isolating a special case

[Dushan Mitrovich]

Przemek Klosowski <przemek at jazz.ncnr.nist.gov> wrote:
>       fieldmatrix = (range<0.1)*selffield + (0.1<=range)*otherfield
>
> Make selffield a sparse matrix? It's still wasteful in that it does
> uneeded sparse matrix lookups and adds the resulting zeros.

I'll take a look at this option.  Right now I'm exploring using switch/case
to see how well that might work.  Thanks for the suggestion.

- Dushan