Openblas is an optimized blas library based on gotoblas2 1.13 bsd version.

unlike atlas, openblas provides a multiple architecture library.

all kernel will be included in the library and dynamically switched to the best architecture at run time (only on x86 arches).

for more information on how to rebuild locally openblas, see the section: "building optimized openblas packages on your arch" in readme.debian