diagonal matrices specializations

[Søren Hauberg]

ons, 03 12 2008 kl. 14:31 +0100, skrev Jaroslav Hajek:
> >> ans =
> >> diagonal matrix (5x5)
> >>    1       ..      0
> >>        2
> >>    :       3       :
> >>                4
> >>    0       ..      5
> >>
> >> the last form seems attractive, but maybe requires a bit more thinking
> >> about how to place the dots etc.
> >
> > This I don't think will work. It would be very hard to read a 20x20
> > matrix in a terminal with a width of 80 chars. But I agree, that it
> > looks nice for small matrices.
> >
> 
> But anyone trying to work visually with 20x20 matrices on a 80-column
> terminal is bound to have problems.

Not if you print it like a vector, which I think we should just always
do.

> The problem with displaying a permutation is that there are two ways
> to view a permutation matrix:
> a column permutation matrix (multiplication from the right) and row
> permutation (multiplication from the left).
> Of course, any permutation matrix can act in both ways, with inverse
> permutations.

Good point, I thought of it like that.

Søren