Sorry to bump up this old thread. I recently ran into very slow loops (slower than the equivalent ones in MATLAB) with 500k or so iterations which used cosh, cos/sin in each iteration. Replacing these by the Intel mkl vml routines lead to a 5X speed up. My processor only has avx2 instructions and I think if I try it on a processor with avx2-512 instruction set, this can be slashed even further. I use intel oneAPI under Linux.