openmm | OpenMM is a toolkit for molecular simulation

I want to use a for loop to make the code shorter. In the following code I'm trying to create a chain of particles with same mass. Lets' say I want to create 50 particle. " system.addParticle(mass)" will add one particle. So basically to need 50 particles I have to repeat this 50 times. Is there any way to use for loop for that?

I need to import some functions from several files into a Jupyter Notebook, when I try to do this I get the module not found error despite all necessary files being present.

The original import code looks like this:

I am new to OpenMM and I would appreciate some guidance on the following matter:

Currently I am not interested in running molecular dynamics simulations, for starters I would just like to compute what are the forces or free energies between individual pairs of atoms using OpenMMs AMBER force field for example. Essentially I would like to end up with a heat map which represents forces between atom pairs something like this: Where numbers represent strength of the force or value of free energy.

I have trouble finding out how to access such lower level functionality of OpenMM where I could write a custom script that calculates only desired forces provided the 3D coordinates of atoms and their types. In their tutorials I have just found how to run fully fledged simulations by providing force field data and PDB files of molecular systems.

Preferably I would like to achieve this with python.

Any concrete example or guidance is much appreciated.

I've been recently dealing with come combined C++/CUDA. I am learning on this simple exmaple: