Problem with Array in struct in Julia language - julia

Question

I've a problem with the following struct:
struct OdeSol{typ, rng, n}
t::rng
x::Array{typ}
v::Array{typ}
end
OdeSol(typ, rng, n) = OdeSol(rng, Array{typ}(undef, n, length(rng)), Array{typ}(undef, n, length(rng)))
where t_range=tlim[1]:Δt:tlim[2], typeof(x0[1]) is Float64 and size(x0)[1] is an integer (size(x0)[1]=2).
When I launch sol = OdeSol(typeof(x0[1]), t_range, size(x0)[1]) I got the following error:
MethodError: no method matching Array{0.0:0.01:10.0,N} where N(::UndefInitializer, ::Array{Float64,2}, ::Int64)
Closest candidates are:
Array{0.0:0.01:10.0,N} where N(::UndefInitializer, !Matched::Int64, ::Int64) where T at boot.jl:421
Array{0.0:0.01:10.0,N} where N(::UndefInitializer, !Matched::Int64, ::Int64, !Matched::Int64) where T at boot.jl:422
Array{0.0:0.01:10.0,N} where N(::UndefInitializer, !Matched::Integer, ::Integer) where T at baseext.jl:17
...
Stacktrace:
[1] OdeSol(::StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}, ::Array{Float64,2}, ::Array{Float64,2}) at ./In[10]:8 (repeats 2 times)
[2] top-level scope at In[11]:1
[3] include_string(::Function, ::Module, ::String, ::String) at ./loading.jl:1091
Anyone can help me?

Answer 1

You seem to be mixing the parametric types with the field values within the struct.
On top of that it is worth to use capital letters for type names.
Looking at the parameters it also seems that you are looking for matrices (that is 2-dimensional arrays)/
Perhaps you mean the following thing:
struct OdeSol{T, R}
t::R
x::Matrix{T}
v::Matrix{T}
end
OdeSol{T,R}(rng::R, n) where {T,R} = OdeSol{T,R}(rng, Matrix{T}(undef, n, length(rng)), Matrix{T}(undef, n, length(rng)))
And now sample usage:
julia> OdeSol{Int, Vector{Int}}([1,2,3],4)
OdeSol{Int64,Array{Int64,1}}([1, 2, 3], [0 0 0; 0 0 0; 0 0 0; 0 0 0], [0 0 0; 0 0 0; 0 0 0; 0 0 0])