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Reference Guide
 
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Tree tutorials

Example code which illustrates how to use ROOT trees and ntuples.

Files

file  basic.C
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Read data from an ascii file and create a root file with an histogram and an ntuple.
 
file  basic2.C
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Create can ntuple reading data from an ascii file.
 
file  bill.C
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Benchmark comparing row-wise and column-wise storage performance
 
file  cernbuild.C
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Read data (CERN staff) from an ascii file and create a root file with a Tree.
 
file  cernstaff.C
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Playing with a Tree containing variables of type character
 
file  circular.C
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Example of a circular Tree
 
file  clonesA_Event.C
 Example to write & read a Tree built with a complex class inheritance tree.
 
file  copytree.C
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Copy a subset of a Tree to a new Tree
 
file  copytree2.C
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Copy a subset of a Tree to a new Tree, one branch in a separate file.
 
file  copytree3.C
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Example of Root macro to copy a subset of a Tree to a new Tree, selecting entries.
 
file  drawsparse.C
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Convert a THnSparse to a TTree using efficient iteration through the THnSparse and draw a THnSparse using TParallelCoord.
 
file  h1analysis.C
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Example of analysis class for the H1 data.
 
file  h1analysisProxy.C
 Example of analysis class for the H1 data using code generated by MakeProxy.
 
file  h1analysisTreeReader.C
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H1 analysis example expressed in terms of TTreeReader
 
file  h1chain.C
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Creates a TChain to be used by the h1analysis.C class the symbol H1 must point to a directory where the H1 data sets have been installed.
 
file  hsimpleProxy.C
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file  hsimpleProxyDriver.C
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This is the driver of the hsimpleProxy example It provides the infrastructure to run that code on an ntuple To be run from the tutorials directory
 
file  hsimpleReader.C
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TTreeReader simplest example.
 
file  htest.C
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Save histograms in Tree branches
 
file  hvector.C
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Write and read STL vectors in a tree.
 
file  jets.C
 Usage of a Tree using the JetEvent class.
 
file  ntuple1.C
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Simple tree analysis.
 
file  parallelcoord.C
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Script illustrating the use of the TParalleCoord class
 
file  parallelcoordtrans.C
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Use of transparency with ||-Coord.
 
file  printSizes.C
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This macro can be used to get aggregate information on the size take on disk or in memory by the various branches in a TTree.
 
file  run_h1analysis.C
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Macro driving the analysis can specify file name and type
 
file  spider.C
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TSpider example.
 
file  staff.C
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Create a plot of the data in cernstaff.root To create cernstaff.root, execute tutorial $ROOTSYS/tutorials/tree/cernbuild.C
 
file  tcl.C
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How to write a TClonesArray to a TTree
 
file  temperature.C
 This tutorial illustrates how to use the highlight mode with trees.
 
file  tree.C
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Display the Tree data structures
 
file  tree0.C
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Simple Event class example
 
file  tree1.C
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This example is a variant of hsimple.C but using a TTree instead of a TNtuple.
 
file  tree2.C
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This example illustrates how to make a Tree from variables or arrays in a C struct - without a dictionary, by creating the branches for builtin types (int, float, double) and arrays explicitly.
 
file  tree2a.C
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This example is the same as tree2.C, but uses a class instead of a C-struct.
 
file  tree3.C
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Example of a Tree where branches are variable length arrays A second Tree is created and filled in parallel.
 
file  tree4.C
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This example writes a tree with objects of the class Event.
 
file  treefriend.C
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Illustrates how to use Tree friends:
 
file  treegetval.C
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Illustrates how to retrieve TTree variables in arrays.