From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>

Date: Thu Jul 25 2013 - 16:43:42 MDT

Date: Thu Jul 25 2013 - 16:43:42 MDT

[1] Sorry, I have no experience with "squared covariance"

[2] anomalies: I would make the original input (x, y) be anomalies

Then project the various 'right/left' arrays onto the original

anomaly data. As in [1]: no experience with this.

[3[ if it takes too much time, input a smaller subset of the data

for testing.

On 7/24/13 2:53 PM, Ahmad Farsyud wrote:

*> Thank you expert, for your kind hints. this function consumed so much time
*

*> to work in ncl, though!! One last question how could i calculate a squared
*

*> covariance (sc) for each svd analysis in each mode? and also how could i
*

*> get the values in anomalies from each mode, in eof is really clear how to
*

*> do that.
*

*>
*

*> thank you so much,
*

*>
*

*> AF
*

*>
*

*>
*

*>
*

*>
*

*> On Thursday, July 18, 2013, Dennis Shea wrote:
*

*>
*

*>> ??? 2d fields [timexlatxlon] <=== this is 3d
*

*>>
*

*>>
*

*>> [1]
*

*>> Let x(time,lat,lon) ; sizes ==> (ntim,nlat,mlon)
*

*>> y(time,lat,lon)
*

*>>
*

*>> nxy = nlat*mlon
*

*>> ; reorder so time varying fastest
*

*>> X = x(lat|:,lon|:,time|:) ; sizes ===>(nlat,mlon,ntim)
*

*>> X2 = onedtond( ndtooned(X), (/ nxy, ntim /) ) ; (:,:)
*

*>>
*

*>> Y = ...
*

*>> Y2 = ...
*

*>> delete( [/x,y,X,Y/])
*

*>>
*

*>> nsvd = ...
*

*>>
*

*>> svLeft = new((/nsvd,nxy/),typeof(x)) ; pre-allocate space
*

*>> svRight = new((/nsvd,nxy/),typeof(x))
*

*>>
*

*>> pc = svdcov_sv(X2,Y2,nsvd,svLeft,**svRight)
*

*>>
*

*>> printVarSummary(pc)
*

*>>
*

*>>
*

*>> [2]
*

*>> No. You can write your own plot code.
*

*>>
*

*>> do ns=0,nsvd-1
*

*>> left = onedtond(svLeft(ns,:) , (/nlat,mlon/) ) ; reshape
*

*>> rght = onedtond(svRight(ns,:), (/nlat,mlon/) )
*

*>>
*

*>> left!0 = "lat"
*

*>> left!1 = "lon"
*

*>> left&lon = x&lon
*

*>> left&lat = x&lat
*

*>>
*

*>> rght!0 = "lat"
*

*>> rght!1 = "lon"
*

*>> rght&lon = x&lon
*

*>> rght&lat = x&lat
*

*>>
*

*>> ; plot code here
*

*>>
*

*>>
*

*>> end do
*

*>>
*

*>> [3] lags .. the following is untested
*

*>>
*

*>> ntim = dimsizes(x&time)
*

*>>
*

*>> nlag = 3
*

*>>
*

*>> nxStrt = 0
*

*>> nxLast = ntim-1-nlag
*

*>> nxTime = nxLast-nxStrt+1
*

*>> X = x(lat|:,lon|:,time|nxStrt:**nxLast) ; sizes ===>(nlat,mlon,ntim)
*

*>> X2 = onedtond( ndtooned(X), (/ nxy, nxTime /) ) ; (:,:)
*

*>>
*

*>> nyStrt = nlag
*

*>> nyLast = ntim-1
*

*>> nyTime = nyLast-nyStrt+1
*

*>> Y = y(lat|:,lon|:,time|nyStrt:**nyLast) ; sizes ===>(nlat,mlon,ntim)
*

*>> Y2 = onedtond( ndtooned(X), (/ nxy, nyTime /) ) ; (:,:)
*

*>>
*

*>> X2 leads Y2 by 'nlag' time steps
*

*>>
*

*>> ++++++++++++++++++++++++++++++**+++++++++++++
*

*>> ++++++++++++++++++++++++++++++**+++++++++++++
*

*>> NOTE: I do not have the time for multiple emails.
*

*>> You will have to figure the rest out yourself.
*

*>> ++++++++++++++++++++++++++++++**+++++++++++++
*

*>> ++++++++++++++++++++++++++++++**+++++++++++++
*

*>>
*

*>> On 07/11/2013 12:31 AM, Ahmad Farsyud wrote:
*

*>>
*

*>>> Hi NCL,
*

*>>>
*

*>>> I have several question regarding this function "svdcov_sv":
*

*>>> http://www.ncl.ucar.edu/**Document/Functions/Built-in/**svdcov_sv.shtml<http://www.ncl.ucar.edu/Document/Functions/Built-in/svdcov_sv.shtml>
*

*>>> 1. How could I apply this function for 2d fields [timexlatxlon]
*

*>>> 2. Is there any example of the display output using this function in NCL?
*

*>>> 3. One can give me suggestion , what should I do if I want to use svd
*

*>>> for time-lagged analysis?
*

*>>>
*

*>>> Thank you,
*

*>>> - AF
*

*>>>
*

*>>>
*

*>>> ______________________________**_________________
*

*>>> ncl-talk mailing list
*

*>>> List instructions, subscriber options, unsubscribe:
*

*>>> http://mailman.ucar.edu/**mailman/listinfo/ncl-talk<http://mailman.ucar.edu/mailman/listinfo/ncl-talk>
*

*>>>
*

*>>>
*

*>>
*

*>
*

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Received on Thu Jul 25 16:43:53 2013

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