Opened 5 years ago

Closed 4 years ago

Last modified 4 years ago

#22005 closed defect (fixed)

sum(1/((2*n+1)^2-4)^2, n, 0, oo, algorithm='maxima') is wrong

Reported by: slabbe Owned by:
Priority: major Milestone: sage-7.6
Component: symbolics Keywords: maxima
Cc: Merged in:
Authors: Reviewers:
Report Upstream: Fixed upstream, in a later stable release. Work issues:
Branch: Commit:
Dependencies: #18920 Stopgaps:

Status badges

Description (last modified by slabbe)

From ​ask.sagemath.org: 

sage: n = var('n')
sage: sum(1/((2*n+1)^2-4)^2, n, 0, oo)
1/64*pi^2 - 1/12
sage: sum(1/((2*n+1)^2-4)^2, n, 0, oo, algorithm='maxima')
1/64*pi^2 - 1/12

but correct answer is 1/64*pi^2. SymPy (with #22004) and Mathematica do it right: 

sage: sum(1/((2*n+1)^2-4)^2, n, 0, oo, algorithm='mathematica')
1/64*pi^2
sage: sum(1/((2*n+1)^2-4)^2, n, 0, oo, algorithm='sympy')
1/64*pi^2

I am using version: 

$ sage -standard | grep maxima
maxima..................................5.35.1.p2 (5.35.1.p2)

See #18920 for the ticket updating maxima version.

Change History (8)

comment:1 Changed 5 years ago by slabbe

  • Description modified (diff)

comment:2 Changed 5 years ago by slabbe

  • Description modified (diff)

comment:3 Changed 5 years ago by slabbe

  • Report Upstream changed from N/A to Fixed upstream, in a later stable release.

Seems to be fixed upstream or "perhaps an interaction with some flags that Sage is setting" according to Robert Dodier:

​https://sourceforge.net/p/maxima/bugs/3236/#7b13/aab3

comment:4 Changed 5 years ago by dimpase

  • Dependencies set to #18920
  • Milestone changed from sage-7.5 to sage-7.6

this is to be fixed in #18920; this bug does not appear in the currently tested configuration of ECL-16.1.3+Maxima 5.39.0; this ticket should be closed after #18920 is done.

comment:5 Changed 4 years ago by slabbe

  • Status changed from new to needs_review

comment:6 Changed 4 years ago by slabbe

  • Status changed from needs_review to positive_review

This is fixed in 8.0.beta11.

comment:7 Changed 4 years ago by vbraun

  • Resolution set to fixed
  • Status changed from positive_review to closed

comment:8 Changed 4 years ago by slabbe

Just to say that a doctest is already testing this issue:

​https://github.com/sagemath/sage/blob/develop/src/sage/calculus/calculus.py#L569

It was added in #22004 and updated during the upgrade to maxima 5.39.

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