20210508, 10:41  #1 
May 2021
7 Posts 
Complete GIMPS Beginner
Hi Everybody,
I've decided to join the quest for discovering Mersenne primes and incidentally  this is my foray into posting on a forum (so please bare with me!) This has probably been covered many times over already  but I've had a look through the forum and haven't had much luck trying to find an answer to my questions. If someone could help me out please that would be much appreciated! OK, so firstly  is there documentation / a forum thread that I can read that gives me a detailed explanation of what I am looking at in terms of my personal assignment details? For example, I see columns like 'CPU name' , 'Exponent' and 'Work Type' but I am unclear as to what they mean (especially because the number being displayed in 'Exponent' column is different from the one that I am testing in Prime95?). This is all for now  but I'm sure I'll have more questions ! Thanks in advance for any advice. Dalybe 
20210508, 11:06  #2 
Jul 2009
Germany
2×3×101 Posts 
use https://www.mersenne.org/workload/
to see the progress off all your assignments you can update the progress in prime95 manually with Advanced>manual communication>Send new expected completion date Last fiddled with by moebius on 20210508 at 11:09 
20210508, 12:28  #3 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2^{4}·7·47 Posts 
Welcome to the forum. There are some pretty good documentation files shipped in the zip file with prime95 or mprime. Read them, try some things, use the reference info found at https://mersenneforum.org/showthread...922#post521922, and have fun!

20210508, 12:51  #4 
May 2021
7_{10} Posts 
That's great  thank you @kriesel and @moebius . I will do a some more reading and investigating, thanks!

20210508, 18:57  #5 
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
3·7·461 Posts 
One of the things to note:
When doing certain types of tests, the test hast to run to the end or a major point before any results are known. PRP tests (the current standard way to check a number for being prime) is like this LL tests (which is what has been what we used to use all the time in the past) is like this P1 tests (which look for factors for numbers, so we don't have to do the longer tests) have a stage 1 and stage 2. The test can find a factor at the end of either, but not in the middle. TF (trial factoring) can find a factor at any time (essentially), thus can stop whena factor is found. 
20210510, 15:06  #6  
Mar 2019
USA
37_{16} Posts 
Quote:
1. Is the length of time a P1 takes to complete lowered at all by how high the TF has been done? It always says" Assuming no factors below 2^76" (for example). If that same exponent was instead, say, factored to 2^78 before running the P1, would the P1 test take less time? 2. Am I correct that if a PRP test is performed on an exponent that does not have a P1 test done yet, that it will do the P1 prior to running the PRP? So, running a PRP on an exponent that already has a P1 would take less time since it doesn't have to run that test first? 3. In the most simplest terms possible, can someone explain why a TF on lower exponents take LONGER than on much much larger exponents? My GTX 1080 Ti burns though high level exponents, but takes significantly longer for lower ones. 

20210510, 15:44  #7  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2^{4}×7×47 Posts 
Quote:
Quote:
Quote:
But large exponents take longer to trial factor overall, since their optimal highest bit level to TF is higher than for smaller exponents. TF effort for a bit level is about proportional to 2^{level}/exponent. There are several other details that go into it; density of primes declining further up the number line, GPU factoring kernels' complexity increasing with bit level, etc. Other readers that want more indepth info can read this. For tables, charts, scaling fits, the pdf attachment here contains those. Last fiddled with by kriesel on 20210510 at 15:59 

20210510, 15:48  #8 
Romulan Interpreter
Jun 2011
Thailand
10010101001101_{2} Posts 
1. No. For a specific B1/B2 pair, P1 will take the same amount of time, with or without any TF done. However its chances to find a factor are different. Prime95 and gpuOwl will calculate different B1/B2 knowing the TF level, in such a way to maximize your chances to find a factor.
2. It's complicate. Your PRP alone will take the same amount of time regardless of the fact that P1 was done or not. Also viceversa, the P1 will take the same amount of time alone, regardless the fact that PRP was done or not. However, where it gets complicate is the fact that P1 may found a factor, therefore saving the long PRP run, and on the long run, your total time spent doing PRP could be lower. Also, new "toys" like gpuOwl, etc, combine the PRP and P1 in one (because in the beginning the iterations are common) so the P1 may come "for free" if no factor is found. 3. Factors of 2^p1 are of the form 2kp+1. So, factors of 2^111 can be apart a multiple of 22. Factors of 2^671 can be a multiple of 67+67=134 apart. Factors of 2^1011 can be 202 apart. If you TF the two exponents (67 and 101) from, say, 2^20 to 2^21, how many possible candidates you have in each case? Last fiddled with by LaurV on 20210510 at 15:51 
20210510, 21:03  #9  
P90 years forever!
Aug 2002
Yeehaw, FL
2×3^{3}×139 Posts 
Quote:


20210511, 23:33  #10 
"Matthew Anderson"
Dec 2010
Oregon, USA
3·5·53 Posts 
Welcome to the team, Dalybe !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

20210514, 15:31  #11 
May 2021
7 Posts 
Hello again everybody  and thanks for making me feel very welcome!
Ok, so I have completed (at least I think I have completed) my first assignment. It turns out that my first one wasn't prime (surprise surprise!) and now I have been given a new one to check. What I am confused about however is why on my assignments tab it is still displaying information from the initial one which has completed? Is there another series of checks or something that has to happen before this is updated? Additionally, the 'Last Update' column says 20210508  but apparently the check was complete on 20210513. Any help or advice would be much appreciated! Cheers! Dalybe 
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