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 2009-06-17, 09:24 #1 spyros   Jun 2009 Athens Greece 5 Posts prime 95 notation hello i am new in this forum i get "trial factoring M58707931 to 2^69 x% complete" messages what M58707931 to 2^69 standard notation is? thank you
 2009-06-17, 10:28 #2 spyros   Jun 2009 Athens Greece 516 Posts notation trial factoring is giving me messages like M58703971 to 2^69 is x%complete. what is the meaning of this?
2009-06-17, 10:49   #3
10metreh

Nov 2008

2·33·43 Posts

Quote:
 Originally Posted by spyros trial factoring is giving me messages like M58703971 to 2^69 is x%complete. what is the meaning of this?
Don't you know what the % symbol means?

 2009-06-17, 12:00 #4 spyros   Jun 2009 Athens Greece 1012 Posts i am asking what is the meaning of "M58703971 to 2^69"? Last fiddled with by spyros on 2009-06-17 at 12:14
 2009-06-17, 12:06 #5 TimSorbet Account Deleted     "Tim Sorbera" Aug 2006 San Antonio, TX USA 11·389 Posts I'll break it down: Trial factoring means dividing by many small numbers to see if any divide the large number. For more info about how the number is quickly divided (among other GIMPS-related mathematics) see http://v5www.mersenne.org/various/math.php M58707931 means 2^58707931-1. For general info on Mersenne numbers see Mersenne prime 2^69 means 2 times itself 69 times. So "trial factoring M58707931 to 2^69" means we're dividing 2^58707931-1 by every number between 2^68 and 2^69 (the numbers below 2^68 have already been checked) to see if any divide the number exactly. If any do, then we know that the number is not prime.
2009-06-17, 12:38   #6
Uncwilly
6809 > 6502

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Aug 2003
101×103 Posts

252108 Posts

Quote:
 Originally Posted by Mini-Geek So "trial factoring M58707931 to 2^69" means we're dividing 2^58707931-1 by every number between 2^68 and 2^69 (the numbers below 2^68 have already been checked)
all potential factors

2009-06-17, 12:40   #7
Uncwilly
6809 > 6502

"""""""""""""""""""
Aug 2003
101×103 Posts

23·1,361 Posts

Quote:
 Originally Posted by spyros i am asking what is the meaning of "M58703971 to 2^69"?

 2009-06-17, 12:50 #8 spyros   Jun 2009 Athens Greece 5 Posts i see. There may be other prime numbers between merssenne primes?
 2009-06-17, 12:59 #9 ATH Einyen     Dec 2003 Denmark 1101011010102 Posts 258707931-1 might be prime. The first check is testing all numbers up to a certain limit to see if they are a factor of 258707931-1. Then Prime95 does a longer test called P-1 to test for larger factors, and finally if we still don't know any factors, Prime95 starts the long primality test which is called Lucas-Lehmer test (LL test). Last fiddled with by ATH on 2009-06-17 at 13:03
2009-06-17, 13:08   #10
Uncwilly
6809 > 6502

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Aug 2003
101×103 Posts

23×1,361 Posts

Quote:
 Originally Posted by spyros There may be other prime numbers between merssenne primes?
There are other primes between merseenes. It is just that checking mersennes is so very much easier than checking other numbers that size.

2009-06-17, 13:11   #11
Uncwilly
6809 > 6502

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Aug 2003
101×103 Posts

23×1,361 Posts

Quote:
 Originally Posted by ATH 258707931-1 might be prime. The first check is testing all numbers up to a certain limit to see if they are a factor of 258707931-1.
Again all potential factors of the given prime ar checked (up to the size mentioned). If you see the math section referenced above, you will see that any pontential factor is a function of the exponent (58707931 in your case), this makes it easier to check for factors.

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