gauss chebychew quadrature in integration package

[David Bateman]

Thomas Plehn wrote:
> http://img28.picoodle.com/img/img28/4/6/22/f_quadraturem_a5f90c3.png
>
> hello,
> I have tried to integrate a simple function in octave using the integration 
> package.
> the function is f(x,y)=x^2*sin(y)
> the integration limits for both x and y are from 0 to 1.
> the result should be (1-cos(1))/3 = 0,15323
> this result is yielded by quadndg, gquadnd
> but cquadnd yield a different result
>
> should this be considered as a bug? 
>
> _______________________________________________
> Help-octave mailing list
> Help-octave at octave.org
> https://www.cae.wisc.edu/mailman/listinfo/help-octave
>
>   
For what its worth, with 3.1.x (I.E. the head of the repository) and the
dblquad function I added I get

octave:1> dblquad (@(x,y) x.^2 .* sin (y), 0, 1, 0, 1, 1e-6, @quadgk)
ans =  0.15323
octave:2> dblquad (@(x,y) x.^2 .* sin (y), 0, 1, 0, 1, 1e-6, @quadv)
ans =  0.15323

Yes I suspect its a bug you found, though if you can look further at the
cquadnd function for bugs then that would help as I', not sure this will
be fixed otherwise.


D.


-- 
David Bateman                                David.Bateman at motorola.com
Motorola Labs - Paris                        +33 1 69 35 48 04 (Ph) 
Parc Les Algorithmes, Commune de St Aubin    +33 6 72 01 06 33 (Mob) 
91193 Gif-Sur-Yvette FRANCE                  +33 1 69 35 77 01 (Fax) 

The information contained in this communication has been classified as: 

[x] General Business Information 
[ ] Motorola Internal Use Only 
[ ] Motorola Confidential Proprietary