Section: Software

GMP-ECM

Participants : Cyril Bouvier, Paul Zimmermann [contact] .

GMP-ECM is a program to factor integers using the Elliptic Curve Method. Its efficiency comes both from the use of the GMP library, and from the implementation of state-of-the-art algorithms. GMP-ECM contains a library (libecm ) in addition to the binary program (ecm ). The binary program is distributed under Gpl , while the library is distributed under Lgpl , to allow its integration into other non-Gpl software. The Magma computational number theory software and the Sage computer algebra system both use libecm .

In January 2012, a new version 6.4 was released, followed by 6.4.1 and 6.4.2 in March, and 6.4.3 in June. Apart from bug fixes, and the fact that GMP-ECM is now distributed under the LGPL version 3, those new releases provide a new -batch option with faster Stage 1 code, and an improved tuning mechanism.

In February, Paul Leyland found a 43-digit factor using the GPU implementation of Stage 1 written by C. Bouvier, and in August, a new record prime of 79 digits was found by Sam Wagstaff (Purdue University) using GMP-ECM .