serious bug in array2

[Ralf Hemmecke]

I am sure you agree that this is incorrect.
I actually used Fraction(Integer) instead of Integer where printing the
array a results in

>> System error:
The value
0
is not of type
CONS

Patch is attached.

Ralf

===========================================================

%%% (1) -> arr2 ==> array2 $ IndexedTwoDimensionalArray(Integer,0,0)
Type: Void
%%% (2) -> a := arr2([[11,12,13],[21,22,23],[31,32,33],[41,42,43]]);
Type: IndexedTwoDimensionalArray(Integer,0,0)
%%% (3) -> [minRowIndex a, maxRowIndex a, minColIndex a, maxColIndex a]

(3) [0, 2, 0, 3]
Type: List(NonNegativeInteger)
%%% (4) -> a

+11 12 13 0+
| |
(4) |21 22 23 0|
| |
+31 32 33 0+
Type: IndexedTwoDimensionalArray(Integer,0,0)

[Waldek Hebisch]

On Thu, Jan 15, 2026 at 03:19:39PM +0100, 'Ralf Hemmecke' via FriCAS - computer algebra system wrote:
> I am sure you agree that this is incorrect.
> I actually used Fraction(Integer) instead of Integer where printing the
> array a results in
>
> >> System error:
> The value
> 0
> is not of type
> CONS
>
> Patch is attached.

Thanks. However, together with the patch it would be good to
commit a test (to bugs2026.input). Say something like

a := array2([[1, 2], [3, 4], [5, 6]])
testEquals("nrows(a)", "3")
testEquals("ncols(a)", "2")

Could you commit both the patch + a test?

> Ralf
>
> ===========================================================
>
> %%% (1) -> arr2 ==> array2 $ IndexedTwoDimensionalArray(Integer,0,0)
> Type: Void
> %%% (2) -> a := arr2([[11,12,13],[21,22,23],[31,32,33],[41,42,43]]);
> Type: IndexedTwoDimensionalArray(Integer,0,0)
> %%% (3) -> [minRowIndex a, maxRowIndex a, minColIndex a, maxColIndex a]
>
> (3) [0, 2, 0, 3]
> Type: List(NonNegativeInteger)
> %%% (4) -> a
>
> +11 12 13 0+
> | |
> (4) |21 22 23 0|
> | |
> +31 32 33 0+
> Type: IndexedTwoDimensionalArray(Integer,0,0)
>

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> From 6d6515e7da8ef21502f1e85d743f2634bf407e7c Mon Sep 17 00:00:00 2001
> From: Ralf Hemmecke <ra...@hemmecke.org>
> Date: Thu, 15 Jan 2026 15:17:18 +0100
> Subject: bugfix: number of rows and columns were wrongly initialized
>
> ---
> src/algebra/array2.spad | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/algebra/array2.spad b/src/algebra/array2.spad
> index 3d7f499b..38bcb342 100644
> --- a/src/algebra/array2.spad
> +++ b/src/algebra/array2.spad
> @@ -932,7 +932,7 @@ TwoDimensionalArrayCategory(R, Row, Col) : Category == Definition where
> empty?(ll) => qnew(0, 0)
> m := #ll::NNI
> n := #first(ll)::NNI
> - a2 := qnew(n, m)
> + a2 := qnew(m, n)
> for i in minRowIndex(a2)..maxRowIndex(a2) for l in ll repeat
> if #l ~= n then
> error "array2: rows of different lengths"
> --
> 2.43.0
>


--
Waldek Hebisch