Re: 0-1 sparse representations?

[E R]

2011/11/19 Jordi Gutiérrez Hermoso <address@hidden>:
> On 19 November 2011 15:49, E R <address@hidden> wrote:
>> I'm interested if Octave has the ability to represent a 0-1 sparse
>> matrix where there is only one 1 per row.
>
> No. Sparse matrices must be of float types.

But it is clear that octave represents permutation matrices by just
the permutation (an array of 4-byte integers).

> But why not just represent
> it as a vector of indices?

I could, but then I'd have to write my own matrix multiplication
routine. And I wouldn't be able to use it in other octave routines
which expect a matrix.

Since octave has a compact representation for permutation matrices,
perhaps it also has a special internal representation for the slightly
more general class of 0-1 matrices with only one 1 per row.