Skip to main content
This is a pre-production deployment of Warehouse. Changes made here affect the production instance of PyPI (pypi.python.org).
Help us improve Python packaging - Donate today!

A fast parser of XML files output by VASP DFT code written in Cython.

Project Description

Quantum Esperanto is a fast parser of XML files output by DFT codes (vasp as of now) written in Cython. It takes advantage of lxml, a Python wrapper around libxml2 library, and its Cython interface. XML files are parsed to a Python dictionary in a transparent way. It is really fast, up to 10 times faster than the parser used by pymatgen project.

Installation

As Quantum Esperanto is not yet on PyPI, it can be installed from GitHub:

$ git clone https://github.com/tilde-lab/quantum_esperanto
$ cd quantum_esperanto
$ pip install .

The Python prerequisites for the package are numpy and lxml (should be installed automatically with pip). Also, C compiler such as gcc must be present in the system.

It is possible to install the package in development mode. This will install Cython as well as nose test suite. To do it issue the following command after cloning the repository and changing the directory:

$ cd quantum_esperanto
$ pip install -e .[dev]

After install it is possible to run several tests to check if the installation was completed successfully. It can be done with the following commands in quantum_esperanto directory:

$ python setup.py test

If everything is OK, you’re all set to start using the package.

Usage

The parser can be used in a very simple way. First, the parser has to be instantiated, and then the parse_file method of the parser returns the dictionary of parsed values:

from quantum_esperanto.vasp import VaspParser
parser = VaspParser()
d = parser.parse_file('vasprun.xml')

The possible arguments for the parser are:

recover
(boolean, default: True) a flag that allows recovering broken XML. It is very useful in case of unfinished calculations; however, it exits on the first XML error and the returned dictionary contains parsed values up to the first XML error only. When XML recovery is needed, a warning is printed to stderr.
whitelist
(list, default: None) the list of parent tag names that are only needed to parsed. If None, then all tags are parsed.

Parsing result

The result of parsing is a dictionary that follows the structure of vasprun.xml. The keys of the dictionary are either tag names (for i, v, varray tags), or tag:tag name construction (for tags that do have name attribute), or just tags themselves. The values are either tag contents converted to the right type (specified by type tag attribute) or (in case of varrays and sets) Numpy arrays. Fortran overflows (denoted by *****) are converted to NaNs in case of float values and to MAXINT in case of integer values.

Example:

xml file

<structure name="primitive_cell" >
 <crystal>
  <varray name="basis" >
   <v>       1.43300000       1.43300000       1.43300000 </v>
   <v>       1.43300000      -1.43300000      -1.43300000 </v>
   <v>      -1.43300000       1.43300000      -1.43300000 </v>
  </varray>
  <i name="volume">     11.77059895 </i>
  <varray name="rec_basis" >
   <v>       0.34891835       0.34891835       0.00000000 </v>
   <v>       0.34891835      -0.00000000      -0.34891835 </v>
   <v>      -0.00000000       0.34891835      -0.34891835 </v>
  </varray>
 </crystal>
 <varray name="positions" >
  <v>       0.00000000       0.00000000       0.00000000 </v>
 </varray>
</structure>

resulting dictionary (printed with pprint):

{'structure:primitive_cell': {'crystal': {'basis': array([[ 1.433,  1.433,  1.433],
                                                          [ 1.433, -1.433, -1.433],
                                                          [-1.433,  1.433, -1.433]]),
                                          'rec_basis': array([[ 0.34891835,  0.34891835,  0.        ],
                                                              [ 0.34891835, -0.        , -0.34891835],
                                                              [-0.        ,  0.34891835, -0.34891835]]),
                                          'volume': 11.77059895},
                              'positions': array([[ 0.,  0.,  0.]])}}

License

Quantum Esperanto is licensed under MIT license.

Release History

Release History

This version
History Node

0.2

Download Files

Download Files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

File Name & Checksum SHA256 Checksum Help Version File Type Upload Date
quantum_esperanto-0.2.tar.gz (148.1 kB) Copy SHA256 Checksum SHA256 Source Nov 5, 2017

Supported By

WebFaction WebFaction Technical Writing Elastic Elastic Search Pingdom Pingdom Monitoring Dyn Dyn DNS Sentry Sentry Error Logging CloudAMQP CloudAMQP RabbitMQ Heroku Heroku PaaS Kabu Creative Kabu Creative UX & Design Fastly Fastly CDN DigiCert DigiCert EV Certificate Rackspace Rackspace Cloud Servers DreamHost DreamHost Log Hosting