[PD] variance from mapping library

[Mathieu Bouchard]

On Wed, 18 Mar 2009, Oded Ben-Tal wrote:

> when using variance (from mapping library) - I get negative numbers. 
> Since variance is supposed to be always positive and I don't see 
> anything wrong in the way the abstraction is done, I presume there is 
> something I'm missing. My impression is that small changes in the input 
> translate to negative 'variance'

Is it really a negative number, or is it more like 9.74915e-05 ? In the 
latter case, only the exponent is negative, which means 
9.74915/10/10/10/10/10 = 0.0000974915, whereas with a plus sign like 
1.2e+06 would mean 1.2*10*10*10*10*10*10 = 1200000.

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