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| -rw-r--r-- | INSTALL.txt | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/INSTALL.txt b/INSTALL.txt index f8ef7c0c1..7b33b6220 100644 --- a/INSTALL.txt +++ b/INSTALL.txt @@ -29,6 +29,36 @@ Building NumPy requires the following software installed: __ http://www.python.org +Fortran ABI mismatch +==================== + +The two most popular open source fortran compilers are g77 and gfortran. +Unfortunately, they are not ABI compatible, which means that concretely you +should avoid mixing libraries built with one with another. In particular, if +your blas/lapack/atlas is built with g77, you *must* use g77 when building +numpy and scipy; on the contrary, if your atlas is built with gfortran, you +*must* build numpy/scipy with gfortran. + +Choosing the fortran compiler +----------------------------- + +To build with g77: + + python setup.py build --fcompiler=gnu + +To build with gfortran: + + python setup.py build --fcompiler=gnu95 + +How to check the ABI of blas/lapack/atlas +----------------------------------------- + +One relatively simple and reliable way to check for the compiler used to build +a library is to use ldd on the library. If libg2c.so is a dependency, this +means that g77 has been used. If libgfortran.so is a a dependency, gfortran has +been used. If both are dependencies, this means both have been used, which is +almost always a very bad idea. + Building with ATLAS support =========================== |