Yafu

[jasonp]

Originally Posted by bsquared

It seems many people have their own private collections of NFS statistics. Does anyone have a function relating composite size with combined poly score handy along with an idea of size of variations about that "normal line"?

I can't help with the latter, but currently the target minimum combined score for a poly to be reported is the result of exponential interpolation from the tables at the top of gnfs/poly/poly_skew.c in the Msieve source. The combined score is the last entry in each structure in the various lists.

The degree-5 numbers were cribbed from the pol51 readme within GGNFS, except that the cutoffs for C154-C155 were made a little more lenient. The speculation right now is that the targets for up to C140 were determined by experiment, and the targets for C140-155 were extrapolated, because empirically the larger cutoffs are somewhat more stringent than one would expect.

For degree 4 and 6, and the larger degree 5, the numbers were chosen strictly by experiment.

Of course that doesn't predict the maximum score we can reasonably expect.

[Andi47]

When I want to run nfs with yafu from the command line (i.e. not wihin yafu, but e.g. from aliqueit.exe), what do I have to type?

yafu -nfs -v -t <number of threads> <number to factorize> ?


edit: If I just type "yafu -v <number to factorize>": Is there a threshold where yafu decides whether to do qs or nfs?

[debrouxl]

Is there a threshold where yafu decides whether to do qs or nfs?

Yes, there is. yafu's QS implementation is fast, so the threshold can be slightly higher than with other QS implementations. The most suitable threshold for your computer can be adjusted by running tune() in yafu.

But I don't know the answer to your first question.

[bsquared]

Originally Posted by Andi47

When I want to run nfs with yafu from the command line (i.e. not wihin yafu, but e.g. from aliqueit.exe), what do I have to type?

yafu -nfs -v -t <number of threads> <number to factorize> ?


edit: If I just type "yafu -v <number to factorize>": Is there a threshold where yafu decides whether to do qs or nfs?

To run nfs do:
yafu "nfs(number)" -v -threads <number of threads>

To run a general purpose factoring routine do:
yafu "factor(number)" -v -threads <number of threads>

which will then do some pretesting with rho, p+/-1, and ecm before proceeding to nfs or siqs. I think the default cutoff is 95 digits. As debrouxl said, if you run tune() first, a more optimal cutoff will be determined. Tune takes 15-30min or so.

[LaurV]

hi bsqared, I think you did not see yet my post from the parallel thread (some mod could put the threads together?). sorry for bothering, just want to make sure you won't miss that post.

[BudgieJane]

I'm using the latest version downloaded for Windows from sourceforge.

I'm trying to factor a small number of 24 digits and I get this:

factoring 699887612373030702964813
using pretesting plan: normal

div: primes less than 10000
fmt: 1000000 iterations
rho: x^2 + 1, starting 1000 iterations on C24
rho: x^2 + 1, starting 1000 iterations on C18
rho: x^2 + 3, starting 1000 iterations on C18
rho: x^2 + 2, starting 1000 iterations on C18
matrix exhausted

What am I doing wrong?

Originally Posted by bsquared

It's one of those days...

Just posted another (relatively minor) bug fix. Also related to mpqs occasionally not finding factors.

Now at version 1.26.4

[bsquared]

Originally Posted by BudgieJane

I'm using the latest version downloaded for Windows from sourceforge.

I'm trying to factor a small number of 24 digits and I get this:

factoring 699887612373030702964813
using pretesting plan: normal

div: primes less than 10000
fmt: 1000000 iterations
rho: x^2 + 1, starting 1000 iterations on C24
rho: x^2 + 1, starting 1000 iterations on C18
rho: x^2 + 3, starting 1000 iterations on C18
rho: x^2 + 2, starting 1000 iterations on C18
matrix exhausted

What am I doing wrong?

I can't see that you're doing anything wrong, but neither am I able to reproduce the problem; everything works fine for me with your number and with all of the provided executables.

Is it a repeatable failure for you? If so, open the file session.log and post the two random numbers displayed in that file for one of the failed attempts.

[edit]
I take that back. It failed when I tried the 64k version. The 32k version seems to work (yafu-32k-Win32 or yafu-32k-x64). I'll look into it.

[Brian Gladman]

Both x64 versions of yafu from SVN work fine for me.

[bsquared]

Originally Posted by Brian Gladman

Both x64 versions of yafu from SVN work fine for me.

Yes, it seems to be a problem with only the 64k-Win32 version. I don't have a fix for the root cause (which seems to rarely involve a prime being flagged as dividing a sieve location when it really doesn't), but I've added an additional assertion which simply throws these invalid cases away.

Try out version 1.26.5 now on sourceforge.

-----
Factoring tiny numbers seems to be harder than big ones lately!

[Brian Gladman]

Ah, I thought it was an x64 issue. I have just done a minor fix of the Windows build but its not related to this issue (it corrects a false rebuild caused by a reference to a missing, no longer needed file). I have just tested all four versions (32k/64k win32/x64) from the SVN and all work fine for me.

[bsquared]

Originally Posted by Brian Gladman

Ah, I thought it was an x64 issue. I have just done a minor fix of the Windows build but its not related to this issue (it corrects a false rebuild caused by a reference to a missing, no longer needed file). I have just tested all four versions (32k/64k win32/x64) from the SVN and all work fine for me.

Great, thanks!