[gambit-list] performance

Álvaro Castro-Castilla alvaro.castro.castilla at gmail.com
Tue Apr 20 05:54:22 EDT 2010


El 20 de abril de 2010 08:25, Andrew Reilly <areilly at bigpond.net.au>escribió:

> Sorry for coming in late!
>
> I don't think that your C program is doing what you thing it should be.
>  Certainly not
> what your list-based scheme program is.  Specifically, the array indexing
> in :
>
>        for (j=0; j< size_y; j++) {
>                for (i=0; i< size_x; i++) {
>                        p.x = i;
>                        p.y = j;
>                        dist = distance_point_point(&p, &refp);
>                        if ( dist > 255 ) {
>                                block[i*j] = 255;
>                        } else {
>                                block[i*j] = dist;
>                        }
>                }
>        }
>
> should probably be block[j*size_x + i].  What you have there is
> only setting a very limited subset of the elements of the array.
>
> Cheers,
>
> --
> Andrew
>


Yes you are right about that and I realized later. I wrote that stuff very
quickly just to measure times. I made the same mistake in the scheme code
also IRCC :)

Thanks for you reply!

Álvaro
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