Thanks for the clarification and the quick modification.

Snehal

On Wed, Oct 4, 2017 at 7:04 PM, Tiago de Paula Peixoto <[email protected]>
wrote:

> On 04.10.2017 14:26, Snehal Shekatkar wrote:
> > Thanks for the quick reply. It is indeed true that variance should be NaN
> > but assortativity would be zero if I understand it correctly.
>
> No, that is not correct. The variance is not NaN, it is zero. Just look at
> the formula for scalar assortativity: If the variance is zero, the value of
> the coefficient is undefined, as I explained.
>
> > Now, when
> > instead of 'float', I use 'int' as the type for the property map, I do
> get 0
> > value for the assortativity. Thus I guess that the values are wrong and
> it
> > is a bug. Am I right? From your reply, it isn't clear to me if this is a
> bug.
>
> It is not a bug. The reason why you get different answers is due to
> numerical instability. Instead of a variance of zero, what ends up computed
> instead is a very small number due to limited numerical precision.
>
> I've modified the version in git to always return NaN in such cases,
> instead
> of this unstable behavior.
>
> --
> Tiago de Paula Peixoto <[email protected]>
>
>
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>
>


-- 
Snehal M. Shekatkar
Pune
India
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