# Gurobi for quadratic constraint problems

**URL:** <https://discourse.julialang.org/t/gurobi-for-quadratic-constraint-problems/28956>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [September 19, 2019, 5:10pm UTC](https://discourse.julialang.org/t/gurobi-for-quadratic-constraint-problems/28956 "2019-09-19T17:10:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Ariel\_Cruz\_Cruz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ariel_cruz_cruz/32/10377_2.png) [@Ariel\_Cruz\_Cruz](https://discourse.julialang.org/u/Ariel_Cruz_Cruz)\
**Post date:** [September 19, 2019, 5:10pm UTC](https://discourse.julialang.org/t/gurobi-for-quadratic-constraint-problems/28956/1 "2019-09-19T17:10:58Z")

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Hi, I want to know if I can use the Gurobi solver to solve the next problem:

```julia
min: ( (x1-1)^2 + (x2-2)^2 + (x3-1)^2 ) / 2
 
s.t.:
x1, x2, x3 >= 0
x1 * x3 <= 2
x2 * x3 <= 2

```

Because when I try to do that I get this error:  
`Gurobi.GurobiError(10020, "Q matrix is not positive semi-definite (PSD)")`

So, I want to know exactly what kind of quadratic constraint problems I can solve using Gurobi

Thanks

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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:** [September 19, 2019, 5:12pm UTC](https://discourse.julialang.org/t/gurobi-for-quadratic-constraint-problems/28956/2 "2019-09-19T17:12:33Z")

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Please provide a link if you post in multiple places: [https://github.com/JuliaOpt/Gurobi.jl/issues/255](https://github.com/JuliaOpt/Gurobi.jl/issues/255)

I’ve answered in the Github issue 🙂

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<div class="post-metadata">

**Author:** ![Ariel\_Cruz\_Cruz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ariel_cruz_cruz/32/10377_2.png) [@Ariel\_Cruz\_Cruz](https://discourse.julialang.org/u/Ariel_Cruz_Cruz)\
**Post date:** [September 19, 2019, 5:14pm UTC](https://discourse.julialang.org/t/gurobi-for-quadratic-constraint-problems/28956/3 "2019-09-19T17:14:48Z")

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ohh, sorry, I hasn’t notice that. thanks… I will answer you there 😉