Issues Using OpenMM for acceleration

[Ari Munic]

Hi,

I've been trying to use OpenMM to accelerate my simulations. I did a custom build of OpenMM because the pre-existing binaries were for a diffrent version of Visual Studio. Whenever I try to run my simulation I get a report that says the load attempt failed, with this warning:

DuMM: Failed to load OpenMM plugin with message: The specified procedure could not be found.

Do I need to tell the program where I installed OpenMM? On the pdf it says all that is needed is to include this line:

Code: Select all

forceField.setUseOpenMMAcceleration(true);

which I did, but it doesn't work.

Thanks for your help.

[Michael Sherman]

Hi, Ari. This may be a version incompatibility. Are you also building Molmodel from source? I suspect that you must build Molmodel's OpenMM plugin against the currently installed version of OpenMM. The Molmodel binaries were built long ago and do not reflect the latest OpenMM. I would suggest:

• Build and install OpenMM from most recent source release
• Build and install Simbody from Simbody/branches/Simbody3.0
• Build and install Molmodel from Molmodel/trunk

Be sure to follow the build-from-source instructions that should be in /doc
directories. If you still have a problem at that point please repost with more information.

Regards,
Sherm

[Ari Munic]

I built Simtk from source, and then built MolModel from source using my installed version of OpenMM. However when I try to run a simulation using OpenMM acceleration I get the following message in the command prompt

LOAD ATTEMPT: '...SimTK\lib\plugins\OpenMMPlugin.dll' ... FAILED!
WARNING: DuMM: Failed to load OpenMM plugin with message: THe specified module could not be found.

I believe I have done everything correctly, is there a guide to configuring CMake to use OpenMM when building MolModel?

[Michael Sherman]

Hi, Ari.

A few thoughts:
- Make sure you checked the "MOLMODEL_USE_OpenMM" checkbox in the CMake user interface before the Configure/Generate step in CMake
- If so, when you go into Visual Studio you'll see a project in the Solution Explorer window called "Plugin - OpenMMPlugin".
- That should build successfully, and then you should build the INSTALL target. Be sure to notice into what folder you are installing Molmodel.
- The rather terse section 2.3.11 in the MolmodelUsersGuide has some instructions. You have to set the environment variable SimTK_INSTALL_DIR if you didn't use the default installation folder. Also there the setTraceOpenMM() method that is useful for debugging this kind of problem.
- Please post the trace output if you are still having trouble.

Regards,
Sherm