mersenneforum.org How to do P-1 on a PRP assignment that has no P-1 work done?
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 2021-06-17, 15:44 #1 themoon123   Apr 2021 23 Posts How to do P-1 on a PRP assignment that has no P-1 work done? I just got a RX 6800 XT today and will be running PRP on it mostly. I got a PRP assignment from the manual page but it hasn't gone through a P-1 test yet. How do i do a P-1 test before the PRP test like prime95 does? I'm running gpuowl 7.2 on Windows 10.
 2021-06-17, 16:02 #2 firejuggler     "Vincent" Apr 2010 Over the rainbow 22·13·53 Posts Pminus1=N/A,1,2,23562083,-1,1200000,36000000,70 aka AID,k,base,exponent,minus/plus, B1,B2, how far factored. but if you specify how far factored, P95 will calculate the best bound with the B1 you provided Last fiddled with by firejuggler on 2021-06-17 at 16:46
2021-06-17, 16:20   #3
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

2·373 Posts

Quote:
 Originally Posted by themoon123 I just got a RX 6800 XT today and will be running PRP on it mostly. I got a PRP assignment from the manual page but it hasn't gone through a P-1 test yet. How do i do a P-1 test before the PRP test like prime95 does? I'm running gpuowl 7.2 on Windows 10.
GpuOwl, version 7.2, is doing P-1 automatically at the same time as PRP because the inner maths of P-1 and PRP allow it. For how to set the worktodo line such that it does this, consult Kriesel's reference material. Specifically, look for worktodo entry formats.

Could you please compare your performance in v7.2 and v6.11? I would like to see those results. The first few iteration outputs should be sufficient from each version. A screenshot is great, but simply giving me numbers for us/it (microseconds per iteration) for each version is enough. Thanks in advance

 2021-06-17, 16:21 #4 themoon123   Apr 2021 816 Posts Sorry, how do i calculate which bounds b1 and b2 should be? Is there some automated way to do p-1 on an exponent before PRP?
2021-06-17, 17:35   #5
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

2EA16 Posts

Quote:
 Originally Posted by themoon123 Sorry, how do i calculate which bounds b1 and b2 should be? Is there some automated way to do p-1 on an exponent before PRP?
If you put the following form of the worktodo line into your gpuOwl worktodo, it will do P-1 automatically.

PRP=AID,1,2,exponent,-1,tflevel,1

The one at the end is important, it tells the gpuOwl that P-1 hasn't been done yet. AID is optional, but if you are getting work from PrimeNet (i.e. mersenne.org page), you should have one.

2021-06-17, 17:59   #6
themoon123

Apr 2021

23 Posts

Quote:
 Originally Posted by Viliam Furik If you put the following form of the worktodo line into your gpuOwl worktodo, it will do P-1 automatically. PRP=AID,1,2,exponent,-1,tflevel,1 The one at the end is important, it tells the gpuOwl that P-1 hasn't been done yet. AID is optional, but if you are getting work from PrimeNet (i.e. mersenne.org page), you should have one.
Ah.. Thank you! The assignment i got has a 2 at the end, what does that mean?

Last fiddled with by themoon123 on 2021-06-17 at 18:24

2021-06-17, 18:37   #7
themoon123

Apr 2021

810 Posts

Quote:
 Originally Posted by Viliam Furik GpuOwl, version 7.2, is doing P-1 automatically at the same time as PRP because the inner maths of P-1 and PRP allow it. For how to set the worktodo line such that it does this, consult Kriesel's reference material. Specifically, look for worktodo entry formats. Could you please compare your performance in v7.2 and v6.11? I would like to see those results. The first few iteration outputs should be sufficient from each version. A screenshot is great, but simply giving me numbers for us/it (microseconds per iteration) for each version is enough. Thanks in advance
I tested both 6.11 and 7.2 and got the following:

6.11: 1002 us/it
7.2: 1017 us/it

2021-06-17, 18:46   #8
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

2×373 Posts

Quote:
 Originally Posted by themoon123 Ah.. Thank you! The assignment i got has a 2 at the end, what does that mean?
2 means, as far as I know, that if a factor is found by P-1, 2 tests will be saved. That's a remnant after LL testing, where this is true. For PRP, with proof generation and certification, this is no longer true, because only 1 test is being run; the certification is only a tiny fraction of the entire test.

