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Message boards : Sieving : fsievecl64.exe vs fpsieve-x86_64-linux

Author Message
walli
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Joined: 12 Jun 16
Posts: 8
ID: 449456
Credit: 5,228,201,530
RAC: 660,541
Found 3 primes in the 2020 Tour de Primes321 LLR Turquoise: Earned 5,000,000 credits (5,334,168)Cullen LLR Turquoise: Earned 5,000,000 credits (5,002,299)ESP LLR Amethyst: Earned 1,000,000 credits (1,841,104)Generalized Cullen/Woodall LLR Silver: Earned 100,000 credits (123,484)PPS LLR Turquoise: Earned 5,000,000 credits (9,586,291)SoB LLR Jade: Earned 10,000,000 credits (10,540,541)SR5 LLR Amethyst: Earned 1,000,000 credits (1,735,467)SGS LLR Amethyst: Earned 1,000,000 credits (1,169,227)TRP LLR Amethyst: Earned 1,000,000 credits (1,322,057)Woodall LLR Ruby: Earned 2,000,000 credits (2,144,294)321 Sieve Jade: Earned 10,000,000 credits (13,542,496)Generalized Cullen/Woodall Sieve (suspended) Sapphire: Earned 20,000,000 credits (20,612,684)PPS Sieve Emerald: Earned 50,000,000 credits (53,507,883)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Silver: Earned 100,000 credits (295,388)AP 26/27 Jade: Earned 10,000,000 credits (10,127,715)GFN Sapphire: Earned 20,000,000 credits (37,265,297)PSA Double Turquoise: Earned 5,000,000,000 credits (5,054,047,170)
Message 118985 - Posted: 24 Jun 2018 | 11:26:04 UTC

Hi,

I ran a short test on FPS (range 8844-8845G) with the CPU and GPU app, but my GPU returned more results:

fsievecl64.exe:
---------------
8844124870297 | 23288!-1
8844301414811 | 490811!+1
8844346130771 | 413493!+1
8844391565431 | 453319!-1
8844512918177 | 379163!-1
8844516749147 | 695243!+1
8844635693029 | 313352!+1
8844792669553 | 766503!+1
8844821508923 | 579427!-1
8844830308543 | 719502!+1
8844963952049 | 692143!+1

fpsieve-x86_64-linux:
---------------------
8844346130771 | 413493!+1
8844516749147 | 695243!+1
8844635693029 | 313352!+1
8844792669553 | 766503!+1
8844821508923 | 579427!-1
8844963952049 | 692143!+1

I'm not into the topic, so my question is: Is it ok that the CPU app "potentially" removes less candidates (and sometimes even 0) than the OpenCL app?

I ask because my CPU took about 3 hours for 1G whereas my GPU crunched a little under an hour for the same range.

JimBProject donor
Honorary cruncher
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Joined: 4 Aug 11
Posts: 912
ID: 107307
Credit: 974,074,244
RAC: 85,572
Discovered 1 mega prime321 LLR Ruby: Earned 2,000,000 credits (2,671,514)Cullen LLR Turquoise: Earned 5,000,000 credits (5,031,868)ESP LLR Turquoise: Earned 5,000,000 credits (5,064,082)Generalized Cullen/Woodall LLR Turquoise: Earned 5,000,000 credits (5,038,750)PPS LLR Turquoise: Earned 5,000,000 credits (5,000,220)PSP LLR Turquoise: Earned 5,000,000 credits (7,639,762)SoB LLR Sapphire: Earned 20,000,000 credits (42,604,648)SR5 LLR Jade: Earned 10,000,000 credits (11,829,173)SGS LLR Ruby: Earned 2,000,000 credits (2,070,105)TRP LLR Ruby: Earned 2,000,000 credits (2,291,092)Woodall LLR Turquoise: Earned 5,000,000 credits (5,046,412)321 Sieve Jade: Earned 10,000,000 credits (10,032,608)Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (4,002,919)Generalized Cullen/Woodall Sieve (suspended) Sapphire: Earned 20,000,000 credits (20,005,451)PPS Sieve Emerald: Earned 50,000,000 credits (52,042,965)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Ruby: Earned 2,000,000 credits (2,341,676)TRP Sieve (suspended) Ruby: Earned 2,000,000 credits (2,070,804)AP 26/27 Jade: Earned 10,000,000 credits (10,742,251)GFN Emerald: Earned 50,000,000 credits (50,000,251)PSA Double Gold: Earned 500,000,000 credits (728,547,693)
Message 118986 - Posted: 24 Jun 2018 | 12:29:23 UTC - in response to Message 118985.
Last modified: 24 Jun 2018 | 12:31:13 UTC

The difference is due to the sieve file used as input for the CPU sieving program. The CPU program finds all the same factors, but suppresses output for anything that's already been removed from the sieve. If you look at the factorial statistics page, you'll see that some entries show a large difference between the factors found and the candidates removed. Those were run on GPU. The ones where the factors and removals are identical or very close were run on CPU. No matter which you run, the candidates removed number will be identical.

If you want to see this in action, run the CPU range again but leave out the -i fsieve_7T.txt part from the command line. You'll get the exact same output as the GPU program.

Edit: Actually I believe the CPU program doesn't even bother testing anything that's not in the sieve file and so it runs faster with a sieve file as input.

walli
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Joined: 12 Jun 16
Posts: 8
ID: 449456
Credit: 5,228,201,530
RAC: 660,541
Found 3 primes in the 2020 Tour de Primes321 LLR Turquoise: Earned 5,000,000 credits (5,334,168)Cullen LLR Turquoise: Earned 5,000,000 credits (5,002,299)ESP LLR Amethyst: Earned 1,000,000 credits (1,841,104)Generalized Cullen/Woodall LLR Silver: Earned 100,000 credits (123,484)PPS LLR Turquoise: Earned 5,000,000 credits (9,586,291)SoB LLR Jade: Earned 10,000,000 credits (10,540,541)SR5 LLR Amethyst: Earned 1,000,000 credits (1,735,467)SGS LLR Amethyst: Earned 1,000,000 credits (1,169,227)TRP LLR Amethyst: Earned 1,000,000 credits (1,322,057)Woodall LLR Ruby: Earned 2,000,000 credits (2,144,294)321 Sieve Jade: Earned 10,000,000 credits (13,542,496)Generalized Cullen/Woodall Sieve (suspended) Sapphire: Earned 20,000,000 credits (20,612,684)PPS Sieve Emerald: Earned 50,000,000 credits (53,507,883)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Silver: Earned 100,000 credits (295,388)AP 26/27 Jade: Earned 10,000,000 credits (10,127,715)GFN Sapphire: Earned 20,000,000 credits (37,265,297)PSA Double Turquoise: Earned 5,000,000,000 credits (5,054,047,170)
Message 119026 - Posted: 25 Jun 2018 | 21:58:30 UTC - in response to Message 118986.
Last modified: 25 Jun 2018 | 21:59:14 UTC

Thank you very much for making this clear because I wasn't sure about the behaviour. I could have done more testing, yes... but... ^^

Message boards : Sieving : fsievecl64.exe vs fpsieve-x86_64-linux

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