fchic

fchic is a tiny library for parsing Gaussian formatted checkpoint files into python data structures. To use it, simply point it at a file and give it a deck to load, like so:

import fchic

with open("data.fchk", "r") as f:
    out = fchic.deck_load(f, "Cartesian Gradient")

out is now a list of 3 x N floating point numbers parsed from the Cartesian Gradient section of data.fchk.

Note: fchic does no data validation (beyond shape and type), no physical unit conversions and no integration into fancy data structures. It is entirely a single page, simple pyparsing grammar. You'll need to do your own data processing from its outputs.

Usage

fchic consists of two functions:

• fchic.load(fp) transform a formatted checkpoint file in from a file-like object fp into a python dictionary of decks.
• fchic.deck_load(fp, name) loads the specific deck name from file-like object fp.

Versions of those functions that acts on strings (fchic.loads() and fchic.deck_loads) are also provided.

Decks are returned thinly parsed from the formatted checkpoint files:

• Integer values (type I) are parsed into lists of python int.
• Real values (type R) are parsed into lists of python float.
• Char values (type C) are parsed into a unary list containing a string.

Python is not exactly fast, and neither is pyparsing, so you'll generally want to use fchic.deck_load() which does not have to parse the whole file, and is therefore way way 🐇 faster 🐇.

Installation

pip install fchic

License

fchic is provided under the MIT license.