[Octave-bug-tracker] [bug #46349] dblquad/triplequad - periodic functions over the whole period

[Nicholas Jankowski]

Follow-up Comment #10, bug #46349 (project octave):

looking at the integrators and came across this. in 4.2.1 dblquad works
quickly for all but quadcc on the test in Comment #1.  It actually does finish
with quadcc, but takes quite some time. since quadcc is the default, dblquad
without specifying the integrator takes a long time.


>> tic;dblquad(@(x,y) sin(2 * pi * x ) * sin(2 * pi * y),0,1,0,1, [],
'quadgk');toc
Elapsed time is 0.188 seconds.

>> tic;dblquad(@(x,y) sin(2 * pi * x ) * sin(2 * pi * y),0,1,0,1, [],
'quadv');toc
Elapsed time is 0.072 seconds.

>> tic;dblquad(@(x,y) sin(2 * pi * x ) * sin(2 * pi * y),0,1,0,1, [],
'quadl');toc
Elapsed time is 0.0909998 seconds.

>> tic;dblquad(@(x,y) sin(2 * pi * x ) * sin(2 * pi * y),0,1,0,1, [],
'quadcc');toc
Elapsed time is 49.752 seconds.

>> tic;dblquad(@(x,y) sin(2 * pi * x ) * sin(2 * pi * y),0,1,0,1);toc
Elapsed time is 48.5679 seconds.


so it's incorrect to say that it doesn't terminate, but a factor of 200-300x
in computation time is surely not ideal. 

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?46349>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/