[Ecm-discuss] GMP-ECM 7.0

paul zimmermann Paul.Zimmermann at inria.fr
Mar 15 Mar 12:00:52 CET 2016

       Dear all,

almost 3 years after the last release, GMP-ECM 7.0 is out:


Changes between GMP-ECM 6.4.4 and GMP-ECM 7.0:

* GMP-ECM is now thread-safe. In particular the "ecmfactor" binary can be
  called with say -t 17 to use 17 threads.
* Added GPU code for Step 1 (command-line option -gpu).
* Command-line option -param allows to choose the parametrization (valid values
  are 0, 1, 2, 3). Command-line option -sigma allows to choose the parameter.
  "-sigma i:s" is a shortcut to "-param i -sigma s". Use -param 0 to get
  historical Suyama parametrization.
* The batch mode is now chosen with -param command-line option.
  The default parametrization depends on other command-line options.
* For P-1 stage 2, by default the NTT code is always used.
* Speedup in stage 2 with -no-ntt
* New primality proving code with APRCL (contributed by David Cleaver)
  with --enable-aprcl (default=yes)
* Removed some options that were unused or not tested (-n, -nn, -ve, -cofdec,
* The configure --enable-shellcmd option was removed, and also the
  --enable-memory-debug configure option (now obsolete with valgrind).
* The -b options was removed (breadth-first mode)
* Improved source coverage (92.7% of source code lines)

I would like to thank in particular Cyril Bouvier who contributed the GPU code
and helped to the new parametrizations, and David Cleaver who contributed the
primality proving code, and helped to increase the source coverage.

The curves used by default by GMP-ECM 7 have a slightly smaller probability of
success (see http://www.loria.fr/~zimmerma/records/ecm/params.html) but the
speed-up in stage 1 more that compensates that, thus it is recommended to use
those defaults curves. If you want to use the same curves as previous versions
of GMP-ECM, use -param 0.

Happy factoring!

PS: no support will be provided any more for GMP-ECM 6, please switch as soon as
possible to GMP-ECM 7.

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