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

[anonymous]

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>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/