Introduction

This repository is best considered in two parts. The first is a CMSSW package (UserCode/ICHiggsTauTau), which follows the standard conventions:

• Physics object classes defined and implemented in the interface and src directories
• CMSSW modules defined and implemented in the plugins directory that covert CMSSW objects to these formats
• Configuration fragments for cmsRun jobs in the python directory
• Complete configurations for cmsRun jobs in the test directory
• Compiled using the scram tool, which will produce ROOT dictionaries for the object classes following the specification in the src/classes.h and src/classes_def.xml

The second part is an offline analysis framework, organised into a series of packages within the Analysis directory. This provides:

• A modular build system implemented with make
• A simple framework for analysing events, in which the work is done by module classes, in a similar fashion to the CMSSW framework
• The same physics object classes from above are provided in the Objects package, with ROOT dictionaries built using the standard rootcint method and steered by the Objects/interface/LinkDef.h file.

Documentation can be produced by running docs/make_docs.sh from within the ICHiggsTauTau directory. An up-to-date copy can always be found here: http://ajgilbert.github.io/ICHiggsTauTau/index.html

The instructions for setting a CMSSW area with the ICHiggsTauTau package are reproduced below.

Setting up CMSSW

The following steps set up a new area, but note that only certain CMSSW releases are supported. All object classes and CMSSW modules compile should successfully with scram in each of the supported CMSSW release series:

	CMSSW_5_3_X
	CMSSW_7_0_X, CMSSW_7_1_X, CMSSW_7_2_X, CMSSW_7_3_X

The official CMSSW repository is hosted here: https://github.com/cms-sw/cmssw. If you do not already have a GitHub account, please read through the instructions at http://cms-sw.github.io/cmssw/faq.html, in particular ensure you have configured git with your personal information:

	git config --global user.name [First Name] [Last Name]
	git config --global user.email [Email Address]
	git config --global user.github [GitHub account name]
	#If you are running at IC you also need to do: git config --global http.sslVerify false
	#This extra line is not needed at CERN. Anywhere else if you see a fatal error message relating to SSL certificate problems it may be required

Before working with CMSSW in git, you will need to create a copy (or fork) of the official CMSSW repository in your own account at https://github.com/cms-sw/cmssw/fork. You will be able to store your own CMSSW branches and developments in this forked repository.

Create a new CMSSW area:

	export SCRAM_ARCH=slc6_amd64_gcc491
	# Or older, e.g. slc5_amd64_gcc472, slc6_amd64_gcc481
	scramv1 project CMSSW CMSSW_X_Y_Z
	cd CMSSW_X_Y_Z/src/
	cmsenv

Initialise this area for git by adding a single package:

	git cms-addpkg FWCore/Version
	# If you are not running on a machine based at CERN, this script will ask if you want to create a new reference repository.
	# You should answer yes to this, and the script will copy the entire cmssw repository to your home folder,
	# which will make setting up subsequent release areas a lot faster.

This command will have created two remote repositories, official-cmssw and my-cmssw. It will also have created and switched to a new branch, from-CMSSW_X_Y_Z. An additional remote should be added which provides the pre-configured branches:

	git remote add ic-cmssw [email protected]:ajgilbert/cmssw.git
	# fetch from the ic-cmssw remote repository and merge the from-CMSSW_X_Y_Z into your own local branch.
	git pull ic-cmssw from-CMSSW_X_Y_Z
	# Check which branch you actually need to merge in here. Descriptive names are useful, e.g. "higgstautau_from-CMSSW_5_3_7"

	# At this point, if you run 'ls' you will not see any new packages in the release area.
	# This is because the repository operates in sparse-checkout mode, hiding folders unless they are
	# explicitly made visible.  This is important, as we don't want to have to compile every single package.
	# To make the packages visible that have been modified from the release tag, run these commands:

	git cms-sparse-checkout CMSSW_X_Y_Z HEAD
	git read-tree -mu HEAD

	# You may optionally make other packages visible that depend on those which have been modified, so that
	# they will be recompiled.
	git-cms-checkdeps -a
	# In principle this should have also been done when using CVS, but is still not essential.

Next, add the IC analysis code package:

	git clone [email protected]:ajgilbert/ICHiggsTauTau.git UserCode/ICHiggsTauTau
	./UserCode/ICHiggsTauTau/init_X_Y_Z.sh  # (if exisits) This script performs a few final tasks in the new cmssw area

At this point everything is ready, and the working area can be compiled in the normal way with scram. New developments that are relevant for everyone can be committed to a branch and pushed to central IC repository (ic-cmssw). If you wish to test some new changes, or just share with specific people, it will be safer to work from a new branch, either based on the CMSSW release tag, or some commit on the from-CMSSW_X_Y_Z branch, e.g.

	git checkout -b my-analysis-from-CMSSW_X_Y_Z CMSSW_X_Y_Z # from the release tag
	git checkout -b my-analysis-from-CMSSW_X_Y_Z from-CMSSW_X_Y_Z # from the pre-configured branch
	... do some development ...
	git push my-cmssw my-new-branch