{{{
#!html
<h1>How to use the IPSL models and tools at LSCE</h1>
}}}
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[[PageOutline(1-2,Index du chapitre,,numbered)]]

The LSCE computing environment is detailed here: [https://w3.lsce.ipsl.fr/informatique/util/index.php]. You can only access this webpage via the LSCE network.

 * The interactivity

 The network includes a cluster for the interactive mode. This cluster is considered as a unique machine called '''asterix.lscelb.extra.cea.fr''' which can be shorten into '''asterix.lscelb'''.

The direct access to the cluster is only possible from the LSCE or from the CCRT machines. The cluster can be accessed via ssh and xdmcp protocols.

 * The computing cluster

   The LSCE has a small computing cluster. See its users' manual here: [https://w3.lsce.ipsl.fr/informatique/util/calcul/batch.php]. This cluster is considered as a unique machine called  ''obelix.lscelb.extra.cea.fr'' which can be shorten into '''obelix.lscelb'''.

## Modipsl and compiling ##
'''By default the compiling is meant to function in MPI parallel mode.''' The compiler is `ifort` (''Intel'' compiler). The '''lxiv8''' target in modipsl/util/AA_make.gdef is used on obelix. To this day, only ORCHIDEE is installed on obelix. [[BR]]


You must modify the makefile '''to run in sequential mode'''. To do so change the following lines in modipsl/util/AA_make.gdef
{{{
#-Q- lxiv8    F_C = mpif90 -c -cpp
#-Q- lxiv8    F_O = -DCPP_PARA -O3 $(F_D) $(F_P) -I$(MODDIR) -module $(MODDIR)
#-Q- lxiv8    F_L = mpif90
}}}

in 

{{{
#-Q- lxiv8    F_C = ifort -c -cpp
#-Q- lxiv8    F_O = -O  $(F_D) $(F_P) -I$(MODDIR) -module $(MODDIR)
#-Q- lxiv8    F_L = ifort
}}}
 
Then recreate the makefile with ./ins_make and compile as usual. 

## libIGCM and environment ##

libIGCM can be used on the LSCE computing cluster. 

The default shell at LSCE is `tcsh`, which syntax is different from the `ksh` syntax used by libIGCM. To configure your environment correctly in order to correctly run  libIGCM in `ksh`, the easiest is to copy the files `/home/users/igcmg/.bashrc` in your `$HOME`.

## Example of parallel MPI job ##
Here is an example of a simple job to run the orchidee_ol executable. All input files and the executable must be in the directory before running the executable. 
{{{
######################
## OBELIX      LSCE ##
######################
#PBS -N MyTest
#PBS -m a
#PBS -j oe
#PBS -q medium
#PBS -o Script_Output_SECHSTOM.000001
#PBS -S /bin/ksh
#PBS -v BATCH_NUM_PROC_TOT=4
#PBS -l nodes=1:ppn=4

cd $PBS_O_WORKDIR
mpirun -np ${BATCH_NUM_PROC_TOT} orchidee_ol
}}}


To submit it you need to use the command '''qsub''', and you can follow your simulation with the command '''qstat -u login'''