mpirun -np 4 build_path/bin/qmcapp input-xml
- If OpenMP is enabled, make sure to set OMP_NUM_THREADS. On many systems, the default OMP_NUM_THREADS is set to the maximum allowed number of threads per SMP node.
- Consult your system documentation for MPI jobs.
Before running QMCPACK
We can seldom write down the many-body trial wavefunction from scratch. The most general scenario follows
- run
DFT/HF or beyond HF calculations to obtain single-particle orbitals
(typical KS orbitals) or coefficients of multi determinants.
- extract the Fermion wavefunctions run VMC/Optimization run DMC or RQMC
Preparing input files
The
input XML for qmc sections are extremely simple. The major difficulties
concern trial wavefunctions. The components of a trial wavefunction can
be divided into
- Jastrow functions: one, two, and three (no four body yet)
- Fermion wavefunction: Slater determinant, Geminal
Jastrow functions are rather simple but have to be defined by users.
On
the other hand, users seldom have to prepare Fermion wavefunctions.
They are extracted from outputs of third-party packages by tools (See
QMCToolsHowTo).
Users may have to modify the name or id of the wavefunctions but again
this can be achieved by command-line options for the tools.
We have not implemented backflow wavefunctions but think we can use Jastrow/Fermion to represent them.
Electronic structure packages QMCPACK can utilize
- Gaussian
- Gamess (XML version)
- Casino (only for Gaussian basis set)
- Quantum espresso
- abinit
- qbox
Potentially, these packages will be supported
Often,
we can use utilities for Casino package but a preferred way is to work
with the packages directly if they are under open-source licenses. For
example, a postprocessing code pw2qmcpack.F90 for Quauntum espresso is
implemented using their libraries and HDF5 library.
