GitLab

* Initial implementation of C++ API

* Add kernel interface and information for API generation

* API updates for updating electrode parameters

* Add serialization proxy for ConstantPotentialForce

* Update file headers

* Add CG error tolerance and fix units on getCharges() return value

* Initial implementation of matrix solver

* Fixes and conjugate gradient solver

* Try to fix Linux and Windows builds

* Make sure charge constraint target is on total charge

* Restore handling of exceptions like NonbondedForce since they won't involve electrode atoms

* Ameliorate numerical instability in constrained conjugate gradient

* Fix uninitialized pointers, memory leak, and style

* Set CG tolerance units in Python API

* Test ConstantPotentialForce serialization

* Read/write ExceptionsUsePeriodicBoundaryConditions as bool

* Improve constrained conjugate gradient robustness to roundoff error accumulation

* Recompute matrix if electrode atoms move due to setPositions()

* Tolerance is now in gradient (potential) units again

* Add neutralizing background correction

* Add Python API tests

* Fixes for CG and nonbonded exceptions

* Add initial tests checking against existing NonbondedForce behavior

* Expand test suite and fix some implementation issues

* Add additional tests using larger reference system

* Add Gaussian test

* Finish test against reference computation

* CPU platform implementation

* Fixes for compilation on some platforms

* Fixes for constant potential with AVX/AVX2

* Test linking CPU PME library to constant potential test directly

* Older SWIG versions don't support Python set to C++ set conversion

* Add user guide entry

* Increase speed of reference test

* Conditional building constant potential CPU test is unreliable

* Debugging

* Miscellaneous fixes and improvements for CI

* Cache charges so solver will not run if system and coordinates have not changed

* Preconditioner flag, stability, and automatic detection improvements

* Add GPU platform-specific constant potential kernel classes

* PME and device-host I/O changes to support constant potential

* Initial common constant potential implementation

* Constant potential fixes:

* Fix preconditioner PME position/charge save/restore logic

* Fix reduction synchronization in constant potential solver kernels

* Add double-float accumulation for conjugate gradient solver when
  double unsupported by hardware

* Improve conditioning of a test system, and make sure particles are in or
out of cutoff for consistency and ease of comparing between platforms

* Reorder guess charges for CG when atom reordering changes positions

* Remove PME queue for now

* Trying to debug optimized direct space derivative kernel

* Remove extraneous debugging lines

* Style updates; just make CPU preconditioner double precision

* Debugging updated optimized direct derivatives kernel for all but OpenCL CPU

* OpenCL CPU implementation of direct space derivatives, and cleanup

* Try to make test even shorter to not time out on CI

* Temporary - Debugging

* Debugging

* Debugging

* Debugging

* Debugging

* Remove debugging code and fix reduction synchronization

* Fix other reductions

* Debugging - are tests hanging or just slow on CI?

* Debugging

* Debugging

* Fix macro for case when double precision is available on hardware

* Remove changes for debugging again

* Try to improve matrix solver cache locality by uploading transpose

* Fixes for atom ordering and periodic images

* Can't rely on reorder listener for cell offset updates

* Test reducing number of contexts and timing for CI

* Debugging

* Remove timing code and revert debugging changes

* Matrix solver and plasma term optimizations

* Reduce CG solver kernel calls and downloads

* Don't read back convergence flag from global memory

* Update PME due to refactoring in master branch

* Faster matrix solver (1st step)

* Faster matrix solver for CUDA

* Faster matrix solver compatibility with non-CUDA platforms

* Matrix solver fixes

* Use warp shuffle reductions when possible

* Attempt to work around intermittent compiler crash in Intel CPU OpenCL

* Optimize CG solver kernel 1

* Rework CG solver so some kernels can use more than 1 block

* Don't run out of shared memory

* Asynchronously download convergence flag while clearing buffers

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Co-authored-by: Evan Pretti <pretti@sh03-17n15.int>