Update running_openmpi.md

docs.it4i/software/mpi/running_openmpi.md

@@ -7,7 +7,7 @@ The OpenMPI programs may be executed only via the PBS Workload manager, by enter
 ### Basic Usage
 
 !!! note
-    Use the mpiexec to run the OpenMPI code.
+    Use the `mpiexec` to run the OpenMPI code.
 
 Example (for Anselm):
 
@@ -26,10 +26,9 @@ $ mpiexec -pernode ./helloworld_mpi.x
 ```
 
 !!! note
-    In this example, the directive **-pernode** is used to run only **one task per node**, which is normally an unwanted behavior (unless you want to run hybrid code with just one MPI and 16 OpenMPI tasks per node). In normal MPI programs, **omit the -pernode directive** to run up to 16 MPI tasks per each node.
+    In this example, the directive `-pernode` is used to run only **one task per node**, which is normally an unwanted behavior (unless you want to run hybrid code with just one MPI and 16 OpenMPI tasks per node). In normal MPI programs, **omit the `-pernode` directive** to run up to 16 MPI tasks per each node.
 
-In this example, we allocate 4 nodes via the express queue interactively. We set up the OpenMPI environment and interactively run the helloworld_mpi.x program. Note that the executable helloworld_mpi.x must be available within the
-same path on all nodes. This is automatically fulfilled on the /home and /scratch filesystem.
+In this example, we allocate 4 nodes via the express queue interactively. We set up the OpenMPI environment and interactively run the helloworld_mpi.x program. Note that the executable helloworld_mpi.x must be available within the same path on all nodes. This is automatically fulfilled on the /home and /scratch filesystem.
 
 You need to preload the executable, if running on the local scratch /lscratch filesystem:
 
@@ -43,16 +42,16 @@ $ mpiexec -pernode --preload-binary ./helloworld_mpi.x
     Hello world! from rank 3 of 4 on host cn110
 ```
 
-In this example, we assume the executable helloworld_mpi.x is present on compute node cn17 on local scratch. We call the mpiexec with the **--preload-binary** argument (valid for OpenMPI). The mpiexec will copy the executable from cn17 to the /lscratch/15210.srv11 directory on cn108, cn109, and cn110 and execute the program.
+In this example, we assume the executable helloworld_mpi.x is present on compute node cn17 on local scratch. We call the `mpiexec` with the `--preload-binary` argument (valid for OpenMPI). The `mpiexec` will copy the executable from cn17 to the /lscratch/15210.srv11 directory on cn108, cn109, and cn110 and execute the program.
 
 !!! note
     MPI process mapping may be controlled by PBS parameters.
 
-The mpiprocs and ompthreads parameters allow for selection of number of running MPI processes per node as well as number of OpenMP threads per MPI process.
+The `mpiprocs` and `ompthreads` parameters allow for selection of number of running MPI processes per node as well as number of OpenMP threads per MPI process.
 
 ### One MPI Process Per Node
 
-Follow this example to run one MPI process per node, 16 threads per process (**on Salomon, try 24 threads in following examples**).
+Follow this example to run one MPI process per node, 16 threads per process (**on Salomon, try 24 threads in following examples**):
 
 ```console
 $ qsub -q qexp -l select=4:ncpus=16:mpiprocs=1:ompthreads=16 -I
@@ -60,7 +59,7 @@ $ ml OpenMPI
 $ mpiexec --bind-to-none ./helloworld_mpi.x
 ```
 
-In this example, we demonstrate tthe recommended way to run an MPI application, using 1 MPI processes per node and 16 threads per socket, on 4 nodes.
+In this example, we demonstrate the recommended way to run an MPI application, using 1 MPI processes per node and 16 threads per socket, on 4 nodes.
 
 ### Two MPI Processes Per Node
 
@@ -112,9 +111,9 @@ $ export OMP_PLACES=cores
 
 ## OpenMPI Process Mapping and Binding
 
-The mpiexec allows for precise selection of how the MPI processes will be mapped to the computational nodes and how these processes will bind to particular processor sockets and cores.
+`mpiexec` allows for precise selection of how the MPI processes will be mapped to the computational nodes and how these processes will bind to particular processor sockets and cores.
 
-MPI process mapping may be specified by a hostfile or rankfile input to the mpiexec program. Altough all implementations of MPI provide means for process mapping and binding, the following examples are valid for the OpenMPI only.
+MPI process mapping may be specified by a hostfile or rankfile input to the `mpiexec` program. Altough all implementations of MPI provide means for process mapping and binding, the following examples are valid for the OpenMPI only.
 
 ### Hostfile
 
@@ -179,9 +178,9 @@ $ mpiexec -n 5 -rf rankfile --report-bindings ./helloworld_mpi.x
     Hello world! from rank 2 of 5 on host cn108
 ```
 
-In this example, we run 5 MPI processes (5 ranks) on four nodes. The rankfile defines how the processes will be mapped on the nodes, sockets and cores. The **--report-bindings** option was used to print out the actual process location and bindings. Note that ranks 1 and 4 run on the same node and their core binding overlaps.
+In this example, we run 5 MPI processes (5 ranks) on four nodes. The rankfile defines how the processes will be mapped on the nodes, sockets and cores. The `--report-bindings` option was used to print out the actual process location and bindings. Note that ranks 1 and 4 run on the same node and their core binding overlaps.
 
-It is the user's responsibility to provide the correct number of ranks, sockets, and cores.
+The user must provide the correct number of ranks, sockets, and cores.
 
 ### Bindings Verification
 

[Jan Siwiec]

relates to #70