> I want to use "dgemm" the argument of dgemm is different in GSL?
Are you using cblas_dgemm? If so, the API is the standard CBLAS API shown at http://www.gnu.org/software/gsl/manual/html_node/Level-3-CBLAS-Functions.html#Level-3-CBLAS-Functions. Presumably if you're using MKL's CBLAS interface (guessing from your subject), the API should be the same. - Rhys
