# Adding (simple) user-defined functions causes significant slowdown in JuMP + Ipopt

**URL:** <https://discourse.julialang.org/t/adding-simple-user-defined-functions-causes-significant-slowdown-in-jump-ipopt/52971>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [January 7, 2021, 4:10am UTC](https://discourse.julialang.org/t/adding-simple-user-defined-functions-causes-significant-slowdown-in-jump-ipopt/52971 "2021-01-07T04:10:18Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**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:** [January 8, 2021, 3:59am UTC](https://discourse.julialang.org/t/adding-simple-user-defined-functions-causes-significant-slowdown-in-jump-ipopt/52971/4 "2021-01-08T03:59:56Z")

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I took a look into this. It’s the same reason as [Nonlinear Objective Function Splatting - #2 by odow](https://discourse.julialang.org/t/nonlinear-objective-function-splatting/51251/2).

If you have a multi-variate user-defined function, we don’t pass the hessian to Ipopt.

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