GitLab

Changes to support CHARMM polarizable force field

Fix bug in __ne__ implementation from #2616

Apparently it is the slightly more correct way of doing thigns, as explained in
https://stackoverflow.com/a/30676267/538973

* Use list-comprehension in Python code

A minor change, but slighly easier to understand the initialization of
`parent_exclude_list` in my opinion.

* Implement __ne__ in Python classes that has __eq__

In Python 3, `__ne__` is automatically implemented as `not __eq__`.

However, in Python 2 it seems to be implemented as `not is` (so based on object
identity).

Based on setup.py [0] which says that "OpenMM requires Python 2.7 or better", it
should be useful to have better support for Python 2 :)

This was already done in 4 of the 12 classes that implements `__eq__`

```
>>> class WildCard(object):
...     def __eq__(self, other): return True

>>> w = WildCard()

>>> w == 42
True

>>> w != 42
True

>>> w != w
False
```

[0]: https://github.com/openmm/openmm/blob/5cef29ce8d4e17b6d0f9fd8a3c6cc1669ca0ba2b/wrappers/python/setup.py#L237

* Use umambiguous floor division for index calculations in Python

This makes the code work as intended if run as Python 3

```
$ python2 -c 'print(3/2, 3//2)'
(1, 1)
$ python3 -c 'print(3/2, 3//2)'
1.5 1
```

* Use `with` for file handling in Python

* Use `is None` instead of `== None` in Python

This is recommended in PEP8:

> Comparisons to singletons like None should always be done with is or is not, never the equality operators.
> - https://www.python.org/dev/peps/pep-0008/#programming-recommendations

Update Azure VM to newer version

* Remove unused variable from CpuCustomGBForce::calculateIxn

* Remove unused variable from CpuCalcCustomManyParticleForceKernel::initialize

* Remove unused variable from CudaCalcCustomCVForceKernel::initialize

* Remove unused variable from ReferenceCalcCustomManyParticleForceKernel::initialize

* Remove unused variables from ReferenceObc::computeBornEnergyForces

* Remove unused variable from AmoebaTorsionTorsionForceProxy::serialize

Accept more variants of labels in CHARMM files

bug fix for handling constraints and rigidWater in CharmmPsfFile

setVelocitiesToTemperature() applies offset for leapfrog integrators

Made a test case more reliable

Modify temperature initialization mechanism

Allow ForceField to add custom prefix to templates when loading XML files

Fix error loading CPU PME on Mac

Prefer runtime compiler over nvcc

Convert Nose Hoover integrator to Common plaform

Switched dlopen flag from RTLD_GLOBAL to RTLD_LOCAL