velph init

velph init with command options will generate modified velph.toml from the template.

% velph init [OPTIONS] CELL_FILENAME PROJECT_FOLDER

velph init --help shows short documents of the options. Two arguments have to be specified, POSCAR-format crystal structure and directory name that is created where velph.toml is stored. The available options are explained below. Some options can be specified in [init.options] section of the velph-toml template file (see velph init template).

velph init options

--template-toml

Using this option, velph.toml like file is read as the template instead of the template hard coded in velph code.

--tolerance

This is used for the symmetry check tolerance in Angstrom. Symmetry is searched always even without --symmetrize-cell.

--symmetrize-cell

By default (no-symmetrize), the input POSCAR-type structure is simply used as the unit cell. With --symmetrize-cell, input POSCAR-type structure is symmetrized and standardized conventional unit cell and primitive cell (“unitcell” and “primitive_cell”, respectively) are written in velph.toml.

--no-find-primitive

By this option, the input POSCAR-type structure is used as the primitive cell even if it is not a primitive cell.

--kspacing and --kspacing-dense

Sampling k-point meshes are calculated from these values in the similar way to VASP KSPACING definition by overwriting the template.

--max-num-atoms

Supercell shape is determined so that its number of atoms is equal or less than this number respecting the crystallographic point group. Use of this option requires --symmetrize-cell.

--dim

Supercell shape is determined by three integer values that extend along a, b, and c axes of the unit cell, respectively. See also --supercell-matrix.

--supercell-matrix

Supercell shape is determined by nine integer values (v1, …, v9) that corresponds to a 3x3 matrix [[v1, v2, v3], [v4, v5, v6], [v7, v8, v9]].

--cell-for-relax

This chooses unit cell or primitive cell for structure optimization (relax). The default is unitcell. Specify primitive to use primitive cell.

--cell-for-nac

This chooses unit cell or primitive cell for NAC calculation (nac). The default is primitive. Specify primitive to use primitive cell.

--primitive-cell-choice

Primitive cell choice, “standardized” (default) or “reduced”.

--use-grg

Use generalized regular grid.

--amplitude

Distance of displacements in Angstrom.

--diagonal

Whether to also generate displacements along diagonal (non-axis) directions. By default, only axis-aligned displacements are used. This corresponds to the diagonal key of [phelel], [phonopy], and [phono3py].

--plusminus / --auto

--plusminus (default) adds the opposite (minus) displacement for every displacement. --auto adds the minus displacement only when it is not symmetrically equivalent to the plus one. This corresponds to the plusminus key of [phelel], [phonopy], and [phono3py].

--phelel-nosym

Disable symmetry reduction of the displacements generated for the phelel supercell (equivalent to running phelel --nosym).

--magmom

String corresponding to INCAR MAGMOM tag value for unit cell, e.g., “24*1” or “0 0 1”. This is similar to MAGMOM tag in phonopy, see https://phonopy.github.io/phonopy/setting-tags.html#magmom. In velph, the asterisk symbol (*) is supported.

--force

Create velph.toml even if a file with the target name already exists, overwriting it.

--toml-filename

File name of the generated velph.toml-type file. The default is velph.toml.

Note

--force, --template-toml, and --toml-filename are command-line only and have no corresponding [init.options] keyword in the template file (see velph init template).