Notes
This release includes new methods, converter updates, and many optimizations, feature improvements, and bug fixes. It is a recommended update for all users.
QMCPACK updates
- Support for finite difference linear response (FDLR) method and wavefunctions, developed and contributed by Nick Blunt and Eric Neuscamman, see Journal of Chemical Physics 147, 194101 (2017), https://doi.org/10.1063/1.4998197 and https://arxiv.org/abs/1707.09439 .
- Major update to convert4qmc, conversion from GAMESS and other gaussian basis set codes. HDF5 output is now supported for large wavefunctions with -hdf5 option. Significantly improved example inputs *.qmc.in.xml.
- Gaussian based trial wavefunctions now supported by structure of arrays implementation (ENABLE_SOA=1). A full reimplementation that will also support gaussians in periodic boundary conditions, e.g. from pyscf, is in progress.
- Initialization of multideterminant wavefunctions improved for faster startup and lower memory usage. In practice this significantly raises the usable maximum number of determinants.
- Maximum CPU time setting (maxcpusecs): QMC drivers will not start a new block if there is not enough estimated time remaining to complete the next block and gracefully shut down.
- Homogeneous electron gas wavefunction support and tests.
- New command line verbosity command line flag -verbosity. Output of QMCPACK will be overhauled over the next few releases to support low, high, and debug options, and also to significantly improve readability and utility.
- Bugfix: Umrigar drift diffusion term is now consistent with the Umrigar small time step error algorithm with complex wavefunctions.
- Bugfix: Momentum distribution is now correctly weighted and also correctly signed for twist averaging.
- Renamed performance tests with atom and electron count.
- Removed support for "buffering" of non-local pseudopotential wavefunction components during optimization (useBuffer setting) to reduce memory usage and for simplicity.
- doxygen documentation for developer-level documentation of the code and file structure. Produced via make in qmcpack/doxygen. HTML currently published at http://docs.qmcpack.org/doxygen/doxy/
- Many minor bug fixes and improved tests.
NEXUS
- Improved postprocessing support for Quantum Espresso.
- Various minor bug fixes.
Known issues and limitations
- Documentation, examples and tutorials are not yet consistent with the updated converter convert4qmc.
- Core functionality is largely compatible with ENABLE_SOA but some specialized wavefunctions and observables are not.
- Use of GNU compilers with glibc 2.23 builds will crash due to a bug in libmvec of glibc. The glibc version can be verified by "ldd --version".