I don't know anything about Fortran and haven't examined the code, but this comment on the blog to Fernando Perez seems to have a plausible explanation: > The

I don't know anything about Fortran and haven't examined the code, but this comment on the blog to Fernando Perez seems to have a plausible explanation: > The C/Python-Code has its inner loop cache friendly, while the Fortran code has a cache unfriendly inner loop (because X(i,k) and X(i,k+1) are far away in memory). -- TS