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-   -   YAFU 2.0 (https://www.mersenneforum.org/showthread.php?t=26681)

richs 2021-05-24 22:05

[QUOTE=bsquared;578988]Thanks for the report. This is due to the same bug Stargate reported and will be fixed after I'm able to re-build the project tonight.[/QUOTE]

Thanks! I'll get the revised executable when available.

BudgieJane 2021-05-24 22:12

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?

Stargate38 2021-05-25 20:09

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: [url]http://www.factordb.com/index.php?id=1100000000441930677[/url]

BudgieJane 2021-05-26 13:14

[QUOTE=Stargate38;579083]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.[/QUOTE]
Thank you.

[QUOTE=Stargate38;579083]Any chance you could post the factors of 30^128+17^128 on FactorDB? It still says it's a C190: [url]http://www.factordb.com/index.php?id=1100000000441930677[/url][/QUOTE]
Done.
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.

EdH 2021-05-26 14:11

sigma() appears to be broken
 
[code]05/26/21 10:01:49 v1.35-beta @ math97, System/Build Info:
Using GMP-ECM 7.0.5-dev, Powered by GMP 6.2.0
detected Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz
detected L1 = 32768 bytes, L2 = 8388608 bytes, CL = 64 bytes
measured cpu frequency ~= 3392.250200
using 1 random witnesses for Rabin-Miller PRP checks
. . .
cached 664579 primes. pmax = 9999991


>> sigma(28,1)
56
>> [/code][code]YAFU Version 2.0
Built with GCC 9
Using GMP-ECM 7.0.5-dev, Powered by GMP 6.2.0
Detected Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz
Detected L1 = 32768 bytes, L2 = 8388608 bytes, CL = 64 bytes
Using 1 random witness for Rabin-Miller PRP checks
Cached 664579 primes; max prime is 9999991
. . .
>> sigma(28,1)

ans = 1

>> [/code]

chris2be8 2021-05-26 15:52

[QUOTE=BudgieJane;579124]
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.[/QUOTE]

Assuming you don't have millions of them they should all go into factordb once you have fully factored them.

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

bsquared 2021-05-27 12:07

Version 2.03 is now available with recently reported bugs fixed. Thanks Stargate38, richs, and EdH!

EdH 2021-05-27 13:38

Great! Thanks for all your work!

richs 2021-05-28 15:12

Thanks, Ben. Your efforts are most appreciated!

charybdis 2021-05-30 12:53

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) i5-8500 CPU @ 3.00GHz



YAFU Version 2.02
Built with GCC 9
Using GMP-ECM 7.0.5-dev, Powered by GMP 6.2.1
Detected Intel(R) Core(TM) i5-8500 CPU @ 3.00GHz
Detected L1 = 32768 bytes, L2 = 9437184 bytes, CL = 64 bytes
Using 1 random witness for Rabin-Miller 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![/code]

Those remainders would suggest that YAFU is getting the sign of the constant term wrong. This is 2.02 but it doesn't look like anything relevant has changed in 2.03.

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.

EdH 2021-05-31 21:18

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
$[/code]which was easy to capture in a script.

YAFU 2... performs in this manner:[code]$ ./yafu "sigma(28,1)-28" -silent

ans = 28

$[/code]Although I can parse these three lines, it is easier not having to.

Thanks for all your development work.


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