On Apr 28, 2004, at 10:14 AM, skaller wrote:

> Just try to do that in C or Fortran or Ocaml.
> You can't. In C for example, a typical operation
> on a 2D object is a double loop:
>
> 	for(i=
> 	for(j=
>
> but for 3D you need:
>
> 	for(i=
> 	for(j=
> 	for(k=
>
> that is, you have no choice implementing generalised
> tensor mathematics than to rewrite the program
> for every value of n, the rank.
>
> Yet the (tensor) maths is identical and independent
> of the rank. I guess there are numerous other
> science problems where you do a calc for a certain
> set of generalised coordinates .. and then need
> to add more coordinates and recalculate ..
> only you have to rewrite the program every time.

Not sure exactly where this is going, but I do have ocaml code where n 
is  just a parameter, and the code works across n-dimensional arrays. 
Maybe you have something more general in mind since I am not familiar 
with FISh1.


>
> For more general data stuctures of the form
>
> type 'a x = X of int * 'a | Y of 'a * 'a | Empty
>
> etc, it is clear how to write a map function.
> But each such data structure has a distinct map
> function with a distinct type.

Clean 2.0 can automatically handle your case (I believe). It can 
produce the different map's, each with a different type, automatically 
from one generic definition. Check it out!

--shiv--

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