This code:

```
function objective(xy)
x, y = xy
return (3y^2*x + x^3-m3)*W*(3y^2*x + x^3-m3)
end
xy0 = [x, y]
result = optimize(objective, xy0, NelderMead())
println(result)
minimizer = result.minimizer
x, y = minimizer
println("x = ", x)
println("y = ", y)
```

where W=:

```
2×2 Matrix{Float64}:
2.87989e-6 9.85217e-7
9.85217e-7 4.4135e-7
```

Returns the error:

```
MethodError: Cannot `convert` an object of type Matrix{Float64} to an object of type Float64
Closest candidates are:
convert(::Type{T}, !Matched::Base.TwicePrecision) where T<:Number at twiceprecision.jl:273
convert(::Type{T}, !Matched::AbstractChar) where T<:Number at char.jl:185
convert(::Type{T}, !Matched::CartesianIndex{1}) where T<:Number at multidimensional.jl:130
...
```

I seem to be able to multiply a scalar by a matrix by a scalar normally:

```
5*W*5
```

returns:

```
2×2 Matrix{Float64}:
7.19973e-5 2.46304e-5
2.46304e-5 1.10338e-5
```

Does anyone know why it does not work within the Optim environment, and how to fix it? Thank you!