https://wiki.physik.uzh.ch/cms/ 2026-05-21T13:41:56+00:00 https://wiki.physik.uzh.ch/cms/ https://wiki.physik.uzh.ch/cms/_media/wiki:dokuwiki.svg text/html 2017-06-22T13:25:41+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:example_ttree?rev=1498137941&do=diff Below is an example on the use of TTree in pyROOT. Run in the command line with $ python trees.py and check output with $ root -l tree.root root [1] TBrowser a #! /usr/bin/env python import time start = time.time() from ROOT import gRandom, TFile, TTree, TH1D from array import array import numpy # alternative to array # Add branch to existing tree: # https://root.cern.ch/phpBB3/viewtopic.php?t=9661 # # Write directories into root files: # https://root.cern.ch/root/html/tutorial… text/html 2017-09-11T15:52:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:fit?rev=1505145169&do=diff [in progress] Fitting in ROOT Useful material on fitting in ROOT: * Fitting guide by ROOT. Useful materials on `RooFit`: * RooFit Manual (python) and RooFit Quick Start * Official RooFit tutorials in C++ (python). * TWiki on RooFit & RooStats. text/html 2017-09-05T08:37:45+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:pyroot_tfile?rev=1504600665&do=diff Getting started with ROOT -> Useful pyROOT snippets → Handling TFile files Handling TFile files Class references for: * TDirectory, * TFile. Adding a directory to a TFile Here is a basic example creating a file with on directory. If you want to create and save an object in this directory, e.g. a tree or histogram, use dir.cd() text/html 2017-09-05T08:35:53+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:pyroot_th1?rev=1504600553&do=diff Getting started with ROOT -> Useful pyROOT snippets → Handling TH1 histograms Handling TH1 histograms Here is the class reference for TH1. Importing ROOT classes To use TH1D in python, you can either only import a TH1D class: from ROOT import TH1D hist = TH1D("hist_name","hist_title",100,0,100) or all classes: from ROOT import * # loads all classes, and thus takes longer hist = TH1D("hist_name","hist_title",100,0,100) text/html 2018-02-28T13:03:23+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:pyroot_ttree?rev=1519823003&do=diff Getting started with ROOT -> Useful pyROOT snippets → Handling TTree trees Handling TTree trees Here is the class reference for TTree. Here is one file containing multiple examples. Creating a TTree with branches and writing it to a TFile Below is an example of creating and saving a tree with two branches (variables) each containing a randomly distributed variable for each event. text/html 2017-09-05T13:05:33+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:pyroot?rev=1504616733&do=diff Getting started with ROOT -> Useful pyROOT snippets Useful pyROOT snippets Here are some loose examples of ROOT in python that may be useful: * handling TTree trees, * handling TH1 histograms, * handling TFile files and TDirectory directories, * RooFit and RooStats tutorials, RooFit manual. * more by the LHCb group. (More snippets to follow.) text/html 2017-09-07T16:46:32+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.physik.uzh.ch/cms/root:root?rev=1504802792&do=diff Getting started with ROOT ROOT is a framework based on C++ that is specialized in processing data in High Energy Physics. Some of its central classes are * TTree to store data; typically variables are stored in branches for each entry/event (e.g. a proton-proton collision),