20090104, 01:11  #1 
Oct 2008
n00bville
1340_{8} Posts 
Suggestions for a new Prime95 version
In the readme.txt of prime95 v29b it is stated that:
* "The Test choice can be used to run a LucasLehmer test on one Mersenne number. Enter the Mersenne number's exponent  this must be a prime number between 5 and 560000000". Is the border of 560000000 an artificial or a technical one? How about giving people with 'monster hardware' the chance of playing with higher numbers. * In the Advanced  Test ... menu it is possible to insert a prime number. An interesting feature would be a slider to slide through the possible prime numbers for n. Additionally it would be fine to step from one prime number to the next (for instance: if one is taken). That could be possible with arrow buttons for the next prime number (at the moment I have to print out the prime number range externally or try out until the program approves the input). Greetz jb 
20090105, 04:15  #2 
May 2008
3×5×73 Posts 
I would guess the reason 560M is the limit is because the software doesn't have any FFT code to handle larger exponents.
But remember, doing a LL of a mersenne with exponent around 560M is about 200 times as hard as doing a LL on exponents currently being assigned around 40M. And you're much more likely to find a mersenne prime if you do 200 exponents around 40M than if you do only one at 560M. So I don't think there is much pressure to change the limits. I could be wrong in my assessment, though. 
20090105, 09:16  #3  
Oct 2008
n00bville
2^{5}·23 Posts 
Quote:


20090105, 12:03  #4 
Aug 2002
Termonfeckin, IE
2^{4}×173 Posts 
It is much more that 5.6 times longer as you will have to use a bigger FFT size which would mean slower iterations. Just put in a test line in your worktodo and see the completion date.

20090105, 12:18  #5  
Oct 2008
n00bville
2^{5}×23 Posts 
Quote:
For a 100M number I need around 2  3 years.  I tried it out: ***************************** [Comm thread Jan 5 13:22] PrimeNet error 40: No assignment [Comm thread Jan 5 13:22] ra: redundant LL effort, exponent: 560000011 [Comm thread Jan 5 13:22] Registering assignment: LL M559999987 [Comm thread Jan 5 13:22] URL: http://v5.mersenne.org/v5server/?v=0...0&p1=0&ss=6334 [Comm thread Jan 5 13:22] RESPONSE: [Comm thread Jan 5 13:22] pnErrorResult=40 [Comm thread Jan 5 13:22] pnErrorDetail=ra: redundant LL effort, exponent: 559999987 [Comm thread Jan 5 13:22] ==END== [Comm thread Jan 5 13:22] [Comm thread Jan 5 13:22] PrimeNet error 40: No assignment [Comm thread Jan 5 13:22] ra: redundant LL effort, exponent: 559999987 [Comm thread Jan 5 13:22] Done communicating with server. ***************************** Does that redundant LL effort mean that there are already people working on that? Additionally it seems to work to test higher exp. than 560M. http://v5www.mersenne.org/primenet/ shows exponents up to 999M, but nobody working on the +/ 560M range ... Last fiddled with by joblack on 20090105 at 12:31 

20090105, 13:18  #6  
"Jacob"
Sep 2006
Brussels, Belgium
11·173 Posts 
Quote:
Try 559999897 and 560000039... Jacob 

20090105, 19:39  #7 
"Jacob"
Sep 2006
Brussels, Belgium
76F_{16} Posts 
I timed 560000039 on core2 Quad at 2940 MHz :
One thread would take 14 years and 10 month. Four threads would take 5 yeas and 5 month. This would also mean that numbers bigger than 560M can be tested... Jacob 
20090105, 20:09  #8  
May 2008
3×5×73 Posts 
Quote:
But here is how you can figure it yourself: The test time is proportional to both the iteration time and iteration count. The iteration time is proportional to the FFT size that the test will use. The FFT size increases roughly linearly with exponent p (actually the FFT size increments in steps, but for our purposes here that isn't very important). The iteration count is p2. So roughly speaking, the test time will be proportionally about p^2. If a 40M exponent takes X days, then a 560M exponent will take ~196*X days. Since 560^2 / 40^2 = 196. Last fiddled with by jrk on 20090105 at 20:10 

20090105, 22:11  #9  
Oct 2008
n00bville
736_{10} Posts 
Quote:
Now I get the ********************************[Main thread Jan 5 21:34] Mersenne number primality test program version 25.9 [Comm thread Jan 5 21:34] Registering assignment: LL M560000039 [Comm thread Jan 5 21:34] URL: http://v5.mersenne.org/v5server/?v=0...0&p1=0&ss=5523 [Comm thread Jan 5 21:34] RESPONSE: [Comm thread Jan 5 21:34] pnErrorResult=40 [Comm thread Jan 5 21:34] pnErrorDetail=ra: already assigned, exponent: 560000039, A: 1, b: 2, c: 1 [Comm thread Jan 5 21:34] ==END== [Comm thread Jan 5 21:34] [Comm thread Jan 5 21:34] PrimeNet error 40: No assignment [Comm thread Jan 5 21:34] ra: already assigned, exponent: 560000039, A: 1, b: 2, c: 1 [Comm thread Jan 5 21:34] Done communicating with server. [Main thread Jan 5 21:34] Starting workers. ************************************* But some hours ago it worked perfect (no error message). I think the 'already assigned' algomrithm doesn´t work that good on server and/or client side ... perhaps a job for the prime95 user ... 

20090106, 06:33  #10  
"Jacob"
Sep 2006
Brussels, Belgium
11·173 Posts 
Quote:
Quote:
"560000039 No factors below 2^59 Assigned LL testing to "joblack" on 20090105" Jacob Last fiddled with by S485122 on 20090106 at 06:34 Reason: rubbed it in 

20090106, 23:45  #11  
Oct 2008
n00bville
2^{5}·23 Posts 
Quote:


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