Add example of using NNPOps with openmm-torch?

[jchodera]

@peastman: Can we add an example script of how to use NNPOps directly within openmm-torch?

cc @dominicrufa @jeherr @raimis

[peastman]

We need to finish making NNPOps conda installable first.

[jchodera]

@peastman: There's now a test conda package, but nobody is sure how to test it without an example of how to use it.

[raimis]

I'll make an example.

[raimis]

@jchodera I have created a draft of a tutorial (#62). You can see it better here: https://github.com/raimis/openmm-torch/blob/example/tutorials/openmm-torch-nnpops.ipynb

Or just

[raimis]

The tutorials is done (#62). @jchodera @peastman could you check it?

[raimis]

@jchodera could tweet about the new tutorial: https://github.com/openmm/openmm-torch/blob/master/tutorials/openmm-torch-nnpops.ipynb Also, this should be considered beta, but we need people trying it and find the remaining issues.

[raimis]

I keep this issue open as a reminder to update the tutorial, when following issue are fixed:

• An official NNPOps package is still not available: Conda-forge package of NNPOps NNPOps#26, Fix the tutorial #77
• Context.setVelocitiesToTemperature is broken (Setting velocities trigger an exception #61) and we need an OpenMM release with Fix GIL for OpenMM::Context::setVelocitiesToTemperature openmm#3424.

[jchodera]

This is waiting for the beta releases.