ecm: Elliptic curve method for integer factorization#

Description#

GMP-ECM - Elliptic Curve Method for Integer Factorization

LGPL V3+

GMP-ECM comes with a self-tuning feature; we could support that as an option ($SAGE_TUNE_*=yes) in the future.
ECM currently does not (by itself) use the CC and CFLAGS settings from ‘gmp.h’ since we pass (other) options in CFLAGS, and CC is set by Sage and might got set by the user. We now at least partially fix that such that “optimized” code generation options (‘-mcpu=…’, ‘-mtune=…’) are used by gcc. Of course a user can also manually enable them by setting the “global” CFLAGS to e.g. ‘-march=native’ on x86[_64] systems, or ‘-mcpu=…’ and ‘-mtune=…’ on other architectures where “native” isn’t supported. Note that this doesn’t affect the packages’ selection of processor- specific optimized [assembly] code. ‘spkg-install’ already reads the settings from Sage’s and also a system-wide GMP now, but doesn’t (yet) use all of them. If SAGE_FAT_BINARY=”yes”, we should avoid too specific settings of “-mcpu=…”, and perhaps pass a more generic “–host=…” to ‘configure’.
We currently work around a linker bug on MacOS X 10.5 PPC (with GCC 4.2.1) which breaks ‘configure’ if debug symbols are enabled. This *might* get fixed in later upstream releases.
We could save some space by removing the src/build.vc10/ directory which isn’t used in Sage. (It gets probably more worth in case also directories / files for later versions of Microsoft Visual C get added.)

standard

package-version.txt:

7.0.5

conda-forge

$ conda install ecm

Debian/Ubuntu

$ sudo apt-get install gmp-ecm libecm-dev

Fedora/Redhat/CentOS

$ sudo yum install gmp-ecm gmp-ecm-devel

FreeBSD

$ sudo pkg install math/gmp-ecm

MacPorts

$ sudo port install gmp-ecm

Nixpkgs

$ nix-env --install ecm

Void Linux

$ sudo xbps-install ecm-devel

If the system package is installed, ./configure will check if it can be used.