# Equality Constraint format in NLopt

**URL:** <https://discourse.julialang.org/t/equality-constraint-format-in-nlopt/24491>\
**Category:** New to Julia\
**Tags:** optimization\
**Created:** [May 22, 2019, 7:22pm UTC](https://discourse.julialang.org/t/equality-constraint-format-in-nlopt/24491 "2019-05-22T19:22:47Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [May 22, 2019, 8:13pm UTC](https://discourse.julialang.org/t/equality-constraint-format-in-nlopt/24491/2 "2019-05-22T20:13:46Z")

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Please read [Please read: make it easier to help you](https://discourse.julialang.org/t/psa-make-it-easier-to-help-you/14757), and remember to include a minimal working example.

It’s likely because your function `a` takes arguments `x` and `grad`, but doesn’t use them. Instead, it uses `A` which isn’t defined.

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_[View the full topic](https://discourse.julialang.org/t/equality-constraint-format-in-nlopt/24491)._