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jasonp 2007-01-12 04:53

Msieve 1.15
Now available. Major changes include:

- bug fixes, cleanups, memory use reduction and documentation for the NFS square root.

- an overhaul of the linear algebra code, that lets QS factorizations benefit from the much more sophisticated NFS matrix handling

- miscellaneous NFS fixes, and changes for powerpc and x86_64 systems

I'm reasonably confident that NFS factorizations will succeed by default now, although they will proceed much too slowly for my taste :)

The next version will probably take a few months; I want to overhaul the NFS polynomial selector and fold in the latest algorithmic ideas, some of which have never been implemented before.

Happy factoring,

jasonp 2007-01-17 05:51

Msieve 1.16
A few internal changes here, as well as a fix for a silly bug in the multiple precision library (that was causing NFS polynomial selection to quit early).

I've started looking at the polynomials produced by the pol5 code in GGNFS, and compared to the ones produced by msieve the total yield of optimized polynomials should be about 2.2x higher. The reason it's so much more than that in practice is that the sieving region is the wrong shape.

Happy factoring,

jasonp 2007-03-13 02:46

Msieve v1.17
Now available. Highlights include:

- Much better NFS filtering. The current implementation will automatically determine the right matrix size given the current dataset and the level of sparsity desired; it also includes several algorithmic enhancements

- Bug fixes all over the NFS code, some quite serious

- The beginnings of a skewed NFS polynomial selector (currently turned off)

- Pollard Rho factorization is performed automatically. Factorizations with many small factors will complete much faster now

- Recursive factorization has been pushed into the library. Now all factors found are reported at once, in increasing order

This version should have all the machinery in place to complete factorizations started by GGNFS (thanks to Greg Childers for providing a sample SNFS factorization to train the library on). My limited experience here is that msieve uses much less memory (~6x less) to construct the matrix, and the resulting matrix is somewhat larger but much lighter than GGNFS run on the same set of relations.

I haven't been able to reproduce the slowdowns reported when using gcc 4.1.1, but I only managed to try on x64

Happy factoring,

jasonp 2007-04-05 05:09

Msieve v1.18
Now available. Major changes include:

- more automatic tuning of NFS filtering, plus a new postprocessing phase for the merged relations
- bug fixes all over the NFS code
- a fix for a nasty bug in the long division routine

Priorities for the near future, in approximately the order I want to do them, are:

- add support for 'a' values > [tex]2^{32}[/tex] in NFS relations (this should finally allow msieve to act as a drop-in postprocessor for GGNFS)
- add cache blocking to the linear algebra
- work on a skewed polynomial selector

Happy factoring,

jasonp 2007-04-17 14:27

Msieve v1.19
Now available. Highlights include:

- a major overhaul of the linear algebra. I've added cache blocking, use of MMX registers on 32-bit x86 systems, and a fix (I hope) for the trouble people have been seeing with the linear algebra restarting. This version should handle the linear algebra for large NFS jobs 4-5x faster than v1.18!

- changed the format of the factor base file. The new format makes all of the parameters used in an NFS run manually configurable. Restarting an existing NFS job with this msieve version will convert to the new format automatically

- more bug fixes all over

The next version will probably have improvements to the NFS polynomial selection, documenting of the NFS filter phase, and some QS work too (Bill Hart has pointed out the need for more automatic tuning of the QS sieving).

Happy factoring,

jasonp 2007-05-02 04:23

Msieve v1.20
Now available. Highlights include:

- support for NFS relations with 64-bit 'a' values. This should let msieve finish any factorization started with GGNFS

- a lot of QS changes. The biggest is that the core sieving code is now compiled over and over again with different optimization flags and preprocessor directives, and the best version of the sieving code is chosen at runtime. This is basically a do-it-yourself 'fat binary' that should achieve increased performance across a range of processors (though the difference is not that large, 5-10% is typical with smaller factorizations seeing the biggest gains)

- lots of little changes in the NFS postprocessing. This includes bug fixes and documentation of the NFS filtering

The QS changes are still in progress, and there's a lot of potential for more tuning, especially on low-memory machines. I hope to do some of that tuning for the next version, and finally get around to improved NFS polynomial selection.

Happy factoring,

jasonp 2007-05-12 02:48

Msieve v1.21
Now available. Highlights include:

- Much improved NFS filtering, driven by the pounding everyone here is giving the NFS code

- updated MSVC build and MSVC versions of the assembly code, both courtesy of Brian Gladman

- fixes and documentation all over

The next version will hopefully deal with lingering problems several users are reporting, and will hopefully include multithreaded linear algebra.

Happy factoring,

PS: @smh:
Fri May 11 10:52:36 2007 prp49 factor: 6214371966272720891412679817612071803187468972909
Fri May 11 10:52:40 2007 prp62 factor: 13602227447995293360238994329010469074018220326044935134602609

jasonp 2007-05-27 06:01

Msieve v1.22
Now available. Highlights include:

- multithreaded linear algebra for both QS and NFS. This is still sort of a work in progress, and the speedup with two threads is far short of 2x, but it's very cool to solve a matrix for a C211 in just 28 hours.

- the demo binary now will read in numbers in octal or hex format

- bug fixes all over

Brian Gladman is hard at work removing the dependency on the Gnu Scientific Library, and hopefully I'll be able to merge that in for the next version. Other than that, I want to try some more really big NFS jobs, and if nothing unusual shows up I'll go back to NFS polynomial selection.

Happy factoring,

jasonp 2007-06-03 23:01

Msieve v1.23
Now available. This is an interim release to get some linear algebra and NFS filtering fixes out, that seem to be necessary to complete big NFS jobs using msieve.

The plan for the next version is the same as before. Happy factoring,

jasonp 2007-06-25 05:14

Msieve v1.24
Now available. Highlights include:

- removed the dependency on the Gnu Scientific Library. It was a fair amount of work, and lots of credit is due to Brian Gladman for helping out. If anybody wants high-performance numerical integration and polynomial rootfinding code that's free and not a mess, it's in there now.

- tweaked the NFS filtering to handle some of the hard jobs people have tried

- several NFS bug fixes

The removal of GSL is the first step in the long-awaited overhaul of the NFS polynomial selection. That's my top priority now, so hopefully the next version will see some meaningful progress in that regard.

Happy factoring,

jasonp 2007-06-28 03:44

Msieve v1.25
This is an emergency release that fixes a QS problem that affects the core sieving loops for some processors (antiroach, it's the reason you get a seg fault)


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