velph init template

The velph init command is used to prepare the velph.toml file. If no custom template is specified, a default template is applied. To specify a custom template, use the following command:

% velph init CELL_FILENAME PROJECT_FOLDER --template-toml velph-tmpl.toml [OPTIONS]

The velph-tmpl.toml file (which can have any file name) is similar to the velph.toml file. It can be created by modifying an existing velph.toml. However, a key difference is that velph-tmpl.toml may include an [init.options] section that is not present in velph.toml. This section allows you to define default values as substitutes for command-line options used with velph init, as described in the next section.

[init.options]

[init.options]
kspacing = 0.2
kspacing_dense = 0.1
max_num_atoms = 120

The [init.options] keywords correspond to command-line options for velph init. A value given on the command line overrides the one in [init.options]. To view the available options and their defaults, use:

% velph init --help

The recognized keywords are listed below. Each maps to the velph init command-line option of the same name (with underscores written as hyphens).

Keyword	Type	Default	velph init option
amplitude	float	0.03	--amplitude
cell_for_nac	str	"primitive"	--cell-for-nac
cell_for_relax	str	"unitcell"	--cell-for-relax
diagonal	bool	false	--diagonal
find_primitive	bool	true	--no-find-primitive
kspacing	float	0.1	--kspacing
kspacing_dense	float	0.05	--kspacing-dense
magmom	str	(none)	--magmom
max_num_atoms	int	(none)	--max-num-atoms
phelel_nosym	bool	false	--phelel-nosym
plusminus	bool or "auto"	true	--plusminus / --auto
primitive_cell_choice	str	"standardized"	--primitive-cell-choice
supercell_dimension	list[int] (3)	(none)	--dim
supercell_matrix	list[int] (9)	(none)	--supercell-matrix
symmetrize_cell	bool	false	--symmetrize-cell
tolerance	float	1e-5	--tolerance
use_grg	bool	false	--use-grg

Notes:

• cell_for_nac and cell_for_relax accept "primitive" or "unitcell".

• primitive_cell_choice accepts "standardized" or "reduced".

• max_num_atoms determines the supercell dimension and must be used together with symmetrize_cell.

• Give either supercell_dimension (three integers) or supercell_matrix (nine integers), not both.

• The file-handling options of velph init (--force, --template-toml, --toml-filename) are command-line only and have no [init.options] keyword.

[vasp.incar]

In a template, the [vasp.incar] section holds the base INCAR settings that are common to the whole project, such as the plane-wave cutoff and the parallelization tags:

[vasp.incar]
encut = 400
ncore = 4
gga = "PS"

At velph init these base settings are merged into every [vasp.CALC_TYPE.incar] of the generated velph.toml. The calculation-type defaults and any [vasp.CALC_TYPE.incar] settings written in the template take precedence over them. See INCAR settings for the full merge, override, and suppression rules, including how the merge happens only at initialization.