20120229, 05:51  #12  
"Ben"
Feb 2007
23×163 Posts 
Quote:
Quote:


20120229, 08:06  #13 
Dec 2008
179 Posts 
It depends on what you mean by "faster". Usually you do ECM for time x which succeeds with probability p, and if it fails you do QS for time y, so the expected total time is x+(1p)y; this is less than y iff x/p<y. With the suggested change you would do ECM for x and QS for x at the same time and then possibly QS for yx, so expected wallclock time is x+(1p)(yx) but expected processor time is 2x+(1p)(yx); the expected wallclock time is less than y iff x<y, but the expected processor time is less than y iff x(1+1/p)<y. So if you only have a single number to factor and don't mind wasting processor time, by all means do ECM on one thread and QS on another at the same time (which should be simple enough to do manually), but YAFU should be optimized to minimize processor time.

20120229, 08:49  #14 
Romulan Interpreter
"name field"
Jun 2011
Thailand
10100000101101_{2} Posts 
No, and no. For a simple and objective reason: I am out of "siqs range". There was a time when I was doing mostly siqs, but now I involved better computers and all my aliquots advanced in the 120150 digits range and I very seldom try to factor lower stuff. You remember there was a time when I continuously bothered you about siqs (which I still understand, contrary to nfs which I only partially understand), but that time is now "past" as long as I don't need too often to factor under100digits composites. Maybe someday I would move my ass and put the hand on the book and try to workout the nfs. But for now I am just using it blind.

20120229, 08:59  #15 
Romulan Interpreter
"name field"
Jun 2011
Thailand
5×11^{2}×17 Posts 
Shouldn't be px+(1p)y? And in fact you get always a better number, no matter if you minimize the wall clock time or the processor time (assuming they are directly proportional), and then no matter if you do one or more factorizations. More factorizations are just one factorization at the power of n, hehe, or say, onebyone factorization. As said in the former post, this only affects the siqs, where consumed time is comparable with the ecm consumed time (for a siqsrange composite) and you know exactly how many relations you will need, and you can maximize the efficiency (minimize the time spent in ecm+siqs). For nfs  where such optimization would be more wanted  it can not be done (or not so easy, or I don't have enough knowledge about nfs to see how it could be done).

20120229, 13:56  #16  
"Ed Hall"
Dec 2009
Adirondack Mtns
5,419 Posts 
Quote:
Once the new console window is running, the GUI would basically sit, or possibly watch any generated "log" files. It would not interface with the running instance of YAFU, other than terminating it, if that is desired. At this point I'm looking at only a Windows interface, written in C++, compiled via DevC++ with source code and binary available. I'd like to expand it to linux in the future, but I've never been happy with any of the GUI packages I've studied for linux, yet. It would probably look quite different, but here's an image of AliWin2 running Aliqueit: Last fiddled with by EdH on 20120229 at 13:57 

20120229, 15:45  #17  
"Ben"
Feb 2007
3749_{10} Posts 
Quote:


20120328, 01:04  #18 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
7221_{10} Posts 
PRP > P
I typed in a random number:
Code:
>> factor(134085979082345987629876542398717) factoring 134085979082345987629876542398717 using pretesting plan: normal no tune info: using qs/gnfs crossover of 95 digits div: primes less than 10000 fmt: 1000000 iterations rho: x^2 + 3, starting 1000 iterations on C29 rho: x^2 + 2, starting 1000 iterations on C29 rho: x^2 + 2, starting 1000 iterations on C24 Total factoring time = 0.0006 seconds ***factors found*** P4 = 4057 P5 = 75883 P5 = 33289 PRP20 = 13083776549900283863 Edit: What yafu reported as PRP45 and PRP46, factordb report now as P. Last fiddled with by Dubslow on 20120328 at 02:02 
20120328, 03:52  #19 
"Ben"
Feb 2007
23×163 Posts 
There are certainly algorithms that can prove primalty of such small numbers very quickly, I just haven't implemented any of them (I'm thinking in particular of APRCL). Pretty much all of the time I'm ok with the 1 chance in 4^20 that the PRP's have of actually being composite. If there ever comes a day when I just have to know for sure, I'll go to somewhere like WolframAlpha or Alpertron's webpage :)
Anyone have an APRCL implemention they would want to contribute to YAFU? 
20120328, 05:16  #20 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
3·29·83 Posts 
How about
Code:
>> q 
20120328, 05:34  #21  
Aug 2006
2^{2}·3·499 Posts 
Quote:
Quote:
Last fiddled with by CRGreathouse on 20120328 at 05:35 

20120328, 07:25  #22 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
3×29×83 Posts 
Well, it says "xxx is a prime number.", but I suppose you're right, it could just be a PRP that's "catered to the masses". OTOH, it's clear that FactorDB does use an actual primality test, and it's able to run those on 80+ digit numbers in less than a second, so it is perfectly reasonable. And thanks for the pointer, while I can't do much with it, eventually I will be slightly happier when I use YAFU. As a newcomer only just stretching his sights beyond GIMPS, I had lots of fun using it.

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