Running and Verifying DL_POLY in Multi-node Mode

Use PuTTY to log in to the server as the root user.
Run the following command to decompress the TEST41 test case package:
```
tar zxf TEST41.tar.gz
```
Run the following command to go to the TEST41 test case directory:
```
cd TEST41/NHC
```
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.
On node 2, run the following command to configure environment variables:
```
vi /root/.bashrc
```

Press i to enter the insert mode, and add the following content to the end of the .bashrc file:

export PATH=/path/to/GNU/bin:/path/to/OPENMPI/bin:$PATH
export  LD_LIBRARY_PATH=/path/to/GNU/lib64:/path/to/OPENMPI/lib:$LD_LIBRARY_PATH
export PATH=/path/to/DL_POLY/dl_poly-RELEASE-1-10/execute:$PATH

Press Esc, type :wq!, and press Enter to save the changes and exit.
Run the following command to run the test case in multi-node mode:
```
mpirun --allow-run-as-root -np 256 -N 128 -x OMP_NUM_THREADS=1 --hostfile /path/to/HOSTFILE -mca btl ^openib DLPOLY.X
```
time elapsed since job start = XX seconds in the OUTPUT file indicates the performance. A smaller value of XX indicates better performance.

Figure 1 is an example of the output result.

Figure 1 An example result

Parent topic: Running and Verifying DL_POLY