eofunc & eofunc_varimax

From: Paulo de Melo <pmelo_at_nyahnyahspammersnyahnyah>
Date: Tue, 11 Jul 2006 04:00:58 +0100


I having problems with the EVAL attribute of the EOFUNC funtion. The
eigenvalues are different from those computed with the EOFCOV
function, which are correct. The % explained variance given by the PCVAR
attribute, which had a problem in NCL 4.2.0.a032, are correct. Note that I'm
now running NCL a033 which fixed the @pcvar bug.

I'm also getting errors with the PCVAR_VARIMAX attribute of the EOFUNC_VARIMAX
function: the variances have absurd results and do not sum to 100% (when I
compute all the EOFs). Interestingly, when I rescale the EOFs, prior to the
rotation operation, they do sum to 100% but they are not in decreasing
order. (The scaling used is the one that results in EOF loadings equal to the
correlations between the data and the PC, that is, each EOF loading is
multiplied by the square root of the eigenvalue and, if the covariance matrix
was used, divided by the standard deviation of the data.)

The EOFUN_VARIMAX documentation about the % explained variance is
contradictable: in the RETURN VALUE part it is said that it is "returned as
an attribute of the returned value called pcvar_varimax" and in the
DESCRIPTION part it is said that it "is not returned".

Please help,

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Received on Mon Jul 10 2006 - 21:00:58 MDT

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