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Re: gauss chebychew quadrature in integration package
From: |
Ben Abbott |
Subject: |
Re: gauss chebychew quadrature in integration package |
Date: |
Sun, 22 Jun 2008 18:08:45 -0400 |
On Jun 22, 2008, at 3:59 PM, Thomas Plehn wrote:
my whole octave session with all user input is shown on the picture
accessible under the posted link
----- Original Message ----- From: "Ben Abbott" <address@hidden>
To: "Thomas Plehn" <address@hidden>
Cc: <address@hidden>
Sent: Sunday, June 22, 2008 9:14 PM
Subject: Re: gauss chebychew quadrature in integration package
On Jun 22, 2008, at 2:54 PM, 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?
Can you post a bit more information. Perhaps a short script
illustrating specifically what you did?
Ben
ok,
I've not used the integration package before, but modified you example
to create a simpler version.
> pkg load integration
> function y = f (x)
> y = 1;
> endfunction
> cquadnd ("f", 0, 1, 1)
ans = 1.5708
The answer is obviously wrong (should be 1), and as far as I can tell
you are using cquadnd in manner consistent with the documentation.
Thus, it does look like a bug to me.
To report the bug, please go to the link below
https://lists.sourceforge.net/lists/listinfo/octave-dev
Ben