From: Franco Catalano <franco.catalano_at_nyahnyahspammersnyahnyah>

Date: Thu, 24 Sep 2009 16:10:16 +0200

Date: Thu, 24 Sep 2009 16:10:16 +0200

Hi Dennis,

I have a two-dimensional dataset z(y,x).

I need the one-dimensional autocorrelation function f(delta), where

f(0)=1 and delta is the increasing monotonic vector containing the

distancies between all (y,x) in the domain.

In your example, ra(y, delta_x) and rb(x, delta_y) are the

autocorrelation functions obtained considering, respectively x and y

directions alone, right?

Thank you for your help.

Franco

Il giorno gio, 24/09/2009 alle 07.46 -0600, Dennis Shea ha scritto:

*> Buongiorno
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*>
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*> Perhaps I am misunderstanding the question?
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*>
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*> z(t,x) where t and x are 'named' dimensions of size nt, nx
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*>
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*>
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*> mxlag = 3
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*> ra = esacr(z, mxlag) ; ===> ra(nt,mxlag)
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*> rb = esacr(z(x|:,t|:), mxlag) ; ===> rb(nx,mxlag)
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*>
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*> The latter uses NCL's dimension reordering
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*>
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*> http://www.ncl.ucar.edu/Document/Language/reorder.shtml
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*>
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*> More details are at:
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*> http://www.ncl.ucar.edu/Document/Manuals/Ref_Manual/index.shtml
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*> Click on "Variables"
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*> http://www.ncl.ucar.edu/Document/Manuals/Ref_Manual/NclVariables.shtml#NamedSubscripting
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*>
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*>
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*>
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*>
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*> Franco Catalano wrote:
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*> > Dear ncl developers and users,
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*> > Is there a ncl function to compute the autocorrelation coefficient for a
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*> > two-dimensional (x,y) dataset which considers separations delta at all
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*> > angles?
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*> > The function esacr considers only the rightmost dimension.
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*> > Thank you for any suggestions.
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*> >
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*> > Franco
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*> >
*

-- ____________________________________________________ Eng. Franco Catalano Ph.D. Student D.I.T.S. Department of Hydraulics, Transportation and Roads. Via Eudossiana 18, 00184 Rome Sapienza University of Rome. tel: +390644585218 _______________________________________________ ncl-talk mailing list List instructions, subscriber options, unsubscribe: http://mailman.ucar.edu/mailman/listinfo/ncl-talkReceived on Thu Sep 24 2009 - 08:10:16 MDT

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