Actually, you can easily get all the information at least in degenerate
form.
The two cases are:
- getPivot() ... the identity permutation can be returned
- getRank() ... it is reasonable to throw an exception stating that rank
is not available (UnsupportedOperationException, in particular). This is
*exactly* analogous to the way that many iterators do not allow remove() to
be called.
On Thu, Oct 6, 2011 at 3:21 AM, Gilles Sadowski <
gil...@harfang.homelinux.org> wrote:
> IIUC, there are things you can query from a "PivotingQRDecomposition" that
> you cannot from the "FastQRDecomposition", then when you get the interface
> "QRDecomposition", you've lost these additional features. And if you impose
> that the interface contains them, then if you request the "fast"
> implementation, and then query the "pivoting" features, what happens?
>
