IO

Ramannoodle includes functions for reading and writing files used by quantum chemistry software. Currently, ramannoodle includes build-in interfaces with VASP. Ramannoodle also includes an interface with pymatgen, allowing spectra to be calculated using a wide array of DFT packages.

File IO

IO operations are implemented in ramannoodle as functions. These are organized into packages and modules under ramannoodle.io. For example, VASP POSCAR IO functions are contained in ramannoodle.io.vasp.poscar while OUTCAR files can be read with functions in ramannoodle.io.vasp.outcar. Using this structure, files of various types can be interacted with in an intuitive and readable way:

import ramannoodle as rn

phonons = rn.io.vasp.outcar.read_phonons(...)
rn.io.vasp.poscar.write_structure(...)

Ramannoodle also includes generic versions of IO functions in ramannoodle.io.generic. These functions use parameters to specify the desired file format:

import ramannoodle as rn

phonons = rn.io.generic.read_phonons(..., file_format = "outcar")
rn.io.generic.write_structure(..., file_format = "poscar")

These generic functions are less flexible than those first mentioned, and therefore these generic functions are best used only when necessary. One such case is loading files directly into polarizability models:

import ramannoodle as rn

model = rn.pmodel.InterpolationModel(...)
model.add_dof_from_files(..., file_format = "outcar")

InterpolationModel.add_dof_from_files() and other methods like it rely on these generic methods, as apparent from the file_format argument.

Supported file formats

The following table reviews which file types and properties are currently supported by ramannoodle’s IO functions:

File format (file_format)	ReferenceStructure	Phonons	Trajectory	positions	polarizability
POSCAR ("poscar")	read/write			read/write
OUTCAR ("outcar")	read1	read	read	read1	read
XDATCAR ("xdatcar")	read1/write		read2/write	read1/write
vasprun.xml ("vasprun.xml")	read1	read	read	read1	read

¹ Uses initial structure. ² Not available in ramannoodle.io.generic

Pymatgen integration

Ramannoodle includes interfaces with pymatgen. By taking advantage of pymatgen’s IO functionality, one can use ramannoodle with a wide variety of popular DFT software packages. ramannoodle.io.pymatgen contains various useful functions for loading pymatgen data into ramannoodle. In addition InterpolationModel and ARTModel implement add_dof_from_pymatgen() and add_art_from_pymatgen() methods, allowing one to build up these models using pymatgen objects.