Calculation inputs¶

The generated input reference shows the exact templates at the documented revision. Copy the templates into a dedicated calculation directory so each log has a matching set of inputs.

Path in the calculation directory	Who writes it	Contents
mol/NAME.xyz	User or example setup	Geometry with an atom count and comment line. PyDuck defaults to Å
basis/BASIS	User or example setup	NWChem-format basis file. An explicit file path is also accepted
input/methods	User or example setup	Reference, method, and test flags
input/options	User or example setup	Numerical controls and method-specific choices
input/molecule	PyDuck	Electron counts and molecular data for the Fortran driver
int/	PyDuck	Nuclear repulsion, one-electron integrals, and electron-repulsion integrals

The Fortran readers interpret the main input records by position. Keep the template order and retain the header lines. Some optional records are recognized by their headers. The methods template lists standalone FTDA and FRPA above the test flags. Older files can keep that row below the test flags or omit it. A header can describe a flag even when a particular driver has no solver for it.

Common choices¶

Setting	What to record
Charge and multiplicity	PyDuck --charge and --multiplicity. Use --charge=-1 for a singly charged anion
Coordinate units	Å by default. Pass --bohr for bohr
SCF convergence	Maximum iterations, threshold, DIIS size, initial guess, and any level shift or orbital mixing
Response sector	TDA and the requested spin sectors. The restricted driver uses singlet/triplet labels. The unrestricted driver uses spin-conserving/spin-flip labels
Integral representation	Spherical or Cartesian basis, and formatted or binary two-electron integrals
Quasiparticle solver	Linearization, regularization, broadening, and any one-body self-consistency
Active orbital space	Frozen orbitals, CVS, and orbital occupations, as applicable to the method

The shipped value is the one used when you copy the template. A reader fallback applies only where the code allows an absent record. For example, an old two-switch Parquet methods record leaves GWParquet disabled. The optional standalone Faddeev record has its own fallback values, shown in the Faddeev guide. Driver-specific restrictions can further limit the combinations that run.

Reproduce a calculation¶

Save the source revision, geometry and its units, basis file, charge and multiplicity, input files, and output. For method development, also record the compiler, linked BLAS/LAPACK library, and whether the run used the standard or HPC driver. Use a separate working directory for every concurrent PyDuck run because it writes and replaces integral files.