[Gretl-devel] Re: nullspace() weirdness
On Mon, May 8, 2023 at 12:24 PM Riccardo (Jack) Lucchetti
<p002264(a)staff.univpm.it> wrote:
I just realised that our implementation of nullspace() contains a mild
inconsistency, that I think we should get rid of. Consider the following
script [.which displays an apparent inconsistency]
The inconsistency lies in the fact that the result of nullspace() is
normalised by equating the largest element to 1 if has one column, and to
be orthonormal otherwise. This may be a little unfortunate if one assumes
(as I was doing) that the result is always orthonormal.
I agree, this doesn't look nice. Not sure why we thought it was a good
idea in the first place.
For now I've just defined out the offending code in gretl_matrix.c, in
case there are any second thoughts.
Allin