[GOODIE] Matrix-raok

Bert Freudenberg bert at isg.cs.uni-magdeburg.de
Fri Nov 22 13:40:07 UTC 2002


On Fri, 22 Nov 2002, Richard A. O'Keefe wrote:

> The numerical linear algebra package recently posted to this list has
> *far* wider coverage.  

I was talking about the Matrix class in the Croquet image. The one we
discussed recently because the plugin was missing. It would be nice if the
author (Dave?) would pipe up and post it as goodie, too.

> My little 'Matrix' class is now of interest mainly (solely?) for these
> two reasons:
> 
> (1) I deliberately decided NOT to let you specify a class by the underlying
>     array. [...]

Yep.

> (2) A very major point was my decision, influenced by APL and S-Plus,
>     that ordinary arithmetic binary selectors should *consistently* be
>     interpreted as elementwise operations.  That is,
>     / 1 2 \  * / 1 0 \  = / 
>     \ 3 4 /    \ 0 1 /

Agreed. This is exactly what the Matrix class in Croquet does (actual 
code):

| a b |
a := Matrix[2,2] fill: #(1 2 3 4).
b := Matrix[2,2] fill: #(1 0 0 1).
a * b "[1 0
      0 4]"

-- Bert




More information about the Squeak-dev mailing list