Instructions to install GMP-ECM: 0) you first need to install the GNU MP (GMP) library. GNU MP is available from . Remark: GNU MP is already installed in most Linux distributions. However it is often an old version, moreover without processor-specific optimizations. If you care about efficiency, be sure to install the latest version of GNU MP (6.3.0 as of June 2024), and to compile it for your particular processor. Warning: make sure you have only one version of GMP installed on your system at a given time. Frequently, after compiling GMP from source and installing it without removing the distribution's GMP package, later attempts to build software that uses GMP find the GMP header file from the distribution's GMP package and the library from the newly compiled GMP (or vice versa). GMP-ECM tries to detect this by comparing the version number from header and library; if this test fails, you should remove the obsolete GMP installation. 1) check your configuration with: $ ./configure The configure script accepts several options (see ./configure --help). In particular you can specify the GMP installation directory with: $ ./configure --with-gmp= where /include contains the header file gmp.h, and /lib contains the static or dynamic libraries (libgmp.a, libgmp.so, libgmp.lib). To compile the GMP-ECM library as a shared library, use the --enable-shared parameter for ./configure. Building a shared library is disabled by default. Note: the configure script will first search for a static GMP library, which makes GMP-ECM more efficient. When only a dynamic library is available, make sure to correctly set your dynamic libraries search path (LD_LIBRARY_PATH on Unix systems), otherwise the configure script may fail. Warning: it is recommended to use the same compiler and options as those used to compile GMP, otherwise the compilation may fail, or you may get poor performance. In the GMP build directory, simply type: $ egrep -w '(CC|CFLAGS)' config.log to see which compiler and options were used to build GMP. For example on a Sparc v9 you may have to type: $ ./configure CC=cc CFLAGS="-fast -fns=no -fsimple=1 -xarch=v9" Note 2: On x86, x86-64, and 64 bit PowerPC systems, using GMP-ECM's own modular multiplication code usually gives better performance than the GMP-based functions. On these systems, configure enables it by default. If the system is not identified correctly, you can enable it by adding the command line parameter "--enable-asm-redc" to configure. To disable it, add "--disable-asm-redc". On 32-bit x86 systems that have SSE2 (e.g., Pentium 4, some Celeron, some Sempron, Via C7), use of SSE2 instructions in stage 2 of P-1, P+1, and ECM is enabled by default. You can enable it manually by adding the command line parameter "--enable-sse2" and disable it by adding "--disable-sse2" to ./configure. The SSE2 code is not used in 64-bit builds, regardless of these parameters. Note 3: If you want to use George Woltman's GWNUM library for speeding up factoring, detailed instructions for building and linking to the gwnum.a library may be found in the INSTALL-gwnum file. 2) compile the program with: $ make This will create the 'libecm.a' library, the 'libecm.so' shared library if --enable-shared was used, the 'ecm' binary file, the 'ecmfactor' binary file (sample use of libecm.a), and 'tune', a tuning program. 3) to check that the program works correctly, type: $ make check This will run several tests for P+1, P-1, ECM. These tests take a few minutes. It should normally end with the "TOTAL" count equal to the "PASS" count, with the remaining counts all zero. 4) (optional) to tune GMP-ECM, simply type: $ make ecm-params; make See also README ("How to get the best of GMP-ECM?"). Note: if your machine has not enough memory for the tune program, you can run it manually with ./tune -max_log2_len 16 for example (the default is 18). 5) (optional) you can then install the ecm binary and its man page: $ make install By default, installation will be done in /usr/local. You can change with the --prefix option of configure at step 1: $ ./configure --prefix= The ecm binary will go in /bin, its man page in /share/man/man1, the ecm library in /lib, and the corresponding header file in /include. You can also do "make uninstall" to remove those files. 6) (optional) When using -param 0, it is now possible to speed up Stage 1 by 4 to 5 percent. This requires the user to generate a file, called "Lchain_codes.dat", using a program (LucasChainGen) included with this release. For details on how to build and run LucasChainGen, see the README file in the LucasChainGenerator folder. Once the Lchain_codes.dat file is available, and it is moved to the ecm run directory, ecm stage 1 with '-param 0' set will use the file to generate a Lucas chain for every prime less than or equal to min( B1, file limit), and revert to use 'prac' if 'end-of-file' is reached. ============================================================================ To install GMP-ECM with support of NVIDIA Graphics Cards: see README.gpu ============================================================================ Known problems: see https://gitlab.inria.fr/zimmerma/ecm/-/issues ============================================================================ For OPAM users: there is an OPAM package for GMP-ECM which is tested on MacOS (including Apple silicon), many Linux variants and Windows (MinGW with cygwin build host). See https://github.com/ocaml/opam-repository/pull/20105 (contributed by Michael Soegtrop). For Windows users: Windows users have two options for building GMP-ECM: (a) the use of a number of Unix on Windows environments, or (b) the use of Microsoft Visual Studio C/C++ 2008. The former is described here while the latter is described in the readme.txt file within the build.vc10 subdirectory. (a) For Windows users with a Unix-like environment: Before you can compile GMP-ECM, you will need a compiler. Several suitable compilers are freely available, for example as part of MinGW, CygWin and Microsoft's Services for Unix (SFU). We recommend MinGW as it is a smaller download than the others and generates binaries that run on any Windows system, even if they don't have MinGW installed themselves. Step-by-step instructions, courtesy of Jes Hansen: 1) Download the current MinGW from http://prdownloads.sf.net/mingw/MinGW-3.1.0-1.exe?download and MSYS from http://prdownloads.sf.net/mingw/MSYS-1.0.10.exe?download 2) Create a folder, for example C:\GNU, and install MinGW (execute the MinGW-3.1.0-1.exe file) into C:\GNU\MinGW 3) Install MSYS (execute the MSYS-1.0.10.exe file) into C:\GNU\msys Now you get an icon on the desktop where you can start the MinSys. Do this, because is creates your home folder. Then exit it again. 4) Download the latest version of GMP in .tar.gz format from http://gmplib.org/ and place it in your newly created home folder. The home folder is in C:\GNU\msys\home and has the same name as your Windows login name. 5) Download GMP-ECM (if you do not have it already) from https://gitlab.inria.fr/zimmerma/ecm and place it in your home folder as well. 6) Start the MinSys up again from the desktop and type tar -xvzf gmp-6.1.0.tar.gz cd gmp-6.1.0 ./configure make install cd ~ 7) You are back in your home directory. Now type tar -xvzf ecm-x.y.z.tar.gz cd ecm-x.y.z ./configure --with-gmp=/usr/local make 8) Four executables should have appeared. The main application is ecm.exe, which can be run from the Windows command line. ============================================================================ In case of a problem, report it to us, with: - the output of the config.log file - the versions of GMP-ECM and GMP used (first output line), for example: GMP-ECM x.y.z [configured with GMP u.v.w, --enable-asm-redc] [P+1] - the detailed input enabling us to reproduce the problem, for example: $ echo 328006342451 | ./ecm -pp1 -x0 5 120 7043 - the output you get. Then send your bug report at . This is a public list, with archives available at .