Event Reweighting Tests

Authors: A. Lister, A. Mastbaum

These scripts check that reweighting of events in an analysis tree, via the TreeReader input source, produces exactly the same as running EventWeight directly on art ROOT files.

The TestModule module produces an example analysis tree with all the truth information required for reweighting. Feel free to adapt this code for writing analysis-specific output trees. Note that the branch names can be adjusted to your preferences (the mapping is specified when the analysis trees are read back in for reweighting), to minimize need to duplicate information and/or adapt existing analysis code.

N.B. This code assumes uboonecode v06_26_01_12 and gallery v1_03_13 -q e10:prof:nu. Adjust UBOONECODE_LIB in the Makefile for your environment.

Steps

1. Reweight some MC of your choice.

   For example:

   lar -c run_eventweight_microboone.fcl /pnfs/uboone/mc/uboone/detector-simulated/prodgenie_bnb_nu_uboone/sim/prod_v06_26_00/prodgenie_bnb_nu_uboone_0_20170228T015121_gen2_0aa93a49-868a-41dd-a795-e3ef4643f5b9.root
   mv <that output> mcc8_test.root
   

2. Turn that into an analysis tree with TestModule.

   Place TestModule into the uboonecode source, add it to the CMakeLists, and rebuild uboonecode. Then:

   lar -c run_test_module.fcl mcc8_test.root
   

3. Read the tree back in and re-run eventweight (same seeds).

   lar -c test_treereader.fcl testOutput.root
   

4. Check that all the weights match.

   make  # Build the test program
   ./check_weights mcc8_test.root treereader.root
   

   if any weights mismatch, it will print an error and abort immediately.

Converting art ROOT output to an Ntuple

The output of the tree reader input source (step 3) is an art ROOT file. A script to extract the event index, neutrino energy, and event weights and put them in a standalone ROOT ntuple is provided in test. Usage:

make
./arborist output.root input1.root [input2.root ...]

This will read all the events from the input file(s), and create one file called output.root with just the event ID, Enu, and std::map<std::string, std::vector<double> > with the weights.