# Dual{::ForwardDiff...} type error when JuMP tries autodiff User-defined Function

**URL:** <https://discourse.julialang.org/t/dual-forwarddiff-type-error-when-jump-tries-autodiff-user-defined-function/25639>\
**Category:** Optimization (Mathematical)\
**Created:** [June 25, 2019, 6:20am UTC](https://discourse.julialang.org/t/dual-forwarddiff-type-error-when-jump-tries-autodiff-user-defined-function/25639 "2019-06-25T06:20:46Z")\
**Posts on this page:** 1\
**Page:** 2

<div class="post-metadata">

**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [April 28, 2021, 9:26pm UTC](https://discourse.julialang.org/t/dual-forwarddiff-type-error-when-jump-tries-autodiff-user-defined-function/25639/21 "2021-04-28T21:26:08Z")

</div>

Please read the documentation: [Nonlinear Modeling · JuMP](https://jump.dev/JuMP.jl/stable/manual/nlp/#Automatic-differentiation)

You need to write generic code that is not restricted to `Float64`.

[Previous page](https://discourse.julialang.org/t/dual-forwarddiff-type-error-when-jump-tries-autodiff-user-defined-function/25639.md?page=1)