Opened 7 years ago

Closed 7 years ago

#14751 closed defect (fixed)

Regression in representation of CombinatorialFreeModules (introduced #13735)

Reported by: agd Owned by: agd
Priority: major Milestone: sage-5.11
Component: misc Keywords:
Cc: vittucek novoselt jdemeyer Merged in: sage-5.11.beta2
Authors: John Palmieri Reviewers: Andrew Gainer-Dewar
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:


The patch applied by ticket #13735 changes the behavior of the repr_lincomb method in misc/ so that it now evaluates the comparison "c < 0" for every coefficient. However, since this method is called by CombinatorialFreeModule?, which can create lienar combinations whose coefficients are elements of arbitrary rings, this comparison is not always mathematically meaningful.

For example, in the code I submitted in #14347, I build a CombinatorialFreeModule? whose basis is a specified finite group G and whose coefficients are elements of a CycleIndexSeriesRing?. In 5.9, this was perfectly functional; in 5.10-rc2, with the new patch, any call to _repr_ on an element of this CombinatorialFreeModule? results in a NotImplementedError? because of this comparison.

Attachments (1)

trac_14751.patch (1.5 KB) - added by jhpalmieri 7 years ago.

Download all attachments as: .zip

Change History (5)

comment:1 Changed 7 years ago by jhpalmieri

  • Authors set to John Palmieri
  • Status changed from new to needs_review

Here is an attempt at a patch. It seems to work with the patch at #14347.

Changed 7 years ago by jhpalmieri

comment:2 Changed 7 years ago by agd

  • Status changed from needs_review to positive_review

This seems to do the trick, and the code looks good to me! All doctests pass on my system, including those added in #14347. Thanks for taking the time to look at this.

comment:3 Changed 7 years ago by jdemeyer

  • Reviewers set to Andrew Gainer-Dewar

comment:4 Changed 7 years ago by jdemeyer

  • Merged in set to sage-5.11.beta2
  • Resolution set to fixed
  • Status changed from positive_review to closed
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