# MethodError: no method matching ^(::QuadExpr, ::Float64)

**URL:** <https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247>\
**Category:** Optimization (Mathematical)\
**Created:** [March 21, 2022, 11:27pm UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247 "2022-03-21T23:27:19Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Eric.O](https://avatars.discourse-cdn.com/v4/letter/e/9dc877/32.png) [@Eric.O](https://discourse.julialang.org/u/Eric.O)\
**Post date:** [March 21, 2022, 11:27pm UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247/1 "2022-03-21T23:27:19Z")

</div>

I am trying to run this code in Julia but I keep getting this error  
MethodError: no method matching ^(::QuadExpr, ::Float64)

below is my code: I will be grateful if someone can help me correct this error. Thanks in advance

using JuMP  
using Mosek  
using MosekTools  
model= Model(Mosek.Optimizer)

NumVar=5

#create your variables  
@variable(model, x[i=1:NumVar], Bin)  
@variable(model, y[i=1:NumVar], Bin)  
@variable(model, z[i=1:NumVar], Bin)  
@variable(model, r[i=1:NumVar], Bin)  
@variable(model, a[i=1:NumVar], Bin)  
@variable(model, b[i=1:NumVar], Bin)  
@variable(model, X\>=0)  
@variable(model, Y\>=0)  
@variable(model, R\>=0)

#Define your constraints  
for i in 1:NumVar

```
@constraint(model, x[i] + X == a[i])
@constraint(model, y[i] + Y == b[i])
@constraint(model, z[i] + r[i] == R)
@constraint(model, z[i] >= (x[i]^2 + y[i]^2)^0.5)

```

end

#Specify Objective function  
@objective(model, Min,R)

#Summary

@show model  
print(model)  
optimize!(model)  
@show termination\_status(model)  
@show primal\_status(model)  
@show dual\_status(model)  
@show objective\_value(model)  
for i in 1:NumVar  
println("x[$i] = ", value(x[i]))  
println("y[$i] = ", value(y[i]))  
println("z[$i] = ", value(z[i]))  
end  
@show value(X)  
@show value(Y)

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<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:** [March 21, 2022, 11:48pm UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247/2 "2022-03-21T23:48:30Z")

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> [@Eric.O](#):
>
> `@constraint(model, z[i] >= (x[i]^2 + y[i]^2)^0.5)`

You need to write this as a conic constraint:

```julia
@constraint(model, [z[i], x[i], y[i]] in SecondOrderCone())

```

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<div class="post-metadata">

**Author:** ![Eric.O](https://avatars.discourse-cdn.com/v4/letter/e/9dc877/32.png) [@Eric.O](https://discourse.julialang.org/u/Eric.O)\
**Post date:** [March 22, 2022, 12:08am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247/3 "2022-03-22T00:08:03Z")

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Thank you for the response.  
I did that but this is the output I had

[𝑧1,𝑥1,𝑦1]∈MathOptInterface.SecondOrderCone(3)[𝑧2,𝑥2,𝑦2]∈MathOptInterface.SecondOrderCone(3)[𝑧3,𝑥3,𝑦3]∈MathOptInterface.SecondOrderCone(3)[𝑧4,𝑥4,𝑦4]∈MathOptInterface.SecondOrderCone(3)[𝑧5,𝑥5,𝑦5]∈MathOptInterface.SecondOrderCone(3)

Is this the same as z[i] \>= sqrt(x[i]^2 + y[i]^2) where i starts from 1 to 5?

Thus I was expecting an output like

z1\>= (x1^2 + y1^2)^0.5  
z2\>= (x2^2 + y2^2)^0.5  
z3\>= (x3^2 + y3^2)^0.5  
z4\>= (x4^2 + y4^2)^0.5  
z5\>= (x5^2 + y5^2)^0.5

Is the output I had and what I was expecting the same?

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<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:** [March 22, 2022, 12:22am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247/4 "2022-03-22T00:22:41Z")

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It’s the same. See [Constraints · JuMP](https://jump.dev/JuMP.jl/stable/manual/constraints/#Second-order-cone-constraints)

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<div class="post-metadata">

**Author:** ![Eric.O](https://avatars.discourse-cdn.com/v4/letter/e/9dc877/32.png) [@Eric.O](https://discourse.julialang.org/u/Eric.O)\
**Post date:** [March 22, 2022, 3:37am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-quadexpr-float64/78247/5 "2022-03-22T03:37:42Z")

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Thank you very much for the support