Re: TGraph2D & Evaluate

I am using root version 5.26-00-64bit, but I will very soon switch to 5.28. Actually I could not try TH2F::Eval because I could not see that class. I get compilation error when I try to use it like:

   histo2D->Eval(0,25)
where I have defined

   TH2F *histo2D = new TH2F("histo2D","histo2D ",66,-400,400,66,-400,400); So should I think TH2F does not support Eval class..?

I instead fitted the histo2D with some TF2 function:

   TF2 *twodFit2 = new TF2("twodFit2",TwoDFit2,-400,400, -400,400,17); and used

   twodFit2->Eval(0,25);
But this is of course not what I want. I want to skip the fitting part since I don't trust enough the functional form and directly interpolate the data. But I want to use the best interpolation scheme that already exists in root instead of writing a new interpolation routine. Does that leave me to only TGraph2d::Interpolate class since there is not TH2F::Eval class?

Thanks for your suggestions.
- Nevzat

> Did you try both TGraph2D::Interpolate and TH2::Eval?
>
> Note that some optimizations in TGraph2D::Interpolate were done in
> version 5.28
>
> Rene Brun
>
>
> On 11/02/2011 04:31, nguler_at_jlab.org wrote:
>> Hello All,
>> I have an intensity distribution in x and y dimensions. The distribution is
>> discrete but I am plotting it with TGraph2D and then using Interpolate class
>> to get the value of the intensity for (x,y) point that is not in the
>> original
>> data. It is not too far off but not perfect either. I am wondering if there
>> is
>> any other class that I am not aware of. I would like to try and compare. Is
>> there Eval class (like the one for TH2F) for TGraph2D?
>>
>> Is the Eval class for TH2F better than the Interpolate class for TGraph2D
>> for
>> this kind of thing, so should I fill a histogram instead of filling
>> TGraph2D?
>>
>> I appreciate you comments.
>>
>> - Nevzat Guler
>> (757) 553-8318
>>
>

• Nevzat Guler (757) 553-8318