Opened 5 years ago
Closed 4 years ago
#21801 closed defect (fixed)
incorrect summation
Reported by:  kcrisman  Owned by:  

Priority:  major  Milestone:  sage8.0 
Component:  calculus  Keywords:  
Cc:  Merged in:  
Authors:  Thierry Monteil  Reviewers:  Travis Scrimshaw 
Report Upstream:  Completely fixed; Fix reported upstream  Work issues:  
Branch:  4b525bb (Commits, GitHub, GitLab)  Commit:  4b525bb059e2986d6c8cc6c822c1abca730e701c 
Dependencies:  Stopgaps: 
Description
Reported here:
sage: sum(1/((n+1)*(2*n1)), n, 0, 1000).n() 0.205068171626375 sage: sum(1/((n+1)*(2*n1)), n, 0, 10000).n() 0.204618542543703 sage: sum(1/((n+1)*(2*n1)), n, 0, 100000).n() # seems to be converging 0.204573546255870 sage: sum(1/((n+1)*(2*n1)), n, 0, oo).n() # but not to this number 1.09345743518226 sage: sum(1/((n+1)*(2*n1)), n, 0, oo) 2/3*log(2)  14/9 sage: sum(1/((n+1)*(2*n1)), n, 0, oo).n()  sum(1/((n+1)*(2*n1)), n, 0, 10000).n() 0.888838892638556
Change History (7)
comment:1 Changed 5 years ago by
 Report Upstream changed from Not yet reported upstream; Will do shortly. to Reported upstream. No feedback yet.
comment:2 Changed 5 years ago by
 Report Upstream changed from Reported upstream. No feedback yet. to Fixed upstream, but not in a stable release.
comment:3 Changed 4 years ago by
 Branch set to u/tmonteil/incorrect_summation
comment:4 Changed 4 years ago by
 Commit set to 7a36941ede54986bfa4dbc2b35d4aa3f0f8e693d
 Milestone changed from sage7.5 to sage8.0
 Report Upstream changed from Fixed upstream, but not in a stable release. to Completely fixed; Fix reported upstream
 Status changed from new to needs_review
The fix seems to have entered Sage now. So i am just ading a doctest to prevent the bug to reappear.
comment:5 Changed 4 years ago by
 Commit changed from 7a36941ede54986bfa4dbc2b35d4aa3f0f8e693d to 4b525bb059e2986d6c8cc6c822c1abca730e701c
Branch pushed to git repo; I updated commit sha1. New commits:
4b525bb  #21801 : a doctest to prevent the bug to reappear.

comment:6 Changed 4 years ago by
 Reviewers set to Travis Scrimshaw
 Status changed from needs_review to positive_review
LGTM.
comment:7 Changed 4 years ago by
 Branch changed from u/tmonteil/incorrect_summation to 4b525bb059e2986d6c8cc6c822c1abca730e701c
 Resolution set to fixed
 Status changed from positive_review to closed
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Tracked upstream at https://sourceforge.net/p/maxima/bugs/3236/.