# How to use ForwardDiff.GradientConfig for multiple input functions while calculating gradients in parallel

**URL:** https://discourse.julialang.org/t/how-to-use-forwarddiff-gradientconfig-for-multiple-input-functions-while-calculating-gradients-in-parallel/30370
**Category:** New to Julia
**Created:** [October 27, 2019, 6:35pm UTC](https://discourse.julialang.org/t/how-to-use-forwarddiff-gradientconfig-for-multiple-input-functions-while-calculating-gradients-in-parallel/30370 "2019-10-27T18:35:50Z")
**Posts on this page:** 1
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### Author: ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [October 28, 2019, 4:54am UTC](https://discourse.julialang.org/t/how-to-use-forwarddiff-gradientconfig-for-multiple-input-functions-while-calculating-gradients-in-parallel/30370/2 "2019-10-28T04:54:46Z")

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I am not sure if I understood your question, but `ForwardDiff.GradientConfig` is not used to select dimensions for differentiation, but for selecting things like chunk size:

[http://www.juliadiff.org/ForwardDiff.jl/stable/user/advanced.html#Configuring-Chunk-Size-1](http://www.juliadiff.org/ForwardDiff.jl/stable/user/advanced.html#Configuring-Chunk-Size-1)

If you want derivatives along a subset of the input, use a closure.

If you need more help, please post a self-contained MWE.

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