014 + 1 is prime ... no further hits up to: n = 4,800,000

Profile Eudy SilvaProject donor
Avatar
Send message
Joined: 26 Aug 17
Posts: 1540
ID: 918937
Credit: 341,502,558
RAC: 184,770
Discovered 2 mega primesFound 2 primes in the 2018 Tour de PrimesFound 1 prime in the 2019 Tour de PrimesFound 1 prime in the 2020 Tour de PrimesFound 1 prime in the 2021 Tour de Primes321 LLR Amethyst: Earned 1,000,000 credits (1,012,503)Cullen LLR Amethyst: Earned 1,000,000 credits (1,291,013)ESP LLR Amethyst: Earned 1,000,000 credits (1,151,976)Generalized Cullen/Woodall LLR Amethyst: Earned 1,000,000 credits (1,004,746)PPS LLR Jade: Earned 10,000,000 credits (19,941,997)PSP LLR Amethyst: Earned 1,000,000 credits (1,476,639)SoB LLR Ruby: Earned 2,000,000 credits (2,432,091)SR5 LLR Ruby: Earned 2,000,000 credits (2,954,518)SGS LLR Amethyst: Earned 1,000,000 credits (1,462,951)TRP LLR Amethyst: Earned 1,000,000 credits (1,574,163)Woodall LLR Amethyst: Earned 1,000,000 credits (1,001,901)321 Sieve (suspended) Amethyst: Earned 1,000,000 credits (1,119,749)Generalized Cullen/Woodall Sieve (suspended) Amethyst: Earned 1,000,000 credits (1,005,331)PPS Sieve Emerald: Earned 50,000,000 credits (68,690,867)AP 26/27 Emerald: Earned 50,000,000 credits (50,096,813)GFN Emerald: Earned 50,000,000 credits (79,214,681)WW Double Bronze: Earned 100,000,000 credits (104,012,000)PSA Ruby: Earned 2,000,000 credits (2,059,222)
Message 145348 - Posted: 18 Nov 2020 | 20:25:28 UTC - in response to Message 145337.

There was some talking about this last year:
https://www.primegrid.com/forum_thread.php?id=8628&nowrap=true
____________
"Accidit in puncto, quod non contingit in anno."
Something that does not occur in a year may, perchance, happen in a moment.

Profile BurProject donor
Volunteer tester
Avatar
Send message
Joined: 25 Feb 20
Posts: 462
ID: 1241833
Credit: 279,927,511
RAC: 549,978
321 LLR Ruby: Earned 2,000,000 credits (2,092,823)Cullen LLR Ruby: Earned 2,000,000 credits (2,002,841)ESP LLR Amethyst: Earned 1,000,000 credits (1,445,099)Generalized Cullen/Woodall LLR Ruby: Earned 2,000,000 credits (2,180,764)PPS LLR Amethyst: Earned 1,000,000 credits (1,225,852)PSP LLR Ruby: Earned 2,000,000 credits (2,064,832)SoB LLR Amethyst: Earned 1,000,000 credits (1,669,219)SR5 LLR Ruby: Earned 2,000,000 credits (2,065,004)SGS LLR Amethyst: Earned 1,000,000 credits (1,202,156)TRP LLR Ruby: Earned 2,000,000 credits (2,089,856)Woodall LLR Ruby: Earned 2,000,000 credits (2,112,258)321 Sieve (suspended) Ruby: Earned 2,000,000 credits (2,107,153)PPS Sieve Turquoise: Earned 5,000,000 credits (5,080,097)AP 26/27 Ruby: Earned 2,000,000 credits (4,685,837)GFN Turquoise: Earned 5,000,000 credits (7,489,336)WW Double Silver: Earned 200,000,000 credits (239,400,000)PSA Amethyst: Earned 1,000,000 credits (1,022,470)
Message 145388 - Posted: 19 Nov 2020 | 17:34:11 UTC - in response to Message 145348.

Ok, thanks I will continue in that thread.
____________
1281979 * 2^485014 + 1 is prime ... no further hits up to: n = 4,800,000

Post to thread

Message boards : Proth Prime Search : Smaller FFT size, longer CPU time

[Return to PrimeGrid main page]
DNS Powered by DNSEXIT.COM
Copyright © 2005 - 2021 Rytis Slatkevičius (contact) and PrimeGrid community. Server load 1.93, 1.88, 1.82
Generated 21 Sep 2021 | 19:40:06 UTC