mersenneforum.org Work for chosen exponent
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 2020-03-22, 11:23 #1 Petnek     Mar 2020 Czechia, Tábor 24 Posts Work for chosen exponent Hello, is it possible to make calculations for chosen exponent? For example this one. It's the closest exponent to my date of birth and I would appreciate a chance to take care of it Is here a way how to make calculations for it? If yes, how? And in which order? For example TF is not possible to reserve due to current active range. Thank you
 2020-03-22, 14:28 #2 LaurV Romulan Interpreter     Jun 2011 Thailand 2×13×337 Posts That exponent generates a mersenne number that already has a factor, therefore there is nothing more to calculate for it. If you want to stay as close to it as possible, go to the link you posted, place your mouse over the little arrows in the upper-left table (where the exponent is printed in big letters) and look for "next exponent without factor" respectively "previous exponent without factor". And pick those, or some other from the respective range. You will have no competition there (for who didn't want to click the link, range is 198M), because most of other users are working either below 110M, or at 332M to hunt the EFF prize, therefore it will be no other user competing for it, most probably, so you can get that exponent as simple as using the manual test page, fill what exponent you want, or just add it to the worktodo.txt using a text editor. Last fiddled with by LaurV on 2020-03-22 at 14:30
 2020-03-22, 16:01 #3 Petnek     Mar 2020 Czechia, Tábor 24 Posts OK, where factor is found, there is no more work. So I chose this one. Until when is reasonable to do TF? OK, this I found. For exponent up to 227,300,000 its 2^76 but here is next to GPU72 already 2^78. Why? TF I can reserve for GPU, but for CPU I'm able to assign nothing. Why is that? I'm getting this error msg: Code: Error code: 40 Error text: No assignment available meeting CPU, program code and work preference requirements, cpu_id: 2233562, cpu # = 0, user_id = 28284 You wrote I can just add it to worktodo.txt. How I can get hash like part of the line written into that file? I'm new in primes, so I'm not sure what is for what. Is here some sequence of tests? For example first TF, than P-1, PRP, ECM and finally LL? OK, this I found too. TF > P-1 > LL > DC. For what is PRP and ECM than? Last fiddled with by Petnek on 2020-03-22 at 16:30
 2020-03-22, 18:15 #5 Petnek     Mar 2020 Czechia, Tábor 24 Posts Yes, I have a GPU and I'm already TFing. In these times not so fast GTX960 The sequence of tests is clear to me, I hope When or how is possible to assign P-1 test to that exponent? When I can do that, is it related to not enough TF tests or I'm somehow not reaching some requirments for categories? I'm getting that error msg mentioned in previous post.
 2020-03-22, 18:27 #6 kriesel     "TF79LL86GIMPS96gpu17" Mar 2017 US midwest 4,463 Posts Welcome to the forum. You might find some of the background or reference info at https://mersenneforum.org/showthread.php?t=24607 useful. Historically LL was used for primality testing. Because of the excellent error detection of the Gerbicz error check, PRP is recommended instead of LL. Assuming no factors are found, the order is typicallyTF to the level merited by effort versus odds of finding a factor, P-1 factoring similarly, PRP and eventually PRP DC. Last fiddled with by kriesel on 2020-03-22 at 18:30
 2020-03-22, 18:30 #7 LaurV Romulan Interpreter     Jun 2011 Thailand 2·13·337 Posts (I edited my post above, crosspost, to add few phrases) There should be no issue in getting a manual assignment in that range, for either P-1 or LL/PRP. You just go to gimps manual assignments, fill P-1 and the range close to your exponent. I just got this right now (which I am not going to do, most probably I will unreserve, but just to test the reservation form): Code: PFactor=33360C59858ED75AF8680544E5387FA8,1,2,198000067,-1,76,2 You can also add such lines manually to your worktodo, and let P95 communicate with the server, to record them (use N/A for the assignment key when you add manual work). The P-1 work should be done AFTER the TF, or (depending on your system) before the last bit of TF, otherwise the work is in vain in case TF would have found a factor faster. So, if you decide to TF to 82 bits, the sequence should be TF to 81, then P-1 for about 3% or 5% chances to a factor, then TF to 82, then PRP (or LL, but right now, LL is frown here around, people want to switch to PRP for newer assignments, due to better "tolerance" for errors). Last fiddled with by LaurV on 2020-03-22 at 18:34
2020-03-22, 19:03   #8
Petnek

Mar 2020
Czechia, Tábor

24 Posts

Quote:
 Originally Posted by kriesel Welcome to the forum. You might find some of the background or reference info at https://mersenneforum.org/showthread.php?t=24607 useful. Historically LL was used for primality testing...
Thank you for the welcome. I'm just going through all of these threads, interesting informations indeed.
OK, PRP is better than LL.

Quote:
 Originally Posted by LaurV There should be no issue in getting a manual assignment in that range
I'm getting that error msg when trying to assign that exact exponent, no range around. That is not good way? How to assign P-1 just to chosen exponent?

Thank you both for further explanation of sequence of tests. I'm just getting through all those reccomended threads, so many info...

 2020-03-22, 22:46 #9 Prime95 P90 years forever!     Aug 2002 Yeehaw, FL 71×101 Posts Getting a PRP assignment implies that you have a P-1 assignment too. Both prime95 and the latest gpuOwl will do the P-1 automatically before running the PRP test. Last fiddled with by Prime95 on 2020-03-22 at 22:46
 2020-03-23, 10:12 #10 Petnek     Mar 2020 Czechia, Tábor 24 Posts Thanks for all your answers. So far I didn't find answer for this one... For which tests is wise to use GPU? Are GPUs faster on something else than TFing? In my case I have GTX960, Ryzen 5 2600, i5-2410M and partially i7-6820HQ Last fiddled with by Petnek on 2020-03-23 at 10:12
 2020-03-23, 16:49 #11 Uncwilly 6809 > 6502     """"""""""""""""""" Aug 2003 101×103 Posts 22×3×7×103 Posts In general: GPU for TF, it is almost like they were designed for this. P-1 is good on a CPU Primality checks (PRP or LL) do on a CPU. This will best help the project along. As always do what gives you pleasure. There are times that using a GPU to do a first time check is warranted (as a platform independent check of a reported prime).

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