[boost] Statistics code example

From: Neal D. Becker (nbecker_at_[hidden])
Date: 2003-04-01 08:25:35

Here is an example of a class that can compute 2nd order stats that will work 
for either scalar or complex types.

It could be made slightly more efficient.  It uses abs(), relying on the 
"trick" that abs() is defined for both scalar float and complex.  It could be 
improved by defining our own "norm" function for both scalar float and 
complex.  (Unfortunately for efficiency, complex norm is defined in terms of 
abs, which uses sqrt, on at least some systems (libstdc++)).