# Different Float64 sum on different architectures

**URL:** <https://discourse.julialang.org/t/different-float64-sum-on-different-architectures/46949>\
**Category:** General Usage\
**Created:** [September 20, 2020, 9:16am UTC](https://discourse.julialang.org/t/different-float64-sum-on-different-architectures/46949 "2020-09-20T09:16:26Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![danielw2904](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/danielw2904/32/10890_2.png) [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Post date:** [September 20, 2020, 10:44am UTC](https://discourse.julialang.org/t/different-float64-sum-on-different-architectures/46949/3 "2020-09-20T10:44:36Z")

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See here for a simple example:

> [@Different inner product if vector type is not set](https://discourse.julialang.org/t/different-inner-product-if-vector-type-is-not-set/35359/8):
>
> I think you do, but you may be surprised to know that floating point addition is not associative (due to, essentially, rounding). julia\> @show (-1e30+1e30)+1.0 -1e30+(1e30+1.0); (-1.0e30 + 1.0e30) + 1.0 = 1.0 -1.0e30 + (1.0e30 + 1.0) = 0.0

Basically, summation is not associative and there is no guarantee for the order of execution of the sum.

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