RE: [Q] multidimensional array?

[Ted Harding]

On 24-Mar-99 Jae-Hoon Jeong wrote:
> Hello.
> Is it possible using mutidimensional array more than 2
> in octave?

Although it is not possible to do it directly, in the form A(i,j,k), it
can be simulated by computing an index into a linear array stored in a
structure:

octave:11> A.ndim = 3;
octave:12> A.dims = [3 2 4];
octave:13> A.elems = ...
>  [111 112 113 114 121 122 123 124 \
>   211 212 213 214 221 222 223 224 \
>   311 312 312 314 321 322 323 324 ];
octave:14> function y = elem(A,i,j,k)      
> y = A.elems(k + A.dims(3)*(j-1) + A.dims(3)*A.dims(2)*(i-1));
> endfunction
octave:15> elem(A,1,2,3)
ans = 123
octave:16> elem(A,2,2,4)
ans = 224

(where the last index varies most rapidly along the linear array and the
first least rapidly).

The function definition gets a bit more complicated if you have to allow
for arbitrary numbers of dimensions (use varargs)

Ted.

--------------------------------------------------------------------
E-Mail: (Ted Harding) <address@hidden>
Date: 24-Mar-99                                       Time: 11:58:30
------------------------------ XFMail ------------------------------