[ROOT] means from TPrincipal

From: Michael Gold (gold@higgs.phys.unm.edu)
Date: Tue Apr 08 2003 - 02:09:38 MEST 

Dear roottalk:

I am using TPrincipal for a 2D array. 

If I init TPrincipal as 
 TPrincipal * principal = new TPrincipal(2,"N");
then the first mean is incorrect.  If I init it as 
 TPrincipal * principal = new TPrincipal(3,"N");
then you can see what is happening:


 Variable #  | Mean Value |   Sigma    | Eigenvalue
-------------+------------+------------+------------
           0 |  1.522e+04 |   2.21e-11 |     0.5404 
           1 |    0.01277 |      1.031 |     0.3331 
           2 |    0.01511 |       1.06 |     0.1265 

where the correct means are,
 mean 1 = 0.0127681 mean 2 = 0.0151134

bug, or am I incorrectly using this class?

thanks,
Michael Gold

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