Some reshuffling and documentation

Revamp how things are compiled and move systemname to name of executable; make JUWELS the default and also add instructions for JUWELS

01-MSA-hello-world/Makefile

-EXECS=mpi_hello_world.out
+SYS:=none
+_SYS=$(addprefix .,$(SYS))
 MPICC=mpicc
 
+EXECS=mpi_hello_world$(_SYS).out
+
+.PHONY: all clean
 all: ${EXECS}
 
-mpi_hello_world.out: mpi_hello_world.c
-	${MPICC} -o mpi_hello_world.out mpi_hello_world.c
+mpi_hello_world$(_SYS).out: mpi_hello_world.c
+	${MPICC} -o $@ $<
 
 clean:
 	rm ${EXECS} *.out || true

01-MSA-hello-world/README.md

+# MSA Hello World
+
+In this simple example, the Slurm heterogeneous job functionality is used to launch a job between JUWELS Cluster and Booster.
+
+Execute the following on JUWELS Booster
+
+```bash
+bash compile.sh
+```
+
+Execute the following on JUWELS Cluster
+
+```bash
+bash compile.sh
+sbatch job_msa_juwels.sh
+```
+
+Monitor your job with `squeue --me`. When it ran through successfully, have a look at the output in `slurm-out.N`, with `N` being your job number.
\ No newline at end of file

01-MSA-hello-world/compile.sh

+if [[ "$SYSTEMNAME" == "juwelsbooster" ]]; then
+	echo "Building for $SYSTEMNAME"
+	ml GCC ParaStationMPI
+	make SYS=$SYSTEMNAME
+elif [[ "$SYSTEMNAME" == "juwels" ]]; then
+	echo "Building for $SYSTEMNAME"
+	ml GCC ParaStationMPI
+	make SYS=$SYSTEMNAME
+else
+	echo "The system $SYSTEMNAME is not supported!"
+	echo "Please load a capable MPI and compile the executables on each system with"
+	echo "make SYS=PARTIONNAME"
+fi
\ No newline at end of file

01-MSA-hello-world/compile_all.sh

-ml GCC ParaStationMPI
-make
-mv mpi_hello_world.out mpi_hello_world_cluster.out
-
-ml GCC ParaStationMPI
-make
-mv mpi_hello_world.out mpi_hello_world_booster.out

01-MSA-hello-world/job_msa_jureca.sh

@@ -11,4 +11,4 @@
 #SBATCH --ntasks-per-node=1
 #SBATCH --partition=dc-gpu-devel
 
-srun xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world_cluster.out : xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world_booster.out
+srun xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world.jureca.out : xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world.jureca.out

01-MSA-hello-world/job_msa_juwels.sh

@@ -11,4 +11,4 @@
 #SBATCH --ntasks-per-node=1
 #SBATCH --partition=develbooster
 
-srun xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world_cluster.out : xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world_booster.out
+srun xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world.juwels.out : xenv -P -L GCC -L ParaStationMPI ./mpi_hello_world.juwelsbooster.out

01-MSA-hello-world/mpi_hello_world.c

@@ -13,7 +13,7 @@ int main(int argc, char** argv) {
     int world_rank;
     MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
 
-    // Get the name of the processor
+    // Get the name of the processor, which is the hostname
     char processor_name[MPI_MAX_PROCESSOR_NAME];
     int name_len;
     MPI_Get_processor_name(processor_name, &name_len);