[gmx-users] Running gromacs on Rocks cluster

[Lang Kong]

Dear all,I am running into a problem running gromacs in parallel mode on a rocks cluster using CentOS.  When I specify N processors on a single node, it works fine, but when I specify N processors that would require it to span multiple nodes, it runs the same simulation on each node independently rather than having the nodes work together on a single simulation.  
For installation, I basically followed the procedure here:Compile and run GROMACS 4.5.3 in the Intel® Cluster Ready Reference Recipe S5520UR-ICR1.1-ROCKS5.3-CENTOS5.4-C2 v1.0 | Intel® Developer Zone

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| Compile and run GROMACS 4.5.3 in the Intel® Cluster Ready Reference Recipe S5520UR-ICR1.1-...In this article I will show you how to compile GROMACS 4.5.3 using the latest Open Source Intel Cluster Ready Reference Design S5520UR-ICR1.1-ROCKS5.3-CENTOS5.4-C2 v1.0 |
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| View on software.intel.com | Preview by Yahoo |
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except that I am using gromacs 5.0, open mpi, and CentOS 7
Maybe I need to specify each node (hostname) somehow?
I have a feeling that I'm missing something really basic so thanks in advance for whatever help you can offer.
LK