# Mosek does not support an objective function of type ScalarQuadraticFunction

**URL:** <https://discourse.julialang.org/t/mosek-does-not-support-an-objective-function-of-type-scalarquadraticfunction/94702>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [February 15, 2023, 9:53pm UTC](https://discourse.julialang.org/t/mosek-does-not-support-an-objective-function-of-type-scalarquadraticfunction/94702 "2023-02-15T21:53:01Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![A\_M](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/a_m/32/46038_2.png) [@A\_M](https://discourse.julialang.org/u/A_M)\
**Post date:** [February 15, 2023, 9:53pm UTC](https://discourse.julialang.org/t/mosek-does-not-support-an-objective-function-of-type-scalarquadraticfunction/94702/1 "2023-02-15T21:53:01Z")

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I am getting this error when I use a quadratic term in the objective while using Mosek.

`The solver does not support an objective function of type MathOptInterface.ScalarQuadraticFunction{Float64}.`

Is this something that can be fixed?

---

<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:** [February 16, 2023, 4:23am UTC](https://discourse.julialang.org/t/mosek-does-not-support-an-objective-function-of-type-scalarquadraticfunction/94702/2 "2023-02-16T04:23:15Z")

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Do you have a reproducible example? This should probably have been bridged.

Otherwise, instead of

```julia
model = Model()
@variable(model, x)
@objective(model, Min, x^2)

```

do

```julia
model = Model()
@variable(model, x)
@variable(model, t)
@constraint(model, t >= x^2)
@objective(model, Min, t)

```

---

<div class="post-metadata">

**Author:** ![A\_M](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/a_m/32/46038_2.png) [@A\_M](https://discourse.julialang.org/u/A_M)\
**Post date:** [February 16, 2023, 4:35am UTC](https://discourse.julialang.org/t/mosek-does-not-support-an-objective-function-of-type-scalarquadraticfunction/94702/3 "2023-02-16T04:35:42Z")

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Here you are:

```julia
model = direct_model(Mosek.Optimizer())
@expression(model, Y[s=1:n], sum(X[s,i]^2 * a[s,i] ) for i=1:m))
@objective(model, min, sum(Y[s] for s in 1:n))

```

I am using `Y` Expression somewhere else as well.

---

<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:** [February 16, 2023, 4:46am UTC](https://discourse.julialang.org/t/mosek-does-not-support-an-objective-function-of-type-scalarquadraticfunction/94702/4 "2023-02-16T04:46:58Z")

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> [@A\_M](#):
>
> `model = direct_model(Mosek.Optimizer())`

Mosek doesn’t natively support quadratic functions and constraints. They need to be reformulated into second order cones.

Use `model = Model(Mosek.Optimizer)`.

See [Models · JuMP](https://jump.dev/JuMP.jl/stable/manual/models/#Direct-mode) for more details.