= WRF configuration =

To use WRF model in WRF4G2.0, you have to configure `app` variable in the [wiki:WRF4G2.0/Experiment experiment.wrf4g] file. By default, WRF4G2.0 provides a bundle with all you need to simulate an WRF experiment, configure as follows :

{{{
app = wrf_all_in_one | bundle | /home/user/wrf4g/repository/apps/WRF/WRFbin-3.4.1_r2265_gfortran.tar.gz
}}}

This bundle is able to be used for any x86_64 Linux system, and contains binaries, libraries and configuration files for WRF-3.4.1 build against gfortran-4.4.7, openmpi-1.4.3 and netcdf-4.1.3, which are include in the bundle too. 

But, if you want to use your own WRF installed on your machine or on a cluster, you have to update the `app` variable. There are several ways to configure this variable depending on your WRF configuration system. In order to clarify that, we are going to write some examples:     

* Using [http://modules.sourceforge.net/ module] command:
{{{
app =   wps | command | module load wps/4.5.1
        wrf | command | module load wrf/4.5.1
}}}
 
[[NoteBox(note, We assume that each command is configuring other softwares such as openmpi\, netcdf and so on.)]]

* Using `PATH` and `LD_LIBRARY_PATH` shell variables:
{{{
app = netcdf_bin | command | export PATH=/home/user/netcdf-4.1.3/bin/:$PATH
      netcdf_lib | command | export LD_LIBRARY_PATH=/home/user/netcdf-4.1.3/lib/:$LD_LIBRARY_PATH
      wrf_bin    | command | export PATH=/home/user/WRF4.5.1/:$PATH

}}}
* If WRF is already configured on your system, you do not have use `app` variable.