bug in the way vectors are created for submodules of free modules

[williamstein]

Let R be a ring with fraction field K.

When you create a R-submodule of K^n (with K!=QQ) the vectors 
are created in the ring R not the fraction field.  This breaks things 
when the submodule is not in R^n.

Fixed by #11751.

CC: @mminzlaff

Component: linear algebra

Reviewer: William Stein, Moritz Minzlaff

Issue created by migration from https://trac.sagemath.org/ticket/11034

[mminzlaff]

comment:3

The new version adds a doctest (and is slightly modified to make the doctest work).

The only doctest failure I received was related to the startup time as checked by startup.py. Curiously enough, replicating the same test on my local machine returned True. (Replicating as in: not running the doctest itself as it always returns True when not on sage.math.)

[mminzlaff]

comment:4

Apply trac_11034.v2.patch

[mminzlaff]

Author: William Stein, Moritz Minzlaff

[koffie]

comment:6

This patch fails to apply to 4.7.2.alpha2

md:sage maarten$ mhg qim -P https://github.com/sagemath/sage/files/ticket11034/trac_11034.v2.patch.gz
adding trac_11034.v2.patch to series file
applying trac_11034.v2.patch
patching file sage/modules/free_module.py
Hunk #1 FAILED at 4902
1 out of 1 hunks FAILED -- saving rejects to file sage/modules/free_module.py.rej
patching file sage/modules/free_module_element.pyx
Hunk #3 succeeded at 3356 with fuzz 1 (offset 701 lines).
patch failed, unable to continue (try -v)
patch failed, rejects left in working dir
errors during apply, please fix and refresh trac_11034.v2.patch

But there was some stupid duplicate of work so there is another ticket wich fixes the same problem at #11751
so if that one gets positive review and merged we can close this one.

[koffie]

Work Issues: rebase

[mminzlaff]

comment:7

Since #11751 received a positive review and was merged in 4.7.2, maybe this ticket can be closed? (I also checked the test in the docstring of this patch and it passes in Sage 5.0.)

[williamstein]

comment:8

I can confirm that your examples work fine in sage-5.0. So this can be closed. The proper way to do that is "positive review".

[williamstein]

Reviewer: William Stein

[jdemeyer]

Changed work issues from rebase to none

[jdemeyer]

Changed author from William Stein, Moritz Minzlaff to none

[jdemeyer]

Changed reviewer from William Stein to William Stein, Moritz Minzlaff