20200210, 19:51  #1 
Mar 2004
509 Posts 
How to manually reserve TF
First, I know, GPU and all. I have an old 32 bit Lenovo laptop that I'm pretty sure can't do mfacto and mfactc. This laptop will be on MAYBE 50 hours per year. So I want to set it to do TF on a Mersenne I've already reserved. But I don't know how to do that. I see the worktodo does Factor=[HEX],exponent,lowerbound,upperbound . I don't know how to deal with that hex.
I asked a similar question about a Chromebook but I'm probably not going to do anything there. Last fiddled with by JuanTutors on 20200210 at 19:53 
20200210, 19:58  #2 
If I May
"Chris Halsall"
Sep 2002
Barbados
3×3,191 Posts 
Change it to be "N/A", and then Prime95/mprime won't try to reserve it from Primenet, but will report the results once completed.
You're aware that TF'ing on a CPU is a waste of electrons, but they're yours to do with as you wish... 
20200210, 20:03  #3 
Mar 2004
509 Posts 
It's that or nada for a 7 year old laptop that will be on for minutes per day.

20200210, 20:14  #4 
Mar 2004
509 Posts 
I know it's greedy to use the tiny number of minutes I am running this to work on my own Mersennes but honestly when I say max 50 hours, it's more like "I haven't turned on this laptop in 2 years" minutes. It's just going to do occasional calculations, and periodic P1 on my Mersennes will require time to do GCD, and the chance of the laptop being on that long is low. Unless I'm wrong about this laptop being able to do mfacto/mfactc and unless that would be faster on this old laptop, that seems to be my option.

20200211, 00:31  #5  
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
2×7×331 Posts 
Quote:


20200211, 00:42  #6 
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
9565_{10} Posts 
PRP on cofactors is a fast operation too.

20200211, 02:34  #7 
Mar 2004
1FD_{16} Posts 

20200211, 05:18  #8 
"Curtis"
Feb 2005
Riverside, CA
3^{4}·59 Posts 
You shouldn't do TF, period. ECM is fine, or just accept that that particular machine isn't a useful contributor to GIMPS just like the machine you carry in your pocket daily.

20200212, 11:35  #9 
"Graham uses ISO 8601"
Mar 2014
AU, Sydney
11110001_{2} Posts 
Indeed 50 hours per year is of little benefit to the project, and any assignment that you may have held from the outset would likely expire before completion, and likely be completed by another player.

20200212, 12:31  #10  
Mar 2004
509_{10} Posts 
Quote:
Second, again, just doing some light TF and ECM on a project I'm already doing PRP with on another computer on the off chance I find a factor and save me whatever time remains from the PRP test. From what I gather, the probability of finding a factor between 2^81 and 2^82 is slightly above 1%, which is greater than 0%. I get that it's slow, but I haven't heard an actual reason why I should opt for no work over some work, when any work is positive work. Last fiddled with by JuanTutors on 20200212 at 12:32 

20200212, 14:02  #11  
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
255D_{16} Posts 
Quote:
But, what people are trying to tell you is that some work is really of zero value. Doing ECM factoring on a number that is years ahead of the first time wave front is nonsensical. ECM is best used for low numbers that have had a good amount of TF and P1 done. If you want to make maximum use of your machine for the GIMPS project overall, I would suggest that you set it to do PRP (or PRPDC) on Mersenne number cofactors. The reasons are: It is not a huge amount of work in terms of GHz days per assignment. You will not be holding up any milestones. Your assignment will not likely expire after a couple of months of slow progress. It will help the project along, by revealing an important bit of data. If your test does not match, a TC can determine if your machine is still sane. Just because you are obsessed with a different number, doing any testing you can on it does not make sense. The only reason to do extra TF or P1 on a number that is undergoing PRP or LL testing, is to try to "break" an number that is claimed to be prime, while the DC is being done. Doing ECM on such a number is foolhearty. It is like trying to empty a supertanker with a bucket. 

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