Use own TF1 in TTree::Draw

ROOT
1

Hello,
I am wondering if it is possible to use a TF1 which is evaluated at a certain x value in the TTree::Draw function:
Something like:

TF1* pol2 = new TF1("fit","pol2",0,1024)
pol2->FixParameter(0,0)
pol2->FixParamter(1,1)
pol2->FixParamter(2,1)
tree->Draw("fit(x)")

I found a very old discussion in root.cern.ch/root/roottalk/roottalk03/3458.html
In this message Philippe is referring to the global functions.
If there is no other way, is it possible to add a function to global functions, such that the TTree::Draw recognizes the function?
Thanks,
Felix

2

See “Drawing a user function accessing the TTree data directly” in the TTree::Draw method description.

3

A small remark: the documentation which is actively maintained is the Doxygen one.
In this case, the correct link would be TTree::Draw.

4

Your new fantastic web pages open in something like 10 to 15 seconds and they even tend to freeze my firefox when opening. The old ones are there in below 0.5 second. That really makes a difference (especially if you need to open several pages and/or you follow embedded links).
Moreover, your new web pages are valid for ROOT 6 only, while the old ones are for ROOT 5 (and so, assuming a certain level of “backward compatibility”, they can also be used for ROOT 6).

5

Dear Pepe,

I noticed, too, a while back, and I measured. It takes an enormous time for our doxygen pages to show, compared to the THtml pages.

Still, for instance on Chrome they get painted very early, which is what counts. A firefox plugin famous for colliding with Doxygen pages is Ghostery. You don’t happen to have that installed?

Nonetheless I’m looking for a fix: we have a nice, really fast web server. I have monitoring running on it; from within Europe, the static web pages load within 0.1 second. But somehow doxygen spoils it.

If we have someone who cares and has a hint about what to try then please let me know!

Cheers, Axel.

6

Hi,

Okay, first step: reduce the page size. For TClass, doxygen produces 1.89MB compared to 0.26MB for THtml. That’s a factor 7.

I have removed the “referenced by” sections, that kills 1MB. Yikes.

Could you check again tomorrow and let us know whether the load times have noticeably improved?

Cheers, Axel.

7

Seems better now -> let’s say 5 seconds …
Could you also, please, remove the “Reimplemented in” section (but do not remove “Reimplemented from”, if possible).

8

I will try to find the option(s) allowing to do that. A quick search didn’t give me the answer.

9

I emailed the Doxygen Forum …