Re: QM/MM Parallel Computing With Orca

From: Marcelo C. R. Melo (
Date: Tue Sep 12 2017 - 09:45:08 CDT

Hello Collin,

In your "qmBaseDir" you should find temporary files related to the
(attempted) execution of ORCA. That could be a first place you could look
for more informative error messages. NAMD doesn't parse all possible errors
that ORCA could inform, it just knows that ORCA didn't end as expected.

You seem to have covered all your bases with the PATH and LD_LIBRARY_PATH
modifications, and your input looks fine, so without more information, and
since the serial simulations run ok, I could only assume that it has
something to Stampede's control over the nodes reserved for your job. In
ORCA's documentation for parallel jobs in a cluster, they make a point of
creating a "node file" to indicate which hosts are available for your job (
Could you check the output files in the scratch folder and your PBS job
submission file?


Marcelo Cardoso dos Reis Melo
PhD Candidate
Luthey-Schulten Group
University of Illinois at Urbana-Champaign
+1 (217) 244-5983
On 12 September 2017 at 09:12, Nisler, Collin R. <> wrote:
> Hello, I am attempting to run a QM/MM simulation with Orca on the
> Stampede2 supercomputer, and wanted to run the quantum simulation in
> parallel. I have installed Orca and openmpi as instructed on the Orca
> website, adding the bin and library directories of openmpi to my PATH and
> LD_LIBRARY_PATH. There is only one quantum region in my simulation. I
> submit the NAMD job and request 20 nodes, and in the NAMD conf file I use
> the following lines for the orca simulation:
> qmForces on
> qmParamPDB MmC23_ASI_QM.pdb
> qmColumn beta
> qmBondColumn occ
> QMElecEmbed on
> QMSwitching on
> qmBaseDir "/scratch/04267/cnisler/QMMM/MmP15C23/QMMM/mineq-01/QMmin01"
> qmConfigLine "! PM3 ENGRAD PAL8"
> qmConfigLine "%%output PrintLevel Mini Print\[ P_Mulliken \] 1
> Print\[P_AtCharges_M\] 1 end"
> qmMult 1 1
> qmCharge 1 -7
> qmSoftware orca
> qmExecPath /scratch/04267/cnisler/orca/orca_4_0_1_2_linux_x86-64_
> openmpi202/orca
> QMOutStride 1
> QMPositionOutStride 1
> So I am requesting Orca run in parallel with the "PAL8" keyword. However,
> I am continuing to get the rather vague error message "FATAL ERROR: Error
> running command for QM forces calculation." When I attempt to run this
> exact same simulation in serial, without the PAL8 keyword, it runs fine.
> Is there something more I need to do to run Orca in parallel with the
> QM/MM interface? Thanks in advance.
> Collin Nisler

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