RE: chi2 function and delta (dirac) function

From: Marc Escalier <escalier_at_lal.in2p3.fr>
Date: Tue, 28 Sep 2010 23:33:00 +0200

wonderful Amnon

thank you so much
for your great expertise

it helps me a lot

regards

---

On Tue, 28 Sep 2010, Amnon Harel wrote:

>
> Dear Marc,
>
> TMath::GammaDist with a shape parameter (called gamma in ROOT, k
> in wikipedia) n/2 and a scale parameter (called beta in ROOT, theta
> in wikipedia) of 2, gives you a chi^2 distribution with n degrees of freedom.
>
> http://root.cern.ch/root/html/TMath.html
> is a useful page for finding such tools (though there's much more
> available if you dig even deeper).
>
> The Dirac delta function is not a function. Without some framework
> for specifying integrands and operations on them, how can it be
> represented in C++? So for the bonus, I'll go with "no".
>
>  cheers,
>  Amnon
>
>
> -----Original Message-----
> From: owner-roottalk_at_root.cern.ch on behalf of Marc Escalier
> Sent: Tue 28-Sep-10 3:15 PM
> To: roottalk_at_lxroot01.cern.ch
> Subject: [ROOT] chi2 function and delta (dirac) function
>
> Dear rooters,
>
> would you know if there exist a existing chi2 function in root
>
> (i wish to draw the chi2 function)
>
> Do i need to write it by hand in a TF1 ?
>
> as a bonus question, would you know if the "Dirac" delta function exists ?
>
> thank you
>
>
>
>
Received on Tue Sep 28 2010 - 23:33:05 CEST