[ROOT] EigenValues

From: Dr. John Krane (jkrane@netzero.com)
Date: Tue Sep 16 2003 - 23:10:56 MEST 

Hi,

I'm trying to find the eigen-stuff of a matrix.  Following the info in 
the root/test/*.cxx files and what I can find online, I'm doing:

   TMatrix tcovmat[NBINS][NBINS];

   for (Int_t i=1;i<NBINS;i++) {
     for (Int_t j=1;j<=i;j++) {
	... blah blah computing the elements of the matrix...
       tcovmat[i][j]=aaa;
       tcovmat[j][i]=aaa; //symmetric
     }
   }
   TVector eigenvalues[NBINS];
   TMatrix eigenvectors[NBINS][NBINS];
   eigenvectors = tcovmat.EigenVectors(eigenvalues);

But this code makes the compiler unhappy:

find_vr.C:237: request for member `EigenVectors' in `tcovmat', which is 
of non-aggregate type `TMatrix[((NBINS - 1) + 1)][((NBINS - 1) + 1)]'

This message seems a bit cryptic to me, and I thought I was using the 
method correctly.  Could somebody please tell me what I'm doing wrong?

	- John

-- 

Dr. John Krane
jkrane@netzero.com

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