= prolog.wrf4g file =

The '''prolog.wrf4g''' configuration file let use specific tools locally on the remote computing resources. This file has to be in the same directory as '''[wiki:WRF4Gexperiment_wrf4g experiment.wrf4g] is located'''. In order to help you, we are going to show two examples:

* In the first one, we want to use your own WRF, WPS and NetCDF library compilation that are available on your remote computing resources. If we assume that all the jobs from an experiment have access to a local version, WRF4G will use binaries ('''ungrib.exe''' ,'''metgrid.exe''', '''real.exe''', '''wrf.exe''' and '''ncdump''') in order to simulate the experiments there. 
{{{
#!sh
[user@mycomputer~]$ cat prolog.wrf4g
export PATH=~/WPS:$PATH
export PATH=~/WRFV3/run:$PATH
export PATH=~/netCDF/bin:$PATH
}}}

* This second example presents a bash shell code which basically distinguishes between two resources using `$GW_HOSTNAME` variable. In this example, on mycomputer, you will use mpich2 with ethernet connection and on mycomputer2, you will use mvapich2 with infiniband connection.
{{{
#!sh
[user@mycomputer~]$ cat prolog.wrf4g
if [ $GW_HOSTNAME = mycomputer ]; then
    use WRFV3.3.1
    use netCDF4.1.3
    use mpich2
fi

if [ $GW_HOSTNAME = mycomputer2 ]; then
    use WRFV3.3.1
    use netCDF4.1.3
    use mvapich2
fi
}}}

How to know the value of all `$GW_HOSTNAME` variables?
{{{
#!sh
[user@mycomputer~]$ wrf4g_resources | awk {'print $11'}
HOSTNAME
mycomputer
mycomputer2
}}}