| orthogonal distance regression [message #45959] |
Mon, 24 October 2005 08:59  |
Steve.Morris
Messages: 17
Registered: November 2002
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Junior Member |
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Does anybody know if somewhere on the net there's a package to perform
orthogonal distance regression ?
I have found odrpack from netlibe.org, but I was just wondering whether
an already idl cocked package exists...
More generally, if anybody has already used such a technique, advices
or tutorial are welcome :)
Thanks in advance!
S.
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| Re: orthogonal distance regression [message #46026 is a reply to message #45959] |
Tue, 25 October 2005 08:37  |
Craig Markwardt
Messages: 1869
Registered: November 1996
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Senior Member |
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Steve.Morris@libero.it writes:
> Does anybody know if somewhere on the net there's a package to perform
> orthogonal distance regression ?
>
> I have found odrpack from netlibe.org, but I was just wondering whether
> an already idl cocked package exists...
>
> More generally, if anybody has already used such a technique, advices
> or tutorial are welcome :)
ODR has been discussed before on this newsgroup. I'm not aware of any
package in IDL. A curve fitting program like MPFIT would need to be
modified pretty significantly to accomodate the ODR aspects. [*] In
the past I've referred people to ODRPACK and they've been very happy
(except that it's not native IDL).
Craig
[*] - actually, the changes are not huge. It might be an interesting
project for someone.
--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@REMOVEcow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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| Re: orthogonal distance regression [message #46040 is a reply to message #45959] |
Tue, 25 October 2005 00:38 |
Paolo Grigis
Messages: 171
Registered: December 2003
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Senior Member |
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For *linear* regression, there exist sixlin.pro by W. Landsman
from the IDL astronomy library:
http://idlastro.gsfc.nasa.gov/ftp/pro/math/sixlin.pro
It computes 6 different kind of linear regression (x vs. y,
y vs. x, orthogonal etc.).
The programs implements the procedure described in
Isobe, Feigelson, Akritas, and Babu, Astrophysical Journal
Vol. 364, p. 104 (1990)
which has a nice overview of the effect of the different
linear regression methods for data sets where the spread
of the data is large. This of course apply not only to
astronomy but to other fields as well.
Ciao,
Paolo
Steve.Morris@libero.it wrote:
> Does anybody know if somewhere on the net there's a package to perform
> orthogonal distance regression ?
>
> I have found odrpack from netlibe.org, but I was just wondering whether
> an already idl cocked package exists...
>
> More generally, if anybody has already used such a technique, advices
> or tutorial are welcome :)
>
> Thanks in advance!
> S.
>
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