# Evaluate gradient (backpropagation) on a user defined type

**URL:** <https://discourse.julialang.org/t/evaluate-gradient-backpropagation-on-a-user-defined-type/74434>\
**Category:** Machine Learning\
**Created:** [January 11, 2022, 9:30pm UTC](https://discourse.julialang.org/t/evaluate-gradient-backpropagation-on-a-user-defined-type/74434 "2022-01-11T21:30:51Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![shiroghost](https://avatars.discourse-cdn.com/v4/letter/s/b9e5f3/32.png) [@shiroghost](https://discourse.julialang.org/u/shiroghost)\
**Post date:** [January 19, 2022, 6:20pm UTC](https://discourse.julialang.org/t/evaluate-gradient-backpropagation-on-a-user-defined-type/74434/5 "2022-01-19T18:20:02Z")

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Many thanks,

I have managed `Zygote.jl` to work, but unfortunately is much slower than `ReverseDiff.jl` (even for simple real-valued functions). I have open a new question about this, to see if I am missing anything ([Zygote terribly slow. What am I doing wrong?](https://discourse.julialang.org/t/zygote-terribly-slow-what-am-i-doing-wrong/74877)).

Thanks!

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