= library !RootTuple =

Starting with release 2018, the code is able to produce particle vector output as a ROOT file.
Here we rely on the library [https://roottuple.hepforge.org/ RootTuple], which is a rudimentary Fortran interface to some existing [https://root.cern.ch/ ROOT] installation.

Unfortunately, the default installation process of '!RootTuple' produces only a 'shared' library (*.so) , which is not usable with GiBUU; here we need a 'static' library (*.a). Therefore some rework is needed and the total installation process reads:

1) Download the source from https://roottuple.hepforge.org/

2) Modify the file `RootTuple-master/src/CMakeLists.txt` by changing one line
{{{
add_library (RootTuple SHARED ${RootTuple_SOURCES})
}}}
to
{{{
add_library (RootTuple STATIC ${RootTuple_SOURCES})
}}}

3) follow the usual given build procedure of '!RootTuple'
  ...here internals to your ROOT installation may enter...

4) make the library accessible for GiBUU, e.g.:
{{{
cp RootTuple-master/build/src/libRootTuple.a <your/path/to/GiBUU>/objects/LIB/lib/libRootTuple.100.a
}}}
  (Here the '...100...' indicates the version number, which is fixed to be 1.0.0; please do not change!)

After this, a new rebuild of GiBUU should detect the library and automatically enable 'ROOT' as a possible output format.