getindex of range in IdentityMultiple

[Christian Schilling]

The type of ind has to be restricted to Integer and another method for StepRange (or the supertype OrdinalRange or even that one's supertype AbstractRange) needs to be added.

MathematicalSystems.jl/src/identity.jl

Lines 87 to 98 in a456045

 function Base.getindex(𝐼::IdentityMultiple, inds...) 
     any(idx -> idx > 𝐼.n, inds) && throw(BoundsError(𝐼, inds)) 
     getindex(𝐼.M, inds...) 
 end 
  
 function Base.getindex(𝐼::IdentityMultiple{T}, ind) where {T} 
     if 1 ≤ ind ≤ 𝐼.n^2 
         return rem(ind-1, 𝐼.n+1) == 0 ? 𝐼.M.λ : zero(T) 
     else 
         throw(BoundsError(𝐼, ind)) 
     end 
 end 

julia> I = IdentityMultiple(1.0, 2)
IdentityMultiple{Float64} of value 1.0 and order 2

julia> Diagonal(I)
ERROR: MethodError: no method matching isless(::Int64, ::StepRange{Int64,Int64})
Closest candidates are:
  isless(::Missing, ::Any) at missing.jl:66
  isless(::Real, ::AbstractFloat) at operators.jl:157
  isless(::Real, ::Real) at operators.jl:346
  ...
Stacktrace:
 [1] <(::Int64, ::StepRange{Int64,Int64}) at ./operators.jl:268
 [2] <=(::Int64, ::StepRange{Int64,Int64}) at ./operators.jl:317
 [3] getindex(::IdentityMultiple{Float64}, ::StepRange{Int64,Int64}) at .julia/dev/MathematicalSystems/src/identity.jl:93