[Gretl-devel] Re: qrdecomp with column pivoting?
On Tue, 7 Jun 2022, Sven Schreiber wrote:
Am 06.06.2022 um 18:55 schrieb Cottrell, Allin:
>
> Meanwhile (in git), you can now call QR with pivoting, the trigger
> being a non-null third (matrix-pointer) argument.
For m < n (more rows) this seems to crash gretl. (I don't need it, but I
kind of thought it might cause trouble.)
There was a guard against that in place, but maybe it didn't come
soon enough. Now fixed in git and snapshots.
BTW, the qrdecomp() doc is now more explicit, and includes the
requirement that m >= n. (I gather that for short-and-fat input you
really want the LQ decomposition rather than QR, but I don't see a
need to implement that yet.)
Allin