M. Novak 12 May 2022
====================


Download and extract into our `work` directory on the VM:
---------------------------------------------------------

Download `day4-start.tar.gz` from your VM (e.g. using `firefox`) then 
you and extract to our work directory that is `$HOME/geant4/work` as:
(go to our work directory; copy `day3-start.tar.gz` from ~/Downloads;
 then extract)

  localhost.localdomain:/app < 216 >cd $HOME/geant4/work/
  localhost.localdomain:/work < 217 >cp ~/Downloads/day4-start.tar.gz .
  localhost.localdomain:/work < 218 >tar -xzvf day4-start.tar.gz


Description:
------------

This is the starting point of our application at the beginning of day4. This 
state (where we stopped at the end of day3) contains only the implementation 
of the (mandatory) G4VUserDetectorConstruction, G4VUserActionInitialization, 
G4VUserPrimaryGeneratorAction interfaces (and a reference physics list). The 
(`yourMain.cc`) main of the application contains:

 - constrcution of the run manager

 - construction of the mandatory user initializations (i.e. objects form our
   implementations of the above mandatory ineterafces) and their registration
   in the run manager

 - then the run manager is initialized and a simple run is executed simulating 
   only 1 event with the default kinematical conditions of our primary generator
   (1 primary e- with 30 MeV initial kinetic energy)

 - `tracking verbose` is set to 1 in order to see the individual simulation 
   steps (we could not see anything related to the simulation at this point 
   otherwise)

I added comments to `yourMain.cc` that explains the details behind the individual
lines. This will be the starting point of our development at the beginning of day4. 


Configure, compile and run:
------------------------------

As before you can configure, build and execute the application on your VM (from
the `build` directory) as
 
  $ cmake ../ -DGeant4_DIR=$G4COMP
  $ make 
  $ ./yourMain

and you should see now even the output of the simulation, i.e. a step-by-step 
report (thanks to setting `tracking verbose 1`)