sPuReMD: refactoring to better align with PuReMD code. PuReMD: backport sPuReMD changes from validation efforts against Fortran ReaxFF code.

sPuReMD: fix issue with hbonds list indices not being reset correctly. Small algebraic rearrangements of valence angle calculations to match Fortran ReaxFF code (no numeric changes). Fix issue with rvec_isZero being incorrect. Fix issue with debugging arrays for TEST_FORCES not having indicies initialized. Other clean-up work.

sPuReMD: re-enable SMALL_BOX_SUPPORT. Fix issue with far nbrs list being incorrectly generated for small boxes (missing nbr ID). Fix issue with ACKS2 matrix being incorrect for small boxes due to multiple non-zeros being added for each perioidic image of an atom (accumulate instead). Add missing ACKS2-specific energy and forces term. Clean-up far nbr list estimation and generation code for small boxes. Do not add far list struct entries unless the atom is below the specified cutoff.

sPuReMD: refactoring to align code with PuReMD. Disable SMALL_BOX_SUPPORT. Refactor to remove union-based polymorphic behavior for reax_list. Other general code clean-ups.

sPuReMD: backport changes for reax_list, struct declaration/definition separation, interaction_function.

sPuReMD: make CoM logic consistent with PuReMD. Other build system updates for debugging and newer versions of MPICH.

sPuReMD: add checks on string and file handling. Rewrite PDB writing to be line-by-line. Other refactoring.

sPuReMD: remove debug prints. Default to no good initial guess for out of range values for spline extrapolation.

sPuReMD: move NaN checks on system energy to after logging. This allows better diagnostics for, e.g., the potential logging.

sPuReMD: separate total energy computation and fix Python driver bug with structure definition for ctypes. Allow disabling file logging during simulation.

sPuReMD: fix GMRES bug introduced from previous refactoring. Explicitly link OpenMP for library. Refactoring to remove global variables. Remove unnecessary OpenMP barriers after single regions.

sPuReMD: split into library and driver for, e.g., optimization integration. Fix bug with interaction lists being allocated for hydrogen bonds when no hydorgen atoms present. Fix minimum allocation size of 3-body lists (uncovered with small lithium geometries). Refactor naming of conflicting data structures. Update .gitignore.

PG-PuReMD: fix error due to function prototype change. PuReMD: fix issues with GCC new inline behavior, fix reax_list bugs. sPuReMD: change exit code to zero.

sPuReMD: add safe memory allocation functions. Fix issue with certain parameters for shielded van der Waals interactions not being correctly initialized. Other general refactoring.

sPuReMD: further OpenMP work on force computations and interaction lists. Minor data structure scope changes. Fix numereous non-critical memory leaks. Add tear-down code. Other general refactoring.

Add minor checks to PG-PuReMD and PuReMD. Major refactoring of sPuReMD: backport much of PuReMD code and add CUSTOM geo format.