Totally different error (it's a missing size method). You also need to read
this:
http://docs.julialang.org/en/stable/manual/interfaces/#abstract-arrays
--Tim
On Monday, November 16, 2015 06:08:15 AM Evan wrote:
> Thank you, Tim, I understand the motivation for the approach in the link
> you sent.
>
> I'm still unable to create the type that I want. I actually want two arrays
> in my type, one 2d and the other 3d.
>
> First though, I'm still stuck on just the 2d when I try to implement your
> suggestion:
> julia> type MyType{T,N,A<:AbstractArray} <: AbstractArray{T,N}
> var::A
> end
>
> julia> MyType{T,N}(var::AbstractArray{T,N}) = MyType{T,N,typeof(var)}(var)
> MyType{T,N,A<:AbstractArray{T,N}}
>
> julia> aa = MyType(zeros(2,3))
> Error showing value of type MyType{Float64,2,Array{Float64,2}}:
> ERROR: MethodError: `size` has no method matching size(::MyType{Float64,2,
> Array{Float64,2}})
> Closest candidates are:
> size{T,n}(::AbstractArray{T,n}, ::Any)
> size(::Any, ::Integer, ::Integer, ::Integer...)
> in showarray at show.jl:1231
> in anonymous at replutil.jl:29
> in with_output_limit at ./show.jl:1271
> in writemime at replutil.jl:28
> in display at REPL.jl:114
> in display at REPL.jl:117
> [inlined code] from multimedia.jl:151
> in display at multimedia.jl:162
> in print_response at REPL.jl:134
> in print_response at REPL.jl:121
> in anonymous at REPL.jl:624
> in run_interface at ./LineEdit.jl:1610
> in run_frontend at ./REPL.jl:863
> in run_repl at ./REPL.jl:167
> in _start at ./client.jl:420
>
> julia>
>
> Performance is important, but it's not clear what I should use in place of
> abstract types; I've tried replacing AbstractArray with just Array but that
> does not appear to work.
>
> On Monday, November 16, 2015 at 1:03:05 PM UTC+1, Tim Holy wrote:
> > This fixes two problems:
> >
> > type MyType{T,N,A<:AbstractArray} <: AbstractArray{T,N}
> >
> > var::A
> >
> > end
> >
> > MyType{T,N}(var::AbstractArray{T,N}) = MyType{T,N,typeof(var)}(var)
> >
> >
> >
> > If performance matters, you should not use abstract types for fields. See
> >
> > http://docs.julialang.org/en/stable/manual/faq/#how-do-abstract-or-ambiguo
> > us-fields-in-types-interact-with-the-compiler and the section after that.
> >
> > --Tim
> >
> > On Monday, November 16, 2015 03:54:15 AM Evan wrote:
> > > For a 2d array the following works:
> > >
> > > type mytype{T}
> > >
> > > var :: AbstractMatrix{T}
> > >
> > > end
> > >
> > > julia> t = mytype(zeros(4, 3))
> > >
> > > mytype{Float64}(4x3 Array{Float64,2}:
> > > 0.0 0.0 0.0
> > > 0.0 0.0 0.0
> > > 0.0 0.0 0.0
> > > 0.0 0.0 0.0)
> > >
> > > But how do I extend this to a 3d array?
> > >
> > > julia> t = mytype(zeros(2, 4, 3))
> > > ERROR: MethodError: `convert` has no method matching
> >
> > convert(::Type{mytype{T
> >
> > > }}, ::Array{Float64,3})
> > > This may have arisen from a call to the constructor mytype{T}(...),
> > > since type constructors fall back to convert methods.
> > >
> > > Closest candidates are:
> > > call{T}(::Type{T}, ::Any)
> > > convert{T}(::Type{T}, ::T)
> > > mytype{T}(::AbstractArray{T,2})
> > >
> > > in call at essentials.jl:56
