htesp.kpath

Module to handle kpath for high-symmetry lines

Functions

cut_path(path, kcutoff)

Keep the first kcutoff high-symmetry labels of path.

kpath(filename, npoint, kcutoff[, plot_bz, ...])

Function to write k-point mesh along the high-symmetry path of the Brillouin zone (BZ).

main()

Main function for executing different modes of k-point generation.

make_line_kpt([filename])

Function to create high symmetry points for line mode using pymatgen.

path_tokens(path)

Split an ASE band-path string into whole high-symmetry labels.

printk([out_dir, plot_bz])

Print k-point mesh within high-symmetry points and between them.
htesp.kpath.path_tokens(path)[source]

Split an ASE band-path string into whole high-symmetry labels.

'GXWK|UX' -> ['G', 'X', 'W', 'K', '|', 'U', 'X']. Separators are kept so that ''.join(tokens) reproduces the original path string.

Parameters:

path (str) – Band path as produced by cell.bandpath().path.

Returns:

Labels and separators, in order.

Return type:

list of str

htesp.kpath.cut_path(path, kcutoff)[source]

Keep the first kcutoff high-symmetry labels of path.

kcutoff <= 0 returns the full path. Separators never count as labels and a trailing separator is dropped.

Parameters:

  • path (str) – Band path as produced by cell.bandpath().path.

  • kcutoff (int) – Number of labels to keep.

Returns:

The truncated path string.

Return type:

str

Example

>>> cut_path("G1XWK|UX", 3)
'G1XW'
htesp.kpath.kpath(filename, npoint, kcutoff, plot_bz=False, bz_file='BZ.pdf')[source]

Function to write k-point mesh along the high-symmetry path of the Brillouin zone (BZ).

Parameters:

  • filename (str): Input file to read, which contains the structure or VASP ‘POSCAR’ file.

  • npoint (int): Size of k-point mesh.

  • kcutoff (int): Cutoff to use for k-point path in ASE. ‘0’ means full Brillouin zone, ‘n’ > 0 keeps only the first n high-symmetry labels of the BZ path.

  • plot_bz (bool): Write the Brillouin-zone sketch to bz_file. Default: False (see FIX(12); only printk turns it on).

  • bz_file (str): Output file for the BZ sketch. Default: ‘BZ.pdf’.

Returns:

  • kpoints (numpy.ndarray): K-mesh of size (npoint, 3).

  • sympoint (list): K-point in linear axis ready for plotting after processing.

  • symname (list): Naming for sympoint.

  • kpt (list): K-point in linear axis without processing.

  • spt (list): K-point in linear axis without processing at high-symmetry points.

  • sym (list): Naming for spt.

Example:

>>> kpoints, sympoint, symname, kpt, sym, spt = kpath("POSCAR", 100, 0)
htesp.kpath.printk(out_dir='scf_dir', plot_bz=True)[source]

Print k-point mesh within high-symmetry points and between them.

This function generates and prints k-points for quantum mechanics calculations, focusing on the Brillouin zone (BZ) and high-symmetry points.

Parameters:

  • out_dir (str): Directory the two .dat files are written to. Default: ‘scf_dir’. FIX(13): this used to be hard-coded, so a caller could not direct the output at a per-material directory.

  • plot_bz (bool): Write ‘BZ.pdf’ next to the output. Default: True, because the workflow harvests BZ.pdf from this call (see FIX(12)).

Returns:

None

Usage:

The function expects command-line arguments in the following order:

  • sys.argv[2]: Filename containing the structure or VASP ‘POSCAR’ file.

  • sys.argv[3]: Number of k-points.

  • sys.argv[4]: Cutoff for the k-point path in ASE. ‘0’ for the full Brillouin zone, ‘n’ to keep only the first n labels.

  • sys.argv[5]: Weight of the k-point.

  • sys.argv[6]: Output directory (optional, defaults to ‘scf_dir’).

Output:

The function generates two files in out_dir:

  • ‘kpathlines.dat’: Contains the k-point mesh within high-symmetry points and between them.

  • ‘kspecial-points.dat’: Lists the high-symmetry points.

htesp.kpath.make_line_kpt(filename='KPOINTS')[source]

Function to create high symmetry points for line mode using pymatgen.

This function generates high symmetry points for line mode using the provided structure file (“POSCAR”). The number of k-points for the line mode is specified by the second command-line argument.

Parameters: None

Returns: None

Usage: The function expects a command-line argument specifying the number of k-points for line mode.

Output: The function creates a KPOINTS file containing high symmetry points for line mode.

htesp.kpath.main()[source]

Main function for executing different modes of k-point generation.

Parameters: None

Returns: None