The ATLAS (Automatically Tuned Linear Algebra Software) project is an ongoing research effort focusing on applying empirical techniques in order to provide portable performance. At present, it provides C and Fortran77 interfaces to a portably efficient BLAS implementation, as well as a few routines from LAPACK. If you use blas, you can simply change flags when linking, from -lblas to -lf77blas -latlas (order is important). A few routines from LAPACK are merged into one library as libalapack. It requres both C and Fortran77 interfaces, and thus that link line would be: -lalapack -lf77blas -lcblas -latlas -lg2c -lm . Other choice of CC and CFLAGS are *NOT* recommended. They are already optimized for this platform and automatically searched.