# Why does explicit declaration of ::INT save 40% runtime?

**URL:** <https://discourse.julialang.org/t/why-does-explicit-declaration-of-int-save-40-runtime/127575>\
**Category:** Performance\
**Tags:** performance\
**Created:** [March 31, 2025, 9:25pm UTC](https://discourse.julialang.org/t/why-does-explicit-declaration-of-int-save-40-runtime/127575 "2025-03-31T21:25:41Z")\
**Posts on this page:** 1\
**Showing post:** 16

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**Author:** ![uwestoehr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/uwestoehr/32/216201_2.png) [@uwestoehr](https://discourse.julialang.org/u/uwestoehr)\
**Post date:** [April 2, 2025, 12:49am UTC](https://discourse.julialang.org/t/why-does-explicit-declaration-of-int-save-40-runtime/127575/16 "2025-04-02T00:49:21Z")

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> [@mikmoore](#):
>
> or `Vector{SVector{dimension, Float64}}` where `SVector` comes from StaticArrays.jl.

I tried this but there is a general issue with Julia, I opened a new thread for it:

> [@About reproducibility of Julia program run times](http://discourse.julialang.org/t/about-reproducibility-of-julia-program-run-times/127613):
>
> I have a general issue with Julia. I know there is no solution but something should be done because as it is collaborative work is hard: The runtime of Julia programs is not stable. I don’t see fluctuations in the range of 10% but of 100%. StaticArrays is a good example why I struggle with Julia (I come from C++ and also Lazarus). Take for example this code: matrix = rand(Float64, 1500, 2) @elapsed sDataMatrix= SMatrix{1500, 2}(matrix) This takes here 3.22 seconds. But only at the first ru…

Regarding SVector the run time is not stable, therefore it is no option for me. Sometimes it is unbeatably fast, but sometimes slow.

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