MATLAB Central Newsreader - how to integrate a oscillating function with matlab numetically?

how to integrate a oscillating function with matlab numetically?

wang wang — Thu, 05 Jun 2008 07:48:02 -0400

Hi~everyone, I have a oscillating function, but I don't
know how to integrate it with matlab, the results given by
the matlab function quad and quad8 are not ideal. Is there
a special function in matlab to do this kind of
integration .

Re: how to integrate a oscillating function with matlab numetically?

John D'Errico — Thu, 05 Jun 2008 09:12:03 -0400

"wang wang" <pligly@gmail.com> wrote in message
<g285ni$27j$1@fred.mathworks.com>...
> Hi~everyone, I have a oscillating function, but I don't
> know how to integrate it with matlab, the results given by
> the matlab function quad and quad8 are not ideal. Is there
> a special function in matlab to do this kind of
> integration .

No. Sorry.

A completely general oscillating function may
be difficult to integrate, depending on the
size of the range and the number of periods
contained within it. Of course, the last time
someone asked this question, they were trying
to integrate over the infinite real line. I hope
that you are not also trying to use an adaptive
numerical tool to integrate over an infinite
domain.

John

Re: how to integrate a oscillating function with matlab numetically?

wang wang — Thu, 05 Jun 2008 13:35:03 -0400

"John D'Errico" <woodchips@rochester.rr.com> wrote in
message <g28al3$5dh$1@fred.mathworks.com>...
> "wang wang" <pligly@gmail.com> wrote in message
> <g285ni$27j$1@fred.mathworks.com>...
> > Hi~everyone, I have a oscillating function, but I
don't
> > know how to integrate it with matlab, the results
given by
> > the matlab function quad and quad8 are not ideal. Is
there
> > a special function in matlab to do this kind of
> > integration .
>
> No. Sorry.
>
> A completely general oscillating function may
> be difficult to integrate, depending on the
> size of the range and the number of periods
> contained within it. Of course, the last time
> someone asked this question, they were trying
> to integrate over the infinite real line. I hope
> that you are not also trying to use an adaptive
> numerical tool to integrate over an infinite
> domain.
>
> John

John, Thank you for reply!
Actually, it's true, i am trying to integrate an
oscillating function over an infinite interval. What i
have known is that this function is integrable.Is it
possible to use quadl to do this work? thanks!