[Gretl-devel] Re: eval and matrix right division (/)
On Sat, Jan 14, 2023 at 5:59 AM Sven Schreiber
<sven.schreiber(a)fu-berlin.de> wrote:
Hi, there is a disconnect here somehow:
<console>
? m = ones(4,3)
? div = {1, 0.2, 5}
? X = m / div
Ungültiges Argument # = invalid arg
What version of gretl is giving you that error? I'm not seeing any error there.
? eval m/ div
0,23810
0,23810
0,23810
0,23810
</console>
But obviously the result is wrong and it's clear that in linear algebra terms there
is no solution. So what is eval doing there?
It's doing just what Matlab's mrdivide() does, namely, computing a
least squares solution in the non-square case. This point is not
documented in the matrix chapter of the Gretl User's Guide, something
that should be fixed.
Allin