| Re: Is there a good procedure for Minimum Variance Analysis? [message #58380] |
Tue, 29 January 2008 05:56  |
Wox
Messages: 184
Registered: August 2006
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Senior Member |
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On Mon, 28 Jan 2008 17:54:58 -0800 (PST), "duxiyu@gmail.com"
<duxiyu@gmail.com> wrote:
> I want to perform the Minimum Variance Analysis on a set of magnetic
> field data.
> Is there a good procedure in IDL for this analysis?
>
> Best regards,
> Du
Don't know what it is, but in chapter 8 in this document
http://www.issibern.ch/PDF-Files/analysis_methods_1_1a.pdf
it looks like you have to make a (co)variance matrix from the X,Y and
Z components of the field data
cov(X,X) cov(X,Y) cov(X,Z)
M= cov(Y,X) cov(Y,Y) cov(Y,Z)
cov(Z,X) cov(Z,Y) cov(Z,Z)
Then get the eigenvectors with trired/triql (because M is symmetric).
The eigenvector with the smallest eigenvalue is the boundary normal.
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| Re: Is there a good procedure for Minimum Variance Analysis? [message #58446 is a reply to message #58380] |
Thu, 31 January 2008 19:03  |
duxiyu@gmail.com
Messages: 88
Registered: March 2007
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Member |
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Thanks very much.
It is very helpful.
Du
On Jan 29, 9:56 pm, Wox <nom...@hotmail.com> wrote:
> On Mon, 28 Jan 2008 17:54:58 -0800 (PST), "dux...@gmail.com"
>
> <dux...@gmail.com> wrote:
>> I want to perform theMinimumVarianceAnalysison a set of magnetic
>> field data.
>> Is there a good procedure in IDL for thisanalysis?
>
>> Best regards,
>> Du
>
> Don't know what it is, but in chapter 8 in this documenthttp://www.issibern.ch/PDF-Files/analysis_methods_1_ 1a.pdf
> it looks like you have to make a (co)variancematrix from the X,Y and
> Z components of the field data
>
> cov(X,X) cov(X,Y) cov(X,Z)
> M= cov(Y,X) cov(Y,Y) cov(Y,Z)
> cov(Z,X) cov(Z,Y) cov(Z,Z)
>
> Then get the eigenvectors with trired/triql (because M is symmetric).
> The eigenvector with the smallest eigenvalue is the boundary normal.
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