My general purpose root ntuple weight branch creation code

This is the final script called to create weights on on a tree. At the moment it is hard coded to look for a tree called 'mt_Selected'.

This script will create a final weight with all the weights defined on your sample multiplied together, final weights with individual up/down uncertainties defined on your weights applied, as well as individual weight branches to examine the shapes of individual weights, and their up/down uncertainties.

• --ConfigFiles: Required, takes any number of arugments, which are just the paths to configuration files to run the tool
• --Remove: provides a tool for the removal of branches in case an error has been made

Where the final ReweightScheme configuration class is defined.

Convenient spot for writing your own weighting scheme configurations

Where all the weights that can be added to samples are defined.

Contains root files with scale factors and other necessary things in them.

• Open a python file, at the top import the weight definition from Configurations.Weights.WeightDefinition import Weight as Weight (and if you need a file in Data, the local data path, from Configurations.Weights import localWeightDataPath)
• Define a function that takes two arguments, the Weight itself (self) and the tree with the current event loaded (can be called whatever, but I find it convenient to label it theTree). The end result of this function must be to set self.value[0] to the proper value for the weight.
• If this weight has up/down uncertainties, you will need to define additional functions. These functions behave similarly to the nominal but take an additional argument (that I call uncert). This is a little bit clunky, but at the end of the day, what this function must do is similar to the abov but instead it will fill self.uncertaintyVariationArrays[uncert][0]
• Now to make the weight you declare an instance of the weight class: MyWeight = Weight()
• Set it's name with Weight.name = 'MyWeight' (This is how it will show up in the tree)
• Oftentimes, if you have something you would like to for the object to use in the function, a scale factor tool or the like it is useful to declare it as an instance variable here as well. Strictly optional.
• You need to set the configuration's CalculateWeight variable to your function like so: MyWeight.CalculateWeight = MyFunction (no parantheses)
• (optional) if your weight comes with up/down uncertainties, set the MyWeight.hasUpDownUncertainties variable to True
• (optional) if your weight comes with up/down uncertainties, set the various names of all the related weights in the uncertaintyVariationList list with MyWeight.uncertaintyVariationList = ["Weight_error1_UP","Weight_error1_DOWN","Weight_error2_UP",...] (the "UP","DOWN" is not strictly necessary, but recommended for clarity).
• (optional) if your weight comes with up/down uncertainties, a little extra set-up of the histograms is necessary, so now call: MyWeight.InitUncertaintyVariations()
• (optional) finally, if your weight comes with up/down uncertainties, create a dictionary (MyWeight.uncertaintyVariationFunctions) with all the names you provided before as keys, and with the functions to calculate the weight up/down as the values like so: MyWeight.uncertaintyVariationFunctions = {"MyWeight_error1_UP":myFunction_Error1_up,...}

• Open a python file. You will need to import the configuration definition: Configurations.ConfigDefinition import ReweightConfiguration
• Also, import all of the instances of weights that you will need to be applied to your final product.
• Create an instance of the reweight configuration: MyConfiguration = ReweightConfiguration()
• Set it's name (No defined behavior, but could be used by behavior you write) MyConfiguration.name = theName
• Set the path to the input file to get reweighted: MyConfiguration.inputFile = "/path/to/file.root"
• (optional) some weights (like ones I have created for corss section and pileup) will need years and sample names given to them at the time of configuration. This is a good spot to do that. See some of my written configurations for examples of what I mean
• The only other required thing is that all defined weights are put in the configuration's listOfWeights list like so: MyConfiguration.listOfWeights = [MyWeight, MyOtherWeight,MyThidWeight,...]

Contains a simple object used to load python modules from absolute directory paths.

Typically, once you have configurations defined, running should be as simple as: python FinalReweight.py --ConfigFiles <Path to configuration files. Supports wildcards.>

I would love to see use of this tool expand beyond just me, so if you have ideas or improvements, please let me know or open a PR.