partial trace for non-numeric matrices

[lkapelevich]

Thanks for this package!
Would it be OK to remove the <:Number restriction in https://github.com/iitis/QuantumInformation.jl/blob/master/src/ptrace.jl#L11? My use case is to calculate ptrace with JuMP variables and things seem to work with just ρ::AbstractMatrix

[lpawela]

@lkapelevich we will try to implement this in some reasonable timeframe.

[lpawela]

@lkapelevich I removed the requirement, you can see it here a213dd3. Is this sufficient for your use case?

[lkapelevich]

Yep that's what I had in mind!