Building ecmpi

mkdir builddir
cd builddir
cmake ..
make

Dependencies

To compile, ecmpi needs MPI, GMP (gmp.h and libgmp) and GMP-ECM (ecm.h and libecm). The version of GMP-ECM must be at least 7.0.

The MPI library is detected with the CMake's module FindMPI.

By default, CMake will look for GMP and GMP-ECM in the system directories and then in the directories listed by the following environment variables:

• PATH and INCLUDE for header;
• PATH and LIB for library.

This behaviour can be overriden with the following environment variables:

• GMP_INCDIR (to specify a directory containing gmp.h), GMP_LIBDIR (to specify a directory containing the GMP library) and GMP (to specify a source or install directory of GMP);
• ECM_INCDIR (to specify a directory containing ecm.h), ECM_LIBDIR (to specify a directory containing the GMP-ECM library) and ECM (to specify a source or install directory of GMP-ECM).

For example, you can replace the cmake .. line in the above instructions by the following one:

GMP=$HOME ECM_INCDIR=/tmp/include ECM_LIBDIR=/tmp/lib cmake ..

Running ecmpi

Example:

mpiexec -H localhost,localhost ./ecmpi -N 221 -nb 16 -B1 10

This command line launches two MPI processes on localhost to try to factor 221 using 16 curves with B1=10.

The list of command-line parameters can be obtained by running the ecmpi binary without argument.