Subject: Please help me come up with some good examples
From: James Amundson
Date: Sat, 28 Jun 2003 15:25:28 -0500
On Fri, 2003-06-27 at 10:29, Barton Willis wrote:
>
>
> A user can change the functions that add and multiply matrix elements.
> I once tried unsuccessfully to figure out how to do this with one of
> the other CAS. At first thought, re-defining these functions might
> not seem useful, but it is. Here is one application.
>
> Let m be the matrix of a weighted graph. Think of m as giving the
> hiway distances between cities. If no road directly connects two
> cities, let the matrix element be infinity. The diagonal elements of
> m all vanish. We can compute the shortest paths between cities by
> re-defining the functions that add and multiply matrix elements.
Thanks. I like this example -- it illustrates more than one point I
would like to make.
--Jim