# Conditional constraint if else in JuMP

**URL:** <https://discourse.julialang.org/t/conditional-constraint-if-else-in-jump/6795>\
**Category:** Optimization (Mathematical)\
**Tags:** question\
**Created:** [October 31, 2017, 8:29am UTC](https://discourse.julialang.org/t/conditional-constraint-if-else-in-jump/6795 "2017-10-31T08:29:34Z")\
**Posts on this page:** 1\
**Showing post:** 12

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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 4, 2020, 5:59pm UTC](https://discourse.julialang.org/t/conditional-constraint-if-else-in-jump/6795/12 "2020-05-04T17:59:13Z")

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> [@jmatovu](#):
>
> @NLconstraint(model, eq[i in I], 2y[i]^3 - 1, if x0[i]\>=0

This is not a constraint. Do you mean

```Julia
@NLconstraint(model, eq[i in I; x0[i] >= 0], 2y[i]^3 - 1 == x0[i])

```

which is equivalent to

```Julia
for i in I
    if x0[i] >= 0
        @NLconstraint(model, 2y[i]^3 - 1 == x0[i])
    end
end

```

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