ASE Manual Release 3.6.1.2825 CAMd - CampOS Wiki

ASE Manual, Release 3.6.1.2828
.keyword.clear() Can be used on any option like calc.param.keyword.clear() or
calc.cell.keyword.clear() to return to the CASTEP default.
.initialize() Creates all needed input in the _directory. This can then copied to and run in a place
without ASE or even python.
.set_pspot(’’) This automatically sets the pseudo-potential for all present species to
_.usp. Make sure that _castep_pp_path is set correctly.
print(calc) Prints a short summary of the calculator settings and atoms.
ase.io.castep.read_seed(’path-to/seed’) Given you have a combination of
seed.{param,cell,castep} this will return an atoms object with the last ionic positions in the .castep
file and all other settings parsed from the .cell and .param file. If no .castep file is found the positions are
taken from the .cell file. The output directory will be set to the same directory, only the label is preceded
by ‘copy_of_’ to avoid overwriting.
Notes/Issues:
• Currently only the FixAtoms constraint is fully supported for reading and writing.
• There is no support for the CASTEP unit system. Units of eV and Angstrom are used throughout. In particular
when converting total energies from different calculators, one should check that the same CODATA
version is used for constants and conversion factors, respectively.
Example:
#!/usr/bin/python
"""This simple demo calculates the total energy of CO molecules
using once LDA and once PBE as xc-functional. Obviously
some parts in this scripts are longer than necessary, but are shown
to demonstrate some more features."""
import ase
import ase.calculators.castep, ase.io.castep
calc = ase.calculators.castep.Castep()
directory = ’CASTEP_ASE_DEMO’
# include interface settings in .param file
calc._export_settings = True
# reuse the same directory
calc._directory = directory
calc._rename_existing_dir = False
calc._label = ’CO_LDA’
# necessary for tasks with changing positions
# such as GeometryOptimization or MolecularDynamics
calc._set_atoms = True
# Param settings
calc.param.xc_functional = ’LDA’
calc.param.cut_off_energy = 400
# Prevent CASTEP from writing *wvfn* files
calc.param.num_dump_cycles = 0
# Cell settings
calc.cell.kpoint_mp_grid = ’1 1 1’
calc.cell.fix_com = False
calc.cell.fix_all_cell = True
7.14. Calculators 133