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2004-03-22, 13:35   #23
ET_
Banned

"Luigi"
Aug 2002
Team Italia

4,751 Posts

Quote:
 Originally Posted by wblipp What methods are you using to filter the k values before determining 2kp+1? We only need to test prime values of 2kp+1, so various sieving methods are possible.
I'm checking factors mod 120 instead of 1 or 7 mod 8, and apply primality checking up to (around) 7000. Checking for higher factors would slow subsequent modulo operations on the Mersenne number even if it gets a higher number of K sieved out..

I am still working on source code to translate it into English and eliminate debug calls. Two people have already asked me for the source, if you are interested I can send it to you also.

Meanwhile I will take the range of 3,321,928,171 a bit (or two...) further.

Finally, I would like to thank Andreas Pipp's work (Andi314): he prompted me towards the right path with his program using Crandall libraries.

Luigi

 2004-03-22, 16:17 #24 ET_ Banned     "Luigi" Aug 2002 Team Italia 4,751 Posts 3,321,928,171 no factor up to 63.001 bits, k=1,391,351,436 Going up to 67 bits... BTW, I also wrote a version of the program that accepts a batch textfile with exponents and start-end bits... Luigi
2004-03-22, 22:41   #25
ET_
Banned

"Luigi"
Aug 2002
Team Italia

4,751 Posts

Quote:
 Originally Posted by ET_ I also wrote a version of the program that accepts a batch textfile with exponents and start-end bits... Luigi
Sorry for the auto-quote... editing is disabled

I mean, we may have a batch of "billion" exponents and try them up to (say) 58 bits to gather some more fators and play with them.

Luigi

2004-03-23, 02:59   #26
wblipp

"William"
May 2003
New Haven

2·32·131 Posts

Quote:
 Originally Posted by ET_ 3,321,928,171 no factor up to 63.001 bits, k=1,391,351,436 Going up to 67 bits...
The next two primes have easy factors
M( 3321928189 )C: 312261249767
M( 3321928189 )C: 43284724302671
M( 3321928217 )C: 1166521668825287

But M(3321928217) is also stubborn. If you send the program, I'll start a machine on trial factoring this one.

William

 2004-03-23, 03:30 #27 wblipp     "William" May 2003 New Haven 2·32·131 Posts Should be: But M(3321928219) is also stubborn. If you send the program, I'll start a machine on trial factoring this one. William
 2004-03-24, 08:09 #28 ET_ Banned     "Luigi" Aug 2002 Team Italia 4,751 Posts 3,321,928,171 no factor up to 66.034 bits, k>11,000,000,000 Still going up to 67 bits... and working with an old 250 MHz PII. William, I'll repost my program as soon as I implement a stronger resuming algorithm (by the end of the week) Luigi Last fiddled with by ET_ on 2004-03-24 at 08:10
2004-03-26, 12:39   #29
ET_
Banned

"Luigi"
Aug 2002
Team Italia

4,751 Posts

Quote:
 Originally Posted by ET_ William, I'll repost my program as soon as I implement a stronger resuming algorithm (by the end of the week) Luigi
And here it is

Many thanks to Nick Fortino who implemented a trick to gain another 5% of speed

Factor3_1 now can use the -r switch to resume from his status.txt file.

Now a question: I have a batch version of this program, and a list of about 3300 prime exponents starting from 3321928241,1,50 and ending with 3321999991,1,50 to feed it.

We could start a *real* "Billion Project", sieving those exponents up to 50 bits, sending factors to Will Edgington and factoring deeper the tough ones.

I could coordinate the ranges and the found factors. We won't find any prime number this way, but projects starting in the next 10 years will have to use our far-seeing effort

Is anybody interested in this work?

Luigi

Last fiddled with by ET_ on 2004-03-26 at 12:40

2004-03-26, 13:20   #30
ET_
Banned

"Luigi"
Aug 2002
Team Italia

4,751 Posts

Quote:
 Originally Posted by ET_ And here it is
I say HERE it is. Due to a small glith in the previous version, here is the REAL one to download. Xyzzy may you please cancel the file attached to the previous post?

Luigi
Attached Files
 factor3_1.zip (12.0 KB, 367 views)

 2004-03-26, 13:32 #31 ET_ Banned     "Luigi" Aug 2002 Team Italia 475110 Posts Code: M3321928171 no factor from 2^61 to 2^67. Luigi
2004-03-26, 15:24   #32
Xyzzy

"Mike"
Aug 2002

746210 Posts

Quote:
 Originally Posted by ET_ I could coordinate the ranges and the found factors. We won't find any prime number this way, but projects starting in the next 10 years will have to use our far-seeing effort
You could work this with the >79.3M LMH project if you want, let me know and we'll make you a co-mod over there...

2004-03-26, 16:27   #33
ET_
Banned

"Luigi"
Aug 2002
Team Italia

4,751 Posts

Quote:
 Originally Posted by Xyzzy You could work this with the >79.3M LMH project if you want, let me know and we'll make you a co-mod over there...
That sounds great!

I guess someone has the full list of found exponents, their factors and their bit depth... we could accomodate the results on a web page.

Luigi

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