Hi folks,
I have a little mess with the way arrays are being handled in Julia. I come
from C and fortran95 and I know I can do the following things there using
pointers: imagine I have a big array A. Then I can use pointers to define W
a subsection of A, such that if I modify W then A is modified, and if I
modify A then W is modified. In this way I have one and the same data,
which I can manipulate by acting on A or on W.
I'd like to do the same thing in Julia, but don't know how. Somehow it
works if I use the whole array. For instance in this exemple:
Wall = ones(2,2)
1.0 1.0
1.0 1.0
W = Wall
1.0 1.0
1.0 1.0
W[1,1] = 0.
0.0
Wall
2x2 Array{Float64,2}:
0.0 1.0
1.0 1.0
Wall[1,2] = 2.
0.0 2.0
1.0 1.0
W
2x2 Array{Float64,2}:
0.0 2.0
1.0 1.0
...so it works both ways. That's exactly what I want, but now not just with
W and Wall being the same, but with W being a part of Wall.
I could try something like
Wall = ones(3,3)
3x3 Array{Float64,2}:
1.0 1.0 1.0
1.0 1.0 1.0
1.0 1.0 1.0
W = Wall[2:end,2:end]
1.0 1.0
1.0 1.0
W[1,1] = 3.
3.0
W
2x2 Array{Float64,2}:
3.0 1.0
1.0 1.0
Wall
3x3 Array{Float64,2}:
1.0 1.0 1.0
1.0 1.0 1.0
1.0 1.0 1.0
...so W has been updated but not Wall. If I update W itdoesn't get copied
to Wall either.
So I know how to do automatic updating when the two arrays are of the same
size, but can it be done with subsections of arrays as (I want it to be) in
the example above?
Thanks for your help and patience,
Ferran.
