The optimization problem is：

minimize log detP^−1

subject to ||Pu+ buro||\2≤ 1,

where P is a semidefinite matrix, buro is Variable, u is known.

The code is:

```
using Convex, SCS, LinearAlgebra
if VERSION < v"1.2.0-DEV.0"
LinearAlgebra.diagm(v::AbstractVector) = diagm(0 => v)
end
u=rand(3,1)
buro=Variable(3,1)
P = Semidefinite(3)#定义一个半正定矩阵
objective = logdet(inv(P))
problem = minimize(objective,norm(P*u+buro)<=1)
solve!(problem, () -> SCS.Optimizer())
computed_fidelity = evaluate(objective)
value_P = evaluate(P)
```

But error happen in `objective = logdet(inv(P))`

:

ERROR: LoadError: MethodError: no method matching inv(::Variable)

Closest candidates are:

inv(::Missing) at missing.jl:100

inv(::Complex{Float64}) at complex.jl:439

inv(::BigFloat) at mpfr.jl:464

…

Stacktrace:

[1] top-level scope at untitled-36f70f3d81c9a751a6967ac32d0812fd:9

[2] include_string(::Function, ::Module, ::String, ::String) at .\loading.jl:1088

in expression starting at untitled-36f70f3d81c9a751a6967ac32d0812fd:9

How could I modify it?

Thank you very much in advance!