Re: quadl can't integrate sin or cos over a period

[LUK ShunTim]

Dmitri A. Sergatskov wrote:
> On Mon, Jul 7, 2008 at 11:41 PM, Adam Higuera <address@hidden> wrote:
>> When I enter the command:
>>
>> quadl(@sin, 0, 2*pi)
>>
>> octave 3.0.1 under Fedora 9 hangs and fails to produce a result.  However,
>>
> 
> Perhaps it is a bug in the algorithm itself. In any case it does not
> really hangs,
> it just take a very long time to finish. You can speed it up by specifying
> tolerance :
> 
> octave:12> tic; x=quadl(@sin, 0, 2*pi, 1e-2); toc
> Elapsed time is 0.6039 seconds.
> octave:13> x
> x =  1.3878e-16
> octave:14> tic; x=quadl(@sin, 0, 2*pi, 1e-3); toc
> Elapsed time is 2.542 seconds.
> octave:15> x
> x =  1.1102e-16
> octave:16> tic; x=quadl(@sin, 0, 2*pi, 1e-4); toc
> Elapsed time is 7.278 seconds.
> octave:17> x
> x =  1.1102e-16
> octave:18> tic; x=quadl(@sin, 0, 2*pi, 1e-5); toc
> Elapsed time is 28.99 seconds.
> octave:19> x
> x =  1.1102e-16
> octave:20>
> 
> Dmitri.
> --

The integral of sine from 0 to 2\pi is, of course, 0. It seems we have a
variant of another recent thread. :-)

Regards,
ST
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