Fast mtt 19 02 2019 wrapper

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "wrapper/pybind11"]
+	path = wrapper/pybind11
+	url = https://github.com/pybind/pybind11.git

README.md

@@ -12,7 +12,7 @@ In order to install the code, execute:
 cmsrel CMSSW_9_4_4
 cd CMSSW_9_4_4/src
 cmsenv
-git clone https://github.com/SVfit/ClassicSVfit TauAnalysis/ClassicSVfit -b fastMTT_19_02_2019
+git clone --recursive https://github.com/SVfit/ClassicSVfit TauAnalysis/ClassicSVfit -b  fastMTT_19_02_2019
 git clone https://github.com/SVfit/SVfitTF TauAnalysis/SVfitTF
 cd $CMSSW_BASE/src
 scram b -j 4
@@ -51,6 +51,22 @@ If everything goes right, this should produce a root file.
 
 ### `ClassicSVFit/FastMTT` in `Python` from C++ needs a *Wrapper* 🎁 
 
+
+#### Installation of pybind11:
+
+Tested with pybind11 v2.13.0 dev1.
+
+Git clone pybind11 module in `/wrapper` if `--recursive` is not used, and then compile: 
+
+```bash
+git submodule add [email protected]:pybind/pybind11.git
+mkdir build
+cd build
+cmake ..
+make check -j 4
+```
+
+
 TThis wrapper has been developed with the purpose of using it with the [ColumnFlow](https://columnflow.readthedocs.io/en/latest/) columnar Python-based framework. In order to use `ClassicSVFit` in Python, the [pybind11](https://pybind11.readthedocs.io/en/stable/basics.html) wrapper has been used. The wrapper for the different classes can be found here : [pybind_wrapper.cpp](https://github.com/oponcet/ClassicSVfit/blob/fastMTT_19_02_2019/wrapper/pybind_wrapper.cpp).
 
 The cloned `ClassicSVFit` already contains the `pybind11` and the `wrapper` itself. A few more things to modify [hard-coded, please be patient !!!]
@@ -70,3 +86,32 @@ It should produce a `.so` file which can be used as a module in Python. For exam
 ```py
 from modules.extern.TauAnalysis.ClassicSVfit.wrapper.pybind_wrapper import *
 ```
+
+
+### Wrapper example :
+
+You can run the example of fasttMTT, but before you need to export the right library like 
+
+```bash
+LD_LIBRARY_PATH=/usr/local/lib
+CPPYY_BACKEND_LIBRARY=/cvmfs/sft.cern.ch/lcg/app/releases/ROOT/6.30.04/x86_64-centosstream9-gcc113-opt/lib/libcppyy_backend3_9.so
+source /cvmfs/sft.cern.ch/lcg/app/releases/ROOT/6.30.04/x86_64-centosstream9-gcc113-opt/bin/thisroot.sh 
+export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:yourpath/TauAnalysis/ClassicSVfit/lib
+export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/cvmfs/sft.cern.ch/lcg/app/releases/ROOT/6.30.04/x86_64-centosstream9-gcc113-opt/lib/
+export LIBRARY_PATH=$LIBRARY_PATH:$PWD/TauAnalysis/ClassicSVfit/lib
+```
+
+The try running the python example `[`svfit_wrapper_example.py`](wrapper/svfit_wrapper_example.py)`:
+
+```bash
+python3 svfit_wrapper_example.py
+```
+
+>output should looks like: 
+```bash
+tau1P4mtt : Name: TLorentzVector Title: A four vector with (-,-,-,+) metric
+tau1P4mtt : Name: TLorentzVector Title: A four vector with (-,-,-,+) metric
+ditauMass : 105.58224459511314
+```
+
+