# Feel++ Data Files

Feel++ generates various files that are spread over various directories. For this tutorial, it would be beneficial to check the content of these files to familiarize yourself with Feel++.

## 1. Environment variables

The environment variable `FEELPP_REPOSITORY` define the root directory where the simulation results will be stored. By default they are set to `$HOME/feel`. If you want to change the root directory where the results are stored, define e.g. `FEELPP_REPOSITORY`.  in Feel++ docker images, such as `feel/feelpp`, it points to `/feel`. For running, ``docker run -it -v$HOME/feel:/feel feelpp/feelpp``

should get you this output

``feelpp@50381de2bd23:~$`` and here is the result of `echo$FEELPP_REPOSITORY` in the docker image

``````feelpp@50381de2bd23:~$echo$FEELPP_REPOSITORY
/feel``````

## 2. Results

Results of Feel++ simulations are stored in `\$FEELPP_REPOSITORY/feel/<your_app_name>/` or in a sub-directory. The name of the directory is `np_<num>` where `num` is the number of processors used by the numerical simulation.

### 2.1. Logfiles

Feel++ uses Google Glog to generate logfiles. They are stored in `np_<num>/logs`. By default, only the master MPI process produces a logfile. This can be changed using the option:

 Option Description Default value disable_log Disable logfile generation false log_level_process log level: 2 enable logging for all processes, 1 enable only for master 0 disable for all processes 1

A copy of the mesh and eventually the CAD can be found in `np_<num>`.