20210524, 22:05  #111 
"Rich"
Aug 2002
Benicia, California
10100011111_{2} Posts 

20210524, 22:12  #112 
"Jane Sullivan"
Jan 2011
Beckenham, UK
2^{2}·5·13 Posts 
Feedback
I've just managed to factor a C190 into PRP26, PRP52 and PRP113 using YAFU 2.02. It took 5 days and 5 hours, but that's down to my awful hardware. I am pleased with this.
If anyone's interested the C190 was 30^128 + 17^128. Incidentally, I'm sure I've seen something posted about this here before, but what's the largest number of decimal digits YAFU will handle? 
20210525, 20:09  #113 
"Daniel Jackson"
May 2011
14285714285714285714
2^{3}×83 Posts 
I've run partial factorizations of larger numbers (up to 900 digits; sometimes Yafu will crash on numbers >1000 digits, but that was before I upgraded to 2.x), and sometimes I'll get a full factorization, but it's very rare.
Any chance you could post the factors of 30^128+17^128 on FactorDB? It still says it's a C190: http://www.factordb.com/index.php?id...00000441930677 
20210526, 13:14  #114  
"Jane Sullivan"
Jan 2011
Beckenham, UK
2^{2}×5×13 Posts 
Quote:
Quote:
How many of these Homogeneous Cunninghams should go onto FactorDB? I've got a lot of them that I've not been posting after someone complained about them a few years back. 

20210526, 14:11  #115 
"Ed Hall"
Dec 2009
Adirondack Mtns
EF1_{16} Posts 
sigma() appears to be broken
Code:
05/26/21 10:01:49 v1.35beta @ math97, System/Build Info: Using GMPECM 7.0.5dev, Powered by GMP 6.2.0 detected Intel(R) Core(TM) i72600 CPU @ 3.40GHz detected L1 = 32768 bytes, L2 = 8388608 bytes, CL = 64 bytes measured cpu frequency ~= 3392.250200 using 1 random witnesses for RabinMiller PRP checks . . . cached 664579 primes. pmax = 9999991 >> sigma(28,1) 56 >> Code:
YAFU Version 2.0 Built with GCC 9 Using GMPECM 7.0.5dev, Powered by GMP 6.2.0 Detected Intel(R) Core(TM) i72600 CPU @ 3.40GHz Detected L1 = 32768 bytes, L2 = 8388608 bytes, CL = 64 bytes Using 1 random witness for RabinMiller PRP checks Cached 664579 primes; max prime is 9999991 . . . >> sigma(28,1) ans = 1 >> 
20210526, 15:52  #116  
Sep 2009
2,089 Posts 
Quote:
I think I once complained about a load of small unfactored ones being added to factordb (I am running a script to factor small number iin factordb, it went to the trouble of factoring them only to find them done when it tried to submit the result). Chris 

20210527, 12:07  #117 
"Ben"
Feb 2007
2^{2}×3×293 Posts 
Version 2.03 is now available with recently reported bugs fixed. Thanks Stargate38, richs, and EdH!

20210527, 13:38  #118 
"Ed Hall"
Dec 2009
Adirondack Mtns
3^{2}×5^{2}×17 Posts 
Great! Thanks for all your work!

20210528, 15:12  #119 
"Rich"
Aug 2002
Benicia, California
51F_{16} Posts 
Thanks, Ben. Your efforts are most appreciated!

20210530, 12:53  #120 
Apr 2020
16D_{16} Posts 
There appears to be a bug in SNFS polynomial selection for (at least) the k*b^n+1 and b^n+k forms, for example:
Code:
$ yafu "snfs(1281979*2^520+1,615852095139018818180740532155742854813285752039357209617222174313731523072704248288595303399267379211703243385678043310396893565702501281889421988426549324889)" Applying tune_info entry for LINUX64  Intel(R) Core(TM) i58500 CPU @ 3.00GHz YAFU Version 2.02 Built with GCC 9 Using GMPECM 7.0.5dev, Powered by GMP 6.2.1 Detected Intel(R) Core(TM) i58500 CPU @ 3.00GHz Detected L1 = 32768 bytes, L2 = 9437184 bytes, CL = 64 bytes Using 1 random witness for RabinMiller PRP checks Cached 664579 primes; max prime is 9999991 =============================================================== ======= Welcome to YAFU (Yet Another Factoring Utility) ======= ======= [email redacted] ======= ======= Type help at any time, or quit to quit ======= =============================================================== >> nfs: checking for job file  no job file found nfs: checking for poly file  no poly file found nfs: commencing nfs on c163: 4400263219768289455901391102252782697640926698321207262715052435471611732354471854022013442787765424467619673990669619452785804526944371659099920107307694926331905 nfs: searching for brent special forms... nfs: input divides 1281979*2^520 + 1 gen: ======================================================== gen: considering the following polynomials: gen: ======================================================== Error: M=1361129467683753853853498429727072845824 is not a root of f(x) % N n = 615852095139018818180740532155742854813285752039357209617222174313731523072704248288595303399267379211703243385678043310396893565702501281889421988426549324889 f(x) = + 1281979*x^4 + 0*x^3 + 0*x^2 + 0*x^1  1*x^0 Remainder is 615852095139018818180740532155742854813285752039357209617222174313731523072704248288595303399267379211703243385678043310396893565702501281889421988426549324887 Error: M=20282409603651670423947251286016 is not a root of f(x) % N n = 615852095139018818180740532155742854813285752039357209617222174313731523072704248288595303399267379211703243385678043310396893565702501281889421988426549324889 f(x) = + 1281979*x^5 + 0*x^4 + 0*x^3 + 0*x^2 + 0*x^1  1*x^0 Remainder is 615852095139018818180740532155742854813285752039357209617222174313731523072704248288595303399267379211703243385678043310396893565702501281889421988426549324887 nfs: no snfs polynomial with small coefficients found nfs: failed to find snfs polynomial! Also, I notice that the required ECM effort is not reduced when an SNFS special form is detected, necessitating a manual change to pretest_ratio. 
20210531, 21:18  #121 
"Ed Hall"
Dec 2009
Adirondack Mtns
EF1_{16} Posts 
Sorry if I'm becoming annoying, but the current "silent" option doesn't act as before. I can (re)write my scripts around it (or use YAFU 1...), but the original YAFU performed thusly:
Code:
$ ./yafu "sigma(28,1)28" silent 28 $ YAFU 2... performs in this manner: Code:
$ ./yafu "sigma(28,1)28" silent ans = 28 $ Thanks for all your development work. 
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