For the gpuOwl 1 is thus an OK choice.

Quote:
 Originally Posted by themoon123 I tested both 6.11 and 7.2 and got the following: 6.11: 1002 us/it 7.2: 1017 us/it
Thanks! Really appreciated.

 2021-06-17, 18:46 #9 kriesel     "TF79LL86GIMPS96gpu17" Mar 2017 US midwest 613610 Posts If P-1 is needed, gpuowl 7.x do PRP from the start, and P-1 stage 1 powers are assembled from PRP interim computations, which reduces stage 1 cost to about 10% of a standalone run. However, this greatly increases stage 1 memory requirements. (Gpuowl 7.x will run the stage 1 GCD in parallel with PRP, and if no factor is found in stage 1, pause the PRP to perform P-1 stage 2 computations, then if no factor is found in stage 2, continue the PRP to completion.) Also combined P-1 and PRP runtime of V6.11-380 and close versions are for most FFT lengths faster than v7.x. A detailed benchmarking versus FFT lengths and selected Gpuowl versions is available for Radeon VII as last attachment of https://www.mersenneforum.org/showpo...35&postcount=2. Gpuowl provides default bounds, but they are larger than optimal for pure Mersenne prime hunting. Bounds can be specified on a per-worktodo-entry basis. See https://www.mersenneforum.org/showpo...9&postcount=20 for choosing bounds. Code: 6.11: 1002 us/it 7.2: 1017 us/it For what exponent or fft length? Factory standard clocking on the GPU? Last fiddled with by kriesel on 2021-06-17 at 18:50
2021-06-18, 05:55   #10
themoon123

Apr 2021

23 Posts

Quote:
 Originally Posted by kriesel If P-1 is needed, gpuowl 7.x do PRP from the start, and P-1 stage 1 powers are assembled from PRP interim computations, which reduces stage 1 cost to about 10% of a standalone run. However, this greatly increases stage 1 memory requirements. (Gpuowl 7.x will run the stage 1 GCD in parallel with PRP, and if no factor is found in stage 1, pause the PRP to perform P-1 stage 2 computations, then if no factor is found in stage 2, continue the PRP to completion.) Also combined P-1 and PRP runtime of V6.11-380 and close versions are for most FFT lengths faster than v7.x. A detailed benchmarking versus FFT lengths and selected Gpuowl versions is available for Radeon VII as last attachment of https://www.mersenneforum.org/showpo...35&postcount=2. Gpuowl provides default bounds, but they are larger than optimal for pure Mersenne prime hunting. Bounds can be specified on a per-worktodo-entry basis. See https://www.mersenneforum.org/showpo...9&postcount=20 for choosing bounds. Code: 6.11: 1002 us/it 7.2: 1017 us/it For what exponent or fft length? Factory standard clocking on the GPU?
I got these numbers on an ASUS TUF OC 6800 XT with factory overclocking. The exponent i'm testing is 111482183.

So ideally i would get the bounds i should use from here right? https://www.mersenne.ca/exponent/111482183 under GPU72 bounds?

Last fiddled with by themoon123 on 2021-06-18 at 06:03

 2021-06-18, 08:45 #11 LaurV Romulan Interpreter     "name field" Jun 2011 Thailand 987810 Posts If you are not happy with the default bounds (which for the most cases are good enough, but you may want to adjust them a bit higher if you are in the game for finding factors, or a bit lower, as anteposters said, if your goal is to find a large prime), or if you just wanna dirty your hands with P-1 bulk factoring, then you should better take your bounds from here, according with how many factors you want to find per 100 exponents, the power of your hardware (in GHzDays per day) and your tolerance for pain (i.e. patience). Note that if you P-1 in bulk in a range, to find factors, then you don't need to compute for every exponent. Put some exponent in the middle of the range you are targeting, select your desired probabilities, and then go with those B1/B2 for the whole range. Play a bit with the form first to see what's what (for example, yo don't need to fill all fields, if you let fields empty, the best values will be suggested for you), it is very easy to understand, and useful, (i.e. it saves your time and resources, and it helps the project better than if you pick the limits from the thin air, or from the "neighbors" ). If it is unclear, ask. Last fiddled with by LaurV on 2021-06-18 at 08:53

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