| qsimp, qromb, qromo [message #39628] |
Thu, 03 June 2004 12:46  |
gnarloo
Messages: 14
Registered: June 2004
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Junior Member |
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Dear all,
I'm new to this newsgroup so first of all, hello everybody!
The problem i encountered is the following:
I tried to use
qsimp and qromb to integrate a couple of functions (scattering
problems, nothing special) but the system crashes..
I tried to integrate cos(x) between 0 and pi (the result is obviously
zero)
and these functions give out some kind of error message but not the
result..
so i turned to write the code myself as i used to do when i was an
undrgraduate student using old riemann sums and old fortran, but as
this approach is a bit time-consuming i have one question:
is there any trick I can use or these functions only sometimes work?
(for example if you integrate sin(x) on the same interval as above
they give out
the right result.
Personally I can't believe the problem is in the algorithm (Simpson
rule works, Romberg method I don't know it)...
thanks very much indeed for your help
bye
michael
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| Re: qsimp, qromb, qromo [message #39794 is a reply to message #39628] |
Thu, 10 June 2004 12:17  |
K. Bowman
Messages: 330
Registered: May 2000
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Senior Member |
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In article <b3eff7b0.0406101021.7f3835ef@posting.google.com>,
gnarloo@libero.it (michele) wrote:
> dear craig thanks very much for your answer
> and for all the routines you made available on your web site.
>
> just one more favour,
> do you know an alternative to IDL standard routine to find eigenvectors and
> eigenvalues of a complex symmetric matrix (real on the diagonal and
> complex conjugate elsewhere??)
> it sometimes crashes...
Are you using LA_EIGENQL or the older EIGENQL? LA_EIGENQL is based on
LAPACK and should be quite robust.
Ken Bowman
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