matrix: M[range(2,-1,-1),:] returns junk

[dfdeshom]

In the following example, A should be "upside down", but it's not

sage: A = random_matrix(ZZ,3); A

[ 1  3 -1]
[ 4 -3 -1]
[-1  0 -1]

sage: A[range(2,-1,-1),:]

[ 1  3 -1]
[ 4 -3 -1]
[-1  0 -1]

The problem is with set(), which doesn't preserve order.

Component: linear algebra

Issue created by migration from https://trac.sagemath.org/ticket/2871

[sagetrac-cwitty]

comment:2

Attachment: 2871.patch.gz

The code and doctests look good, and doctests pass in sage/matrix in Sage 2.11. Unfortunately, applying the patch to Sage 3.0 alpha 2 (the latest I have at the moment) gives a rejected hunk.

[dfdeshom]

patch against alpha2

[sagetrac-cwitty]

comment:3

Attachment: 2871-alpha2.patch.gz

With the revised 2871-alpha2.patch, the patch applies and doctests pass in sage/matrix for sage 3.0 alpha2.

Didier, thanks for making the changes I requested on IRC!

Looks good, please apply.

[sagetrac-mabshoff]

comment:4

Merged 2871-alpha2.patch in Sage 3.0.alpha4