JuliaMath
A bug?
I started some cleaning of my tests for rational transfer functions. The following fails and was commented out for RationalTransferFunctions. It seems however, it doesn't work for RationalFunctions too.
julia> using LinearAlgebra
julia> using Polynomials
julia> s = RationalFunction(Polynomial([0,1],:s))
(s) // (1)
julia> [s^2 s/(s+1); I]
ERROR: ArgumentError: number of columns of each array must match (got (2, 1))
Stacktrace:
[1] _typed_vcat(#unused#::Type{Any}, A::Tuple{Matrix{Any}, Matrix{Any}})
@ Base .\abstractarray.jl:1553
[2] typed_vcat(::Type{Any}, ::Matrix{Any}, ::Matrix{Any})
@ Base .\abstractarray.jl:1567
[3] typed_hvcat(::Type{Any}, ::Tuple{Int64, Int64}, ::RationalFunction{Int64, :s, Polynomial{Int64, :s}}, ::Vararg{Any, N} where N)
@ Base .\abstractarray.jl:1957
[4] hvcat(::Tuple{Int64, Int64}, ::RationalFunction{Int64, :s, Polynomial{Int64, :s}}, ::Vararg{Any, N} where N)
@ Base .\abstractarray.jl:1932
[5] top-level scope
@ REPL[4]:1
I'm thinking I really wants to be a square matrix:
julia> using LinearAlgebra
julia> [1 2; I]
ERROR: ArgumentError: number of columns of each array must match (got (2, 1))
This works, but ends up with an odd type:
julia> [s^2 s/(s+1); 0 I]
2×2 Matrix{Any}:
(s^2) // (1) (s) // (1 + s)
0 UniformScaling{Bool}(true)
but the same is true if s is just a number.
Interesting. Thus, this is an error in LinearAlgebra. Should I make an issue for this?
Recently I fighted with type piracy in DescriptorSystems. I was not able to get rid of it, but enhanced my handling of such cases (e.g., by internally converting the above to [[1] [2]; I], which works). Now I realize, this was not entirely my fault!
I'd say it is a design choice, where I is always square. What are you expecting the output to be?
On Sun, Nov 7, 2021 at 8:02 AM Andreas Varga @.***> wrote:
Interesting. Thus, this is an error in LinearAlgebra. Should I make an issue for this?
Recently I fighted with type piracy in DescriptorSystems. I was not able to get rid of it, but enhanced my handling of such cases (e.g., by internally converting the above to [[1] [2]; I], which works). Now I realize, this was not entirely my fault!
— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/JuliaMath/Polynomials.jl/issues/365#issuecomment-962606854, or unsubscribe https://github.com/notifications/unsubscribe-auth/AADG6TD6GBZA4LERGDYB7CLUKZ2F5ANCNFSM5HQWLEWQ . Triage notifications on the go with GitHub Mobile for iOS https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675 or Android https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub.
-- John Verzani Department of Mathematics College of Staten Island, CUNY
Only the square case is implemented in LinearAlgebra.UniformScaling at line #394:
promote_to_arrays_(n::Int, ::Type{Matrix}, J::UniformScaling{T}) where {T} = copyto!(Matrix{T}(undef, n,n), J)
With my handling of type piracy I get:
julia> using DescriptorSystems
[ Info: Precompiling DescriptorSystems [a81e2ce2-54d1-11eb-2c75-db236b00f339]
julia> [1 2; I]
3×2 Matrix{Int64}:
1 2
1 0
0 1
I would be happy to get the same with LinearAlgebra too.
I see. That makes some sense at first glance.
On Sun, Nov 7, 2021 at 8:35 AM Andreas Varga @.***> wrote:
Only the square case is implemented in LinearAlgebra.UniformScaling at line #394: promote_to_arrays_(n::Int, ::Type{Matrix}, J::UniformScaling{T}) where {T} = copyto!(Matrix{T}(undef, n,n), J)
With my handling of type piracy I get:
julia> using DescriptorSystems
[ Info: Precompiling DescriptorSystems [a81e2ce2-54d1-11eb-2c75-db236b00f339]
julia> [1 2; I]
3×2 Matrix{Int64}:
1 2
1 0
0 1
I would be happy to get the same with LinearAlgebra too.
— You are receiving this because you commented.
Reply to this email directly, view it on GitHub https://github.com/JuliaMath/Polynomials.jl/issues/365#issuecomment-962611779, or unsubscribe https://github.com/notifications/unsubscribe-auth/AADG6TDIFFKF6ZCSSDMLSRTUKZ6DHANCNFSM5HQWLEWQ . Triage notifications on the go with GitHub Mobile for iOS https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675 or Android https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub.
-- John Verzani Department of Mathematics College of Staten Island, CUNY
Apparently we have to wait for Julia 1.8 to be fixed in LinearAlgebra. Should we close this issue?