[GAP Forum] [ gauss ] Displaying a sparse matrix

[Sebastian Gutsche]

Dear Anvita,

thank you for the bug reports and comments for the Gauss package.

I will look at them shortly, try to fix as much as possible (or
introduce standards in the manual)
and will then write a longer reply, adressing all of your comments.

Best,
Sebastian


> Date: Sun, 18 Mar 2018 10:58:46 -0300
> From: Anvita <anvita21 at gmail.com>
> To: GAP forum <forum at gap-system.org>
> Subject: [GAP Forum] [ gauss ] Displaying a sparse matrix
> Message-ID:
> 	<CAAwatYUXiNB9NfDnPxbC2H0jACM+yT--j2cXWYKKzDSTUh=_Jw at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Dear Forum,
>
> With the "gauss" package loaded, I noticed that "Display" behaves strangely
> when the indices in a sparse matrix are not strictly increasing. I am
> assuming it is allowed to have non-increasing indices because the manual
> does not require otherwise and also because the conversion to an ordinary
> matrix works as expected. The whole concept of a sparse matrix suggests, in
> my opinion, that we should not worry about the linear ordering of matrix
> entries any more.
>
> Anvita
>
> gap> LoadPackage("gauss");
> ???????????????????????????????????????????????????????????????
> Loading  Gauss 2017.06.14 (Extended Gauss functionality for GAP)
> by Simon Goertzen (http://wwwb.math.rwth-aachen.de/goertzen).
> Homepage: http://homalg-project.github.io/homalg_project/Gauss/
> ???????????????????????????????????????????????????????????????
> true
>
> gap> SN := SparseMatrix( 2, 3,
>>                   [ [ 2 ], [ 3, 1 ] ],
>>                   [ [ 1 ], [ 3, 2 ] ] * One( GF(5) ) );
> <a 2 x 3 sparse matrix over GF(5)>
>
> gap> Display( ConvertSparseMatrixToMatrix ( SN ) );  # expected output
>  . 1 .
>  2 . 3
>
> gap> Display(SN);   # corrupted output
>  . 1 .
>  . . 3 2 . .