Difference: HiggsAnalysisAtATLASUsingRooStats (42 vs. 43)

using ROOT on the CERN LXPLUS network

Execute the following commands in order to set up ROOT version 5.32.00 on LXPLUS:

setting up RooStats

here

shell script: building ROOT with RooFit and RooStats

# This script builds the latest version of ROOT with RooFit and RooStats in Ubuntu.

option 3: Build the RooStats branch.

example code: defining a RooFit variable

RooPlot

example code: create a Gaussian PDF using RooStats and plot it using the RooPlot class

example code: telling a RooFit PDF what to normalise over

datasets

RooDataSet (unbinned data)

example code: generating toy Monte Carlo, storing it as unbinned data and then plotting it

example code: plotting unbinned data (a RooDataSet) using a specified binning

importing data from ROOT trees (how to populate RooDataSets from TTrees)

example code: import a ROOT histogram into a RooDataHist (a RooFit binned dataset)

fitting

fitting a PDF to unbinned data

example code: fit a Gaussian PDF to data

The RooFit workspace

example code: using the Workspace Factory to create a Gaussian PDF

What's in the RooFit workspace?

example code: What's in the workspace?

visual representations of the model/PDF contents

example code: examining PDFs and creating graphical representations of them

Model Inspector

The Model Inspector is a GUI for examining the model contained in the RooFit workspace. The function and it's parameters are as follows:

using the Model Inspector

accessing the RooFit workspace

example code: accessing the workspace

example code: accessing both data and PDF from a workspace stored in a file

// Open a file and import the workspace.

links for RooFit

example code: create a simple model using the RooFit Workspace Factory. Specify parts of the model using ModelConfig. Create a simple dataset. Complete a confidence interval test using the ProfileLikelihoodCalculator of RooStats

links for RooStats

example file: $ROOTSYS/tutorials/histfactory/example.xml

channel XML files

# This script is designed for use with the naming conventions described in the following page:

C++ approach to HistFactory

example (early in project development): creation of the Measurement and a Channel and, thence, creation of the channel samples, including signal and backgrounds

example HistFactory model construction using C++

A HistFactory model is to be created. It shall consist of a single channel that shall have only signal and background. Uncertainties on the luminosity, statistical uncertainties from Monte Carlo and separate systematics on signal and background shall be included.

details on HistFactory usage in C++

add a preprocessed function by giving the function a name, a functional expression and a string with a bracketed list of dependencies (e.g. "SigXsecOverSM[0,3]")

create a class representing a preprocess function and add it to a measurement directly using the constructor PreprocessFunction and a method of a measurement object

PreprocessFunction::PreprocessFunction(std::string Name, std::string Expression, std::string Dependents);
void AddPreprocessFunction(const std::string& function);

details on object channel

combining

Once each channel has been created, filled with data and samples and added to the overall measurement, the analysis can begin. The first step is to generate the RooFit model from the measurement object. This model is stored in a RooFit workspace object. There are two ways to do this. The first way is used by the program hist2workspace. It builds the workspace, fits it, creates output plots and saves the workspace and plots to files.