matrix

[David Berry]

Is there such a thing as a 3D matrix? I thought they were by
definition 2D? For instance, how would you multiply a pair of 3D
matrices together?

David

On Fri, 3 Apr 2020 at 16:12, Laurent MICHEL
<laurent.michel at astro.unistra.fr> wrote:
>
>
>
> Le 03/04/2020 à 16:58, CresitelloDittmar, Mark a écrit :
> > Ah, I see..
> >    You're suggesting we need to support MxNxP matrices (or more).
> No, this was just an example to illustrate what I was saying.
> >    I think an earlier version of the model had an abstract Matrix, with
> > Matrix2D.. we could go back to that, allowing for Matrix3D, etc extensions.
> >    Or forgo the abstract head and just rename it.
> In the model, Matrix clearly refers to a 2D matrix.
> Regarding the model scope, there is no need for matrices of whatever
> dimension, therefore there is non need for any high level of abstraction.
> I suggest Matrix2D(nb_cols, nb_rows)
>
> Laurent
> >
> >
> >
> > On Fri, Apr 3, 2020 at 9:20 AM Laurent MICHEL
> > <laurent.michel at astro.unistra.fr
> > <mailto:laurent.michel at astro.unistra.fr>> wrote:
> >
> >     Mark,
> >
> >     To me, a (N,M) matrix is a 2D matrix with N rows and M columns (e.g. a
> >     pixel array).
> >     You want to model a ND matrix, you have to set N (matrix dimension) as
> >     an attribute plus an array of N values giving the size along of each
> >     individual axis.
> >     If you want to specifically model a 2D matrix, it would be better
> >     have 2
> >     attributes with a non confusing names (e.g. columns, rows)
> >
> >     Laurent
> >
> >     Le 02/04/2020 à 16:47, CresitelloDittmar, Mark a écrit :
> >      > Not sure I follow.  Wouldn't a Matrix2D be a Matrix with M=2, N=2?
> >      > We could discuss the names, but these seemed pretty standard and are
> >      > described as M rows, N columns.  I know I always have to go back and
> >      > review which way is rows and which is columns, but I don't deal with
> >      > matrices very often.
> >      >
> >      >
> >      >
> >      > On Thu, Apr 2, 2020 at 8:50 AM Laurent MICHEL
> >      > <laurent.michel at astro.unistra.fr
> >     <mailto:laurent.michel at astro.unistra.fr>
> >      > <mailto:laurent.michel at astro.unistra.fr
> >     <mailto:laurent.michel at astro.unistra.fr>>> wrote:
> >      >
> >      >     Dear,
> >      >
> >      >     Comment #3:
> >      >
> >      >     - The matrix operation class (Matrix) seems to refer to a 2D
> >     matrix.
> >      >     The
> >      >     class could be renamed Matrix2D to keep room for future high
> >      >     dimensionality classes
> >      >
> >      >     - The matrix dimensions are named N and M. Personally, I'm
> >     pretty sure
> >      >     to always confuse N.M and M.N. It could be safer to renamed these
> >      >     attributes with something more expressive like (row, columns)
> >      >
> >      >     LM
> >      >     --
> >      >     --
> >      >     ---- Laurent MICHEL              Tel  (33 0) 3 68 85 24 37
> >      >            Observatoire de Strasbourg  Fax  (33 0) 3 68 85 24 32
> >      >            11 Rue de l'Universite      Mail
> >      > laurent.michel at astro.unistra.fr
> >     <mailto:laurent.michel at astro.unistra.fr>
> >     <mailto:laurent.michel at astro.unistra.fr
> >     <mailto:laurent.michel at astro.unistra.fr>>
> >      >            67000 Strasbourg (France)   Web
> >     http://astro.u-strasbg.fr/~michel
> >      >     ---
> >      >
> >
> >     --
> >     ---- Laurent MICHEL              Tel  (33 0) 3 68 85 24 37
> >            Observatoire de Strasbourg  Fax  (33 0) 3 68 85 24 32
> >            11 Rue de l'Universite      Mail
> >     laurent.michel at astro.unistra.fr <mailto:laurent.michel at astro.unistra.fr>
> >            67000 Strasbourg (France)   Web http://astro.u-strasbg.fr/~michel
> >     ---
> >
>
> --
> ---- Laurent MICHEL              Tel  (33 0) 3 68 85 24 37
>       Observatoire de Strasbourg  Fax  (33 0) 3 68 85 24 32
>       11 Rue de l'Universite      Mail laurent.michel at astro.unistra.fr
>       67000 Strasbourg (France)   Web  http://astro.u-strasbg.fr/~michel
> ---