PARAllel Total Energy Code

PARATEC is a package designed primarily for a massively parallel computing platform and can run on serial machines. The code performs ab-initio quantum-mechanical total energy calculations using pseudopotentials and a plane wave basis set. The pseudopotentials are of the standard norm-conserving variety (typically Hamann-Schulter-Chiang or Trouillier-Martins). Forces and stress can be easily calculated with PARATEC and used to relax the atoms into their equilibrium positions.

The total energy minimization of the electrons can be done by two methods. The more traditional self-consistent field (SCF) method utilizes Broyden, Pulay-Kerker or the newly developed Pulay-Kerker-Thomas-Fermi charge mixing schemes. In the SCF method, the electronic minimization is performed by unconstrained conjugate gradient algorithms on the Mauri-Galli-Ordejon (MGO) functional or the generalized Rayleigh quotient. The second method is a direct minimization (currently only implemented for systems with a gap) of the total energy. The new Hamiltonian, charge density, and total energy are calculated after every update of the electronic wavefunctions. A Grassman conjugate gradient algorithm is used in conjunction with the generalized Rayleigh quotient and a more standard conjugate gradient algorithm is used with the MGO functional.

The code is based (1990) upon the plane wave code of J.L. Martins. B. Pfrommer developed much of the code for his degrees. Ongoing work is excited-state calculations (Steven G. Louie) using the GW method with input from interfacing to Paratec. First-principle NMR calculations (Francesco Mauri) are also under development.

For instructions on running the code see PARATEC: User Guide. ( doc.pdf ) ( doc.ps ) ( doc.tex )

Analysis for particular systems and examples illustrating new methods and preferred settings is also provided.

CHANGES made in Recent Versions:

Future changes in a TODO list. List of machines on which Paratec runs.

Pseudopotential information

Relevant Publications

Developed through a joint collaboration between

LBNL: NERSC � Scientific Computing Group

Andrew Canning and David Raczkowski

LBNL: Material Sciences Division and UC Berkeley - Steven G. Louie and his group

Bernd Pfrommer, Young-Gui Yoon, Je-Luen Li,�

Other Contributors

LBNL:Material Sciences Division and UC Berkeley - Marvin L. Cohen and his group

David Roundy

Laboratoire de Min�ralogie-Cristallographie de Paris : Universit� Pierre et Marie Curie

Francesco Mauri and his group

University of Montreal - Michel Cot�

University of Cambridge - Theory of Condensed Matter Group

Jonathan Yates, Chris Pickard, and Peter Haynes

List of the Specific contributions of these people

Intended Users of PARATEC:

This code is primarily intended for users who are familiar with the plane-wave pseudopotential method used in PARATEC. The code is heavily optimized for running on large parallel machines such as the Cray T3E and IBM SP at NERSC.

Due to our limited resources for supporting PARATEC we cannot devote much of our time to helping people who are unfamiliar with the plane-wave pseudopotential method. Interested users of the code should familiarize themselves with this method by reading the literature before considering using the code.

Click here for the registration form. Please fax this form to us at (510) 486-5812

If you are interested in this package please contact David Raczkowski (DBRaczkowski@lbl.gov) or

Andrew Canning(Acanning@lbl.gov)