Opened 2 years ago

Closed 2 years ago

#22959 closed defect (fixed)

Doctest fix for: series() yields wrong result depending on precision

Reported by: behackl Owned by:
Priority: blocker Milestone: sage-8.0
Component: calculus Keywords:
Cc: rws Merged in:
Authors: Ralf Stephan Reviewers: Benjamin Hackl
Report Upstream: N/A Work issues:
Branch: b121061 (Commits) Commit: b12106198107961e7a2370c34a2b0738471becc3
Dependencies: #22969 Stopgaps:

Description

In the current 8.0.beta5 I get the following:

sage: f = x/(1-x^2)
sage: f.series(x==0, 10)
1*x^2 + 1*x^4 + 1*x^6 + 1*x^8 + Order(x^10)
sage: f.series(x==0, 11)
1*x + 1*x^3 + 1*x^5 + 1*x^7 + 1*x^9 + Order(x^11)

This seems to be a regression from somewhere between sage-7.5 (where the result is still correct) and sage-7.6.

Change History (11)

comment:1 Changed 2 years ago by behackl

As this means that series delivers a mathematically wrong result, I've set the priority to blocker (and this should *really* be fixed before 8.0).

comment:2 Changed 2 years ago by rws

  • Report Upstream changed from N/A to Reported upstream. Developers acknowledge bug.

comment:3 Changed 2 years ago by rws

  • Dependencies set to pynac-0.7.7
  • Report Upstream changed from Reported upstream. Developers acknowledge bug. to Fixed upstream, in a later stable release.

comment:4 Changed 2 years ago by kcrisman

Nice work!

comment:5 Changed 2 years ago by rws

  • Branch set to u/rws/series___yields_wrong_result_depending_on_precision

comment:6 Changed 2 years ago by rws

  • Authors set to Ralf Stephan
  • Commit set to b12106198107961e7a2370c34a2b0738471becc3
  • Dependencies changed from pynac-0.7.7 to #22969
  • Report Upstream changed from Fixed upstream, in a later stable release. to N/A
  • Status changed from new to needs_review
  • Summary changed from series() yields wrong result depending on precision to Doctest fix for: series() yields wrong result depending on precision

New commits:

b12106122959: Doctest fix for: series() yields wrong result depending on precision

comment:7 Changed 2 years ago by behackl

  • Reviewers set to Benjamin Hackl

Thanks a lot for your work, Ralf! Patch LGTM, I'm happy to set this to positive_review as soon as the patchbot tested it.

comment:8 Changed 2 years ago by chapoton

For your information, the best way to have a patchbot run immediatly on your prefered ticket is to launch your own patchbot yourself on this ticket...

comment:9 Changed 2 years ago by behackl

Replying to chapoton:

For your information, the best way to have a patchbot run immediatly on your prefered ticket is to launch your own patchbot yourself on this ticket...

Usually I'd do that, thanks. :-)

However, I'm at a conference and have a very unstable internet connection, so I don't want to build the latest beta on my laptop. And as of a rather unlucky coincidence, my VPN connection to our university servers does not work either, so I also can't start the patchbot we have there.

comment:10 Changed 2 years ago by behackl

  • Status changed from needs_review to positive_review

Running make ptestlong on my laptop lets the test run through, except for being stuck on the has_mathematica()-call in src/sage/doctest/external.py. I don't think that this problem is related to the changes on this ticket, so this is positive_review from me.

comment:11 Changed 2 years ago by vbraun

  • Branch changed from u/rws/series___yields_wrong_result_depending_on_precision to b12106198107961e7a2370c34a2b0738471becc3
  • Resolution set to fixed
  • Status changed from positive_review to closed
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