ctrb not working passing A and B matrices as parameters

[martinamaggio]

Reporting a problem with the function ctrb (running version 0.9.0 of the ControlSystems package, julia version 1.5.3, on Mac OS Catalina 10.15.7).

When I pass the system as parameter, there is no problem executing the function. When I pass the matrices A and B as parameters I get the following error message

julia> ctrb(A,B)
ERROR: MethodError: no method matching ctrb(::Array{Float64,2}, ::Array{Float64,1})
Closest candidates are:
  ctrb(::AbstractArray{T,2} where T, ::AbstractArray{T,2} where T) at
  ~/.julia/packages/ControlSystems/lhpZ5/src/matrix_comps.jl:132

Simple code example to reproduce the error:

using ControlSystems

A = [0.3 0; 0.1 -5]
B = [0; 1]
C = [1 1]
D = 0

sys_ss = ss(A, B, C, D)
ctrb(sys_ss)
ctrb(A, B)

[mfalt]

The function requires two matrices (Array{Float64,2}):

Closest candidates are:
  ctrb(::AbstractArray{T,2} where T, ::AbstractArray{T,2} where T)

but you have supplied B as a vector (Array{Float64,1}).

no method matching ctrb(::Array{Float64,2}, ::Array{Float64,1})

The ss constructor is nice to automatically handle that and reshape to a matrix, but apparently not ctrb. We should maybe add that.

[martinamaggio]

Aha, I confirm it works with reshape. I think it would definitively be more user-friendly to integrate reshaping (especially because one doesn't need to reshape with obsv).

[mfalt]

Aha, I confirm it works with reshape. I think it would definitively be more user-friendly to integrate reshaping (especially because one doesn't need to reshape with obsv).

I don't think we have anything like that implemented for obsv, but the difference is that, for example, C = [1 0] already is a 1x2 matrix. But, it seems that everything should already work if we allow B (or C in obsv) to be vectors.

However, we should probably not allow C to be a vector since they are interpreted as column vectors.