Running and Verifying Elmer

Procedure

Use PuTTY to log in to the server as the root user.
Run the following command to create a hostfile file and add node information:
```
echo -e 'node1\nnode2\n…\nnodex' > /path/to/HOSTFILE
```
- In the preceding command, node1, node2, ..., and nodex indicate the host names of the nodes. You can run the hostname command to query the host names. \n indicates a newline character.
- This step is mandatory when multiple nodes are running and can be skipped when only one node is running.

Run the following commands to decompress the official package:

cd /path/to/ELMER/
tar -xvf ElmerTutorialsFiles_nonGUI.tar.gz

Run the following command to enter the test case:
```
cd tutorials_files/FlowResistance
```
- FlowResistance is one of the official test cases.
- For details about how to run other test cases, see the official manual.
Run the following command to generate a grid:
```
ElmerGrid 1 2 hole.grd
```

Run the following command to run the case:

time mpirun --allow-run-as-root -mca btl ^openib --hostfile /path/to/HOSTFILE -x PATH -x LD_LIBRARY_PATH -x ELMER_HOME -N 128 ElmerSolver

Run the following command to run the case in single-node mode:

time mpirun --allow-run-as-root -mca btl ^openib -np 128 ElmerSolver

After the command is run, the following information is displayed:

ElmerSolver: *** Elmer Solver: ALL DONE ***
ElmerSolver: The end
SOLVER TOTAL TIME(CPU,REAL):        10.23        2.86
ELMER SOLVER FINISHED AT: 2020/05/12 17:16:54

Parent topic: Elmer 8.4 Porting Guide (CentOS 7.6)