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Axel Naumann on

Hi!

There are still a few days until the next major version of ROOT will be available for download (June 30th). It's a good occasion to tell you want you might like about it! We have put more than thousand patches into ROOT since the last production release. Deciding what's relevant and interesting out of that is of course very much a matter of taste - so here is my personal list of favorite changes that showed up in ROOT during the last year:

PROOF Lite

This is the ideal way to speed up your analysis, by simply using all of the multiple cores that your machine offers! There is even a short manual for it. The basics are simple, though: you derive from TSelector (even the output of TTree::MakeClass() does), and you call 

  p = TProof::Open("")

That's it already!

The Fit Panel

Of course you derive the fit functions you use theoretically, and you determine the ideal initial parameters using the expertise that you gained over the many years in physics.

Right. For all the rest of us, there is the fit panel. It existed since years, but the new one is just SO much better. You can e.g. find it in the canvas under Tools :

fitpanel_0.png

This new fit panel allows you to fit anything, from histograms to trees, with (almost?) all possible options! I also really like the parameter input window, where one can define the bounds and the initial value, together with a live preview of what the fit function looks like given the initial parameters:

parameters_0.png

canvas_0.png

GL

Got used to your compiz desktop? What about some fancy GL in your ROOT canvas? This is what it looks like:

As you can see, you can pick bins (the status bad shows the coordinates and contents), you can move a projection through the histogram - and of course you see everything in an amazing quality, fast and beautiful.

What's the magic for that? You need to call 

   gStyle->SetCanvasPreferGL(kTRUE);

before you create your first canvas. And the canvas name must start with the letters gl . Yes, that's a funny way of selecting it and from what I heard it might get fixed soon :-) The last thing is to draw with one of the GL options, like "GLLEGO" as in this example.

So: enjoy the new version of ROOT! Next week I plan to post a few of ROOT's well hidden gems...

Cheers.

Comments

Submitted by Nefeli Iliana Kousi on Mon, 08/17/2009 - 11:07

Hi, I have compiz installed, and I tried to run this small code: gStyle->SetCanvasPreferGL(kTRUE); TCanvas gltest = new TCanvas("gltest","gltest"); gltest->cd(); TH2Dh = new TH2D("h","t",10,0,10,10,0,20); h->Fill(1,2); h->Fill(1,2); h->Fill(1,2); h->Fill(4,5); h->Fill(6,2); h->Fill(9,2); h->Fill(5,2); h->Fill(4,3); h->Draw("GLLEGO"); but I get this warning : Error in : RGL[.so | .sl | .dl | .a | .dll] does not exist in .:/home/poss/root/lib:/root/cint/cint/stl Do I need to install something new ? Thanks.

Submitted by Nefeli Iliana Kousi on Mon, 08/17/2009 - 21:38

Hi,

It seems your ROOT is compiled without OpenGL support. I assume you build your own ROOT - in this case you need to have gl-dev and glu-dev packages installed before running configure (on Debian the packages are libgl1-mesa-dev and libglu1-mesa-dev).

You don't need a full rebuild, just do (after installing the packages):

cd $ROOTSYS
./configure `cat config.status`
# make sure opengl is mentioned in the features paragraph towards the end
make

Good luck! Matevz

Submitted by Anonymous (not verified) on Sat, 07/04/2009 - 00:18

hi Axel, The GL example doesn't show up for me on a few different browsers (Firefox & Safari). It shows a quicktime logo, then it turns into a ~1 pixel wide 20 pixel tall line. I'd be interested to see the demo.

Submitted by Anonymous (not verified) on Tue, 07/07/2009 - 12:18

Humm, cross browser, cross platform standard video formats? Anyone?

I switched it to flash. The video quality is worse, but at least it should be supported everywhere.

Submitted by Anonymous (not verified) on Sat, 02/06/2010 - 22:25

This are great new features - I love GL. And thank you guys for improving the installation of ROOT. Now it's really easy! Go ahead and continue improving!

Submitted by Anonymous (not verified) on Sat, 02/27/2010 - 06:53

Hi Stephan,

glad to hear that our work arrives :-) The parts you mention have actually never been requested by the experiments using ROOT. For us it's always tricky to argue "users will appreciate it" when we are told "there has been no request for it!" So we really appreciate your feedback, be it praise or criticism or ideas for improvements!

Cheers, Axel