Re: [Haskell-cafe] blas bindings, why are they so much slower the C?

On Tue, Jun 17, 2008 at 9:00 PM, Anatoly Yakovenko wrote:

here is the C:

#include #include

int main() { int size = 1024; int ii = 0; double* v1 = malloc(sizeof(double) * (size)); double* v2 = malloc(sizeof(double) * (size)); for(ii = 0; ii < size*size; ++ii) { double _dd = cblas_ddot(0, v1, size, v2, size); } free(v1); free(v2); }

Your C compiler sees that you're not using the result of cblas_ddot, so it doesn't even bother to call it. That loop never gets run. All your program does at runtime is call malloc and free twice, which is very fast :-)