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Old 2019-10-21, 15:26   #1
storm5510
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Aug 2009

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Default Just a few problems.

Learning YAFU has been an ongoing learning project.

So, if I run this:

Code:
yafu.exe "nfs(2^2273-1)" -v
Below is the response:

Code:
10/21/19 11:11:33 v1.35-beta @ DESKTOP-CBJIQ5R, System/Build Info: 
Using GMP-ECM 7.0.4, Powered by GMP 6.1.2
detected Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz
detected L1 = 32768 bytes, L2 = 8388608 bytes, CL = 64 bytes
measured cpu frequency ~= 3633.658040
using 1 random witnesses for Rabin-Miller PRP checks

===============================================================
======= Welcome to YAFU (Yet Another Factoring Utility) =======
=======             bbuhrow@gmail.com                   =======
=======     Type help at any time, or quit to quit      =======
===============================================================
cached 78498 primes. pmax = 999983


>> nfs: checking for job file - job file found, testing for matching input
nfs: number in job file matches input
nfs: checking for data file
nfs: no data file found
nfs: commencing nfs on c685: 1742529520249056365512311353133210194868002470362733988718715702982049553878204974098095879957046832133411116918454362118733432444115935018714466786957605746348649192788820800696196515419189104683104957187774528626675040280292359797245618173808073285037449211441338460459359488199888816259777611053192701961659180955402379577469159828320928237838306141193366024320020020406550115646199896773300050762697536767502815384675215990944010597050121839365705495260405711680625463166940749616744059475821932476870841353759757688198160654803105173484222505416851352655856542995917645077182797114155482006005394666665993761527547105656127708028861905978284863688229753943906920953645204758331391
nfs: resumesieve; last_spq = 0, nfs_phases = 0
nfs: parsed lpbr = 26, lpba = 26
nfs: creating ggnfs job parameters for input of size 685
Error: m is not a common root of the polynomials:
c0: -135941441485299623821377975
c1: 18442770087320538690649
c2: 1144416907608563521
c3: -42817211718353
c4: -347973258
c5: 16632
Y0: -1237038659848269396424
Y1: 551747168957
n: 1742529520249056365512311353133210194868002470362733988718715702982049553878204974098095879957046832133411116918454362118733432444115935018714466786957605746348649192788820800696196515419189104683104957187774528626675040280292359797245618173808073285037449211441338460459359488199888816259777611053192701961659180955402379577469159828320928237838306141193366024320020020406550115646199896773300050762697536767502815384675215990944010597050121839365705495260405711680625463166940749616744059475821932476870841353nfs: continuing with sieving - could not determine last special q; using default startq
nfs: commencing algebraic side lattice sieving over range: 1600000 - 1920000
nfs: could not open output file, possibly bad path to siever
fopen error: No such file or directory
could not open rels0.dat for reading
The bold items are indicative of something being missing or out of place. I am not sure what is going on?
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Old 2019-10-21, 15:46   #2
chris2be8
 
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The critical message is:
Quote:
nfs: commencing nfs on c685: 174252952024905636551...
Factoring a 685 digit number by GNFS (or SNFS) is an absolutely hopeless effort. It looks as if polynomial selection has got confused and generated a polynomial for a smaller number, possibly the input truncated somehow. But there's no way that number could be factored by NFS before the heat death of the universe.

Try a few smaller numbers. Eg RSA100, RSA110, RSA120, ... Those should finish in a reasonable time.

Numbers with a simple formula should be done with SNFS if possible, it's usually much faster than GNFS.

Chris
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Old 2019-10-21, 16:22   #3
bsquared
 
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I admit I am not even sure how you got as far as you did. This is what I saw:

Code:
nfs: checking for job file - job file found, testing for matching input
nfs: number in job file does not match input
nfs: checking for poly file - no poly file found
nfs: commencing nfs on c685: 1742529520249056365512311353133210194868002470362733988718715702982049553878204974098095879957046832133411116918454362118733432444115935018714466786957605746348649192788820800696196515419189104683104957187774528626675040280292359797245618173808073285037449211441338460459359488199888816259777611053192701961659180955402379577469159828320928237838306141193366024320020020406550115646199896773300050762697536767502815384675215990944010597050121839365705495260405711680625463166940749616744059475821932476870841353759757688198160654803105173484222505416851352655856542995917645077182797114155482006005394666665993761527547105656127708028861905978284863688229753943906920953645204758331391
nfs: n is too large for snfs, skipping snfs poly select
nfs: setting deadline of 1080000 seconds
nfs: commencing polynomial search over range: 8192 - 8442
commencing number field sieve (338-digit input)
commencing number field sieve polynomial selection
polynomial degree: 6
max stage 1 norm: 0.00e+000
max stage 2 norm: 0.00e+000
min E-value: 0.00e+000
poly select deadline: 0
error: stage 1 bound not provided
Suffice to say: yafu was not designed to factor inputs this large by nfs. As usual I have not built in sufficient sanity checking prior to trying. In this case the input gets truncated when invoking msieve. Actually, what probably happens is the too-large input string goes and corrupts other data fields in the msieve object.

Anyway, try factoring something (much) smaller.
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Old 2019-10-21, 22:25   #4
storm5510
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Quote:
Originally Posted by bsquared View Post
I admit I am not even sure how you got as far as you did. This is what I saw:

Code:
nfs: checking for job file - job file found, testing for matching input
nfs: number in job file does not match input
nfs: checking for poly file - no poly file found
nfs: commencing nfs on c685: 1742529520249056365512311353133210194868002470362733988718715702982049553878204974098095879957046832133411116918454362118733432444115935018714466786957605746348649192788820800696196515419189104683104957187774528626675040280292359797245618173808073285037449211441338460459359488199888816259777611053192701961659180955402379577469159828320928237838306141193366024320020020406550115646199896773300050762697536767502815384675215990944010597050121839365705495260405711680625463166940749616744059475821932476870841353759757688198160654803105173484222505416851352655856542995917645077182797114155482006005394666665993761527547105656127708028861905978284863688229753943906920953645204758331391
nfs: n is too large for snfs, skipping snfs poly select
nfs: setting deadline of 1080000 seconds
nfs: commencing polynomial search over range: 8192 - 8442
commencing number field sieve (338-digit input)
commencing number field sieve polynomial selection
polynomial degree: 6
max stage 1 norm: 0.00e+000
max stage 2 norm: 0.00e+000
min E-value: 0.00e+000
poly select deadline: 0
error: stage 1 bound not provided
Suffice to say: yafu was not designed to factor inputs this large by nfs. As usual I have not built in sufficient sanity checking prior to trying. In this case the input gets truncated when invoking msieve. Actually, what probably happens is the too-large input string goes and corrupts other data fields in the msieve object.

Anyway, try factoring something (much) smaller.
I have tried factor(). If I use the numeric form, it does not produce any errors that I have seen. However, it has the appearance of taking a very long time.

Either way, this was all simply an experiment on my part and perhaps the chance of learning something new. It was really not all that important.

Thank you for the replies.
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