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## [Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating

**From**: |
anonymous |

**Subject**: |
[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods |

**Date**: |
Wed, 15 Jan 2020 05:59:15 -0500 (EST) |

**User-agent**: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0 |

URL:
<https://savannah.gnu.org/bugs/?57603>
Summary: quadv gives wrong results integrating sin^2 or cos^2
on multiple of 8 periods
Project: GNU Octave
Submitted by: None
Submitted on: Wed 15 Jan 2020 10:59:14 AM UTC
Category: Octave Function
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Incorrect Result
Status: None
Assigned to: None
Originator Name: Olivier Amoignon
Originator Email: address@hidden
Open/Closed: Open
Discussion Lock: Any
Release: 4.2.2
Operating System: GNU/Linux
_______________________________________________________
Details:
Tested with version 4.2.2 under Ubuntu 18.04LTS and version 3.8.2 under Centos
7:
examples are
quadv(@(t)sin(t).^2,0,8*pi)
which gives 8.0412e-30 whereas
quadv(@(t)sin(t).^2,0,10*pi)
gives 15.708
Another example is
quadv(@(t)cos(t).^2,0.5*pi,8.5*pi)
which gives 2.2364e-29 instead of 12.566, the result obtained by quad or
quadgk.
_______________________________________________________
Reply to this item at:
<https://savannah.gnu.org/bugs/?57603>
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**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**,
*anonymous* **<=**
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Kai Torben Ohlhus*, `2020/01/15`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Kai Torben Ohlhus*, `2020/01/15`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Rik*, `2020/01/15`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Olivier Amoignon*, `2020/01/16`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Olivier Amoignon*, `2020/01/16`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Rik*, `2020/01/16`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Rik*, `2020/01/17`
**[Octave-bug-tracker] [bug #57603] quadv gives wrong results integrating sin^2 or cos^2 on multiple of 8 periods**, *Kai Torben Ohlhus*, `2020/01/21`