# My julia code is somehow much slower than the matlab code

**URL:** <https://discourse.julialang.org/t/my-julia-code-is-somehow-much-slower-than-the-matlab-code/91792>\
**Category:** New to Julia\
**Tags:** question, performance, matlab\
**Created:** [December 17, 2022, 9:01pm UTC](https://discourse.julialang.org/t/my-julia-code-is-somehow-much-slower-than-the-matlab-code/91792 "2022-12-17T21:01:15Z")\
**Posts on this page:** 1\
**Showing post:** 23

<div class="post-metadata">

**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [December 19, 2022, 1:09pm UTC](https://discourse.julialang.org/t/my-julia-code-is-somehow-much-slower-than-the-matlab-code/91792/23 "2022-12-19T13:09:41Z")

</div>

> [@Wooheon](#):
>
> ` V=zeros(n_k,n_z);i=1;k_index=Array{CartesianIndex{3}, 3}`

If I’m reading this line correctly, you’re setting `k_index` equal to a datatype and then in the hot loop you’re changing its value to an _instance_ of that type.

---

_[View the full topic](https://discourse.julialang.org/t/my-julia-code-is-somehow-much-slower-than-the-matlab-code/91792)._