# Simple summation 8x slower than in Julia

**URL:** <https://fortran-lang.discourse.group/t/simple-summation-8x-slower-than-in-julia/1171>\
**Category:** Uncategorized\
**Created:** [May 7, 2021, 8:47pm UTC](https://fortran-lang.discourse.group/t/simple-summation-8x-slower-than-in-julia/1171 "2021-05-07T20:47:48Z")\
**Posts on this page:** 1\
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**Author:** ![mohoree](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@mohoree](https://fortran-lang.discourse.group/u/mohoree)\
**Post date:** [November 24, 2021, 9:34am UTC](https://fortran-lang.discourse.group/t/simple-summation-8x-slower-than-in-julia/1171/98 "2021-11-24T09:34:05Z")

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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.

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