I'm puzzled that a type consisting only of 2 integers doesn't qualify as
"bitstype". Further experiment shows that the array seems to be an array of
references, I don't know how to implement zero, and generally that I'm a bit
lost :) My goal is to get a densely packed array of data. I assume that will
use less memory and generate faster code; if not, maybe I should change my goal.
BTW, my real use has a type more heterogeneous than 2 Int's, so a solution that
uses a 2D array doesn't really generalize appropriately for me.
module TT
import Base.zero
type Stuff
a::Int
b::Int
end
function zero(x::Stuff)
Stuff(0, 0)
end
end
julia> v=Array(TT.Stuff, 3) #as before
3-element Array{TT.Stuff,1}:
#undef
#undef
#undef
julia> s=TT.Stuff(3, 5)
TT.Stuff(3,5)
julia> v=fill(s, 2)
2-element Array{TT.Stuff,1}:
TT.Stuff(3,5)
TT.Stuff(3,5)
julia> s.a=900
900
julia> v ###OOPS: every array element points to the same instance
2-element Array{TT.Stuff,1}:
TT.Stuff(900,5)
TT.Stuff(900,5)
julia> zero(TT.Stuff) # This is probably what needs to work for zeros() to
work
ERROR: MethodError: `zero` has no method matching zero(::Type{TT.Stuff})
!julia> zero(TT.Stuff(1, 1)) # this at least calls the right c'tor
TT.Stuff(0,0)
Ross
________________________________________
From: [email protected] [[email protected]] on behalf of
Lutfullah Tomak [[email protected]]
Sent: Tuesday, May 10, 2016 12:04 AM
To: julia-users
Subject: [julia-users] undefined reference error
You need to initialize array entries if you don't have eltype as bitstype.
Here, undefined reference means you had not initialize the entry. And, full
type assignment works because it initializes the entry.
