[PD] variance from mapping library

[Oded Ben-Tal]

>
> 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.
>

I am getting a negative number occasionally.
Oded