[Gretl-devel] Re: surprising type change
On Mon, Nov 4, 2024 at 6:39 PM Sven Schreiber
<sven.schreiber(a)fu-berlin.de> wrote:
I have been struggling with this unexpected behavior:
<hansl>
matrix m = {0.5}
eval typename(m) # matrix
b = _(hu=m)
eval typename(b.hu) # scalar
</hansl>
So the mere copy of the object changes its type here. (Also happens
outside of a bundle, but there you can force the type more easily.) I
don't think that should happen.
What exactly caused you to struggle? It's expected behavior in gretl
that a 1 x 1 matrix "decays" to a scalar outside of "genr" unless you
prevent that, but the idea is that a scalar ought to be usable as a 1
x 1 matrix if required. If you wanted to do something with b.hu that
was not allowed on account of it not being a matrix I think that would
be a bug. (Hmm, maybe trying for m[1,1]?)
However, you can ensure that m (1 x 1) maintains its matrix type
inside a bundle:
matrix m = {0.5}
bundle b = _()
matrix b.hu = m
eval typename(b.hu) # matrix
Allin