[julia-users] help with slowness in array wrapper

[Sheehan Olver]

Hi,

I have the code below that wraps an array to allow non-standard index 
ranges, as part of an implementation of a linear algebra algorithm (Givens 
rotations).  Surprisingly the setindex! routine is taking a significant 
portion of the computational cost, 30%, so I think I must not be getting 
the command to compile properly.  Any hints?


Cheers,

Sheehan






type ShiftArray{T<:Number}
  data::Array{T,2}
  colindex::Integer
  rowindex::Integer
end

Base.setindex!{T<:Number}(S::ShiftArray{T},x::T,k::Integer,j::Integer)=(S.data[k
 
+ S.rowindex, j + S.colindex] = x)