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2004-12-10, 07:11   #34
wblipp

"William"
May 2003
New Haven

2·32·131 Posts

Quote:
 Originally Posted by Joshua2 M3321931267 has a factor: 1078901975478791259223 Do you check the factors reported, how? Does the program check every odd number?
1. Did you quit M3321931267 when you found the factor, or continue through 270?

2. Is M3321931993 still running?

3. I confirm every reported factor by using the Zmath Excel addin, and confirming that zpowmod(2, exponent, prime) is 1. Zmath is free and handles numbers up to 256 digits.

4. I don't think Luigi has discussed the full details of how the program works. We know that every divisor of 2p-1 is of the form 2kp+1, so Luigi starts with a large list of k values (probably as a bit map rather than a real list). Then he knows that every 3rd number is divisible by 3 and every 5th one is divisible by 5, etc, so he knocks out all the k's for which 2kp+1 is divisible by some small prime. I don't know how high he goes. I don't know if it is then quicker to do a PRP test on the remaining 2kp+1 values or just do the trial division.

William

 2004-12-11, 01:20 #35 Joshua2     Sep 2004 10258 Posts 1. I continued through 2^70. (70.023 actually) 69.87 was that factors bit depth. The last factor I found (the one before this) I think I might have stopped as soon as I saw it and not let it continue. Not sure. Should I let it finish that bit depth next time, or no? 2. M3321931993 no factor from 2^62 to 2^64. (sorry) 3. Aren't these billion digit numbers? ie greater than 256 ;) i suppose the factors have to be shorter than 256 digits is all it means. 4. As long as using more memory or hard drive space wouldn't speed it up its fine with me. :) I've taken 3321931831 to 67 (67.781) no factors found. It appears that Carlo and I are working on the same number. Don't know what to do, but i am continuing for now. M3321931099 no factor under 2^72. Continiuing to 73. M3321931289 no factor under 2^70. Continiuing to 73. Last fiddled with by Joshua2 on 2004-12-11 at 01:23
2004-12-11, 05:32   #36
wblipp

"William"
May 2003
New Haven

235810 Posts

Quote:
 Originally Posted by Joshua2 I've taken 3321931831 to 67 (67.781) no factors found. It appears that Carlo and I are working on the same number. Don't know what to do, but i am continuing for now.
According to my summary at http://ElevenSmooth.com/Billion.html , Carlo is doing ...1381 and nobody was doing ...1831. Note the 3 an 8 are swapped.

2004-12-11, 16:29   #37
ET_
Banned

"Luigi"
Aug 2002
Team Italia

128F16 Posts

Quote:
 Originally Posted by wblipp According to my summary at http://ElevenSmooth.com/Billion.html , Carlo is doing ...1381 and nobody was doing ...1831. Note the 3 an 8 are swapped.
Well, accroding to http://www.mersenneforum.org/showpos...2&postcount=19
Carlo si doing 3321931363 not 3321931381, so 3321931381 would be free.

According to http://www.mersenneforum.org/showpos...1&postcount=28 Thomasn is doing 3321931919 to 70 bits.

Luigi

Last fiddled with by ET_ on 2004-12-11 at 16:34

 2004-12-11, 16:52 #38 Joshua2     Sep 2004 10000101012 Posts I'm sorry I had a typo. I did mean ...1381. So I have taken that to 68 now. no factors yet. ...1831 is still at 64. Sorry guys. Do you think that doing multiple numbers at once like newpgen would speed things up?
 2004-12-18, 17:06 #39 thomasn   Jun 2003 2×59 Posts M3321931919 no factor from 2^60 to 2^70. Thomasn
 2004-12-20, 17:19 #40 hemster   Apr 2004 PDX 228 Posts 3321928601 no factor 2^73 Make that 4@ 2^73 no factor What next.... Mark
 2004-12-21, 03:49 #41 Doorbasher   Aug 2004 22·3 Posts M3321930323 no factor to 2^72, taking it to 73.
 2004-12-27, 21:39 #42 ET_ Banned     "Luigi" Aug 2002 Team Italia 128F16 Posts Matteo Monti wrote: "M3321931993 no factor from 2^64 to 2^66." He will take the search to 2^68 Luigi
 2005-01-12, 12:31 #43 ET_ Banned     "Luigi" Aug 2002 Team Italia 112178 Posts M3321931363 no factor from 2^60 to 2^72. Luigi & Carlo
 2005-01-13, 18:02 #44 Joshua2     Sep 2004 53310 Posts No factors in M3321931099 to 73.

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