Solving the Kohn-Sham eigenproblem within a common library approach to software development in electronic structure

Event Sponsor: 
Argonne Leadership Computing Facility Seminar
Start Date: 
Jan 21 2016 - 10:00am
Building/Room: 
Building 240/Room 4301
Location: 
Argonne National Laboratory
Speaker(s): 
Fabiano Corsetti
Speaker(s) Title: 
Imperial College London
Host: 
Alvaro Vazquez Mayagoitia

The Electronic Structure Library (ESL) is a new initiative to create an online repository of software for use within electronic structure codes. One of the aims of the ESL is to give members of the community access to a diverse range of Kohn-Sham (KS) eigensolvers, in the form of fully functioning libraries. We focus on the libOMM library implementing the orbital minimization method (OMM), and explore the possibilities for using this method as an exact cubic-scaling solver for the self-consistent KS problem, comparing its performance with that of explicit diagonalization in realistic systems. We discuss its efficiency for codes using a basis of non-orthogonal finite-range atomic orbitals, showing that the OMM can achieve a noticeable speedup with respect to diagonalization even for minimal basis sets for which the number of occupied eigenstates represents a significant fraction of the total basis size. Finally, we discuss the possibility of making use of the natural sparsity of the operator matrices for this type of basis, leading to a method that scales linearly with basis size.

Miscellaneous Information: 

Bio: Fabiano is a Research Associate in the Department of Materials at Imperial College London and the Thomas Young Centre for Theory and Simulation of Materials, working in the groups of Prof. Peter D. Haynes and Dr. Arash A. Mostofi. He received an MPhys in Theoretical Physics from the University of York, UK in 2008, working under the supervision of Prof. Rex Godby and Prof. Peter Bokes, and a PhD in Theory and Simulation of Materials from Imperial College London in 2012, working under the supervision of Dr. Arash A. Mostofi and Prof. W. Matthew C. Foulkes. He then moved to Spain to work as a postdoc at the CIC nanoGUNE institute in Donostia-San Sebastián in the Theory group of Prof. Emilio Artacho, before returning to London in 2015 to take up his current position. His interests are in ab initio methods for large- and multi-scale electronic structure simulations. He has contributed to the SIESTA and ONETEP codes for linear-scaling density-functional theory calculations, and has worked on several independent codes and libraries. He is also part of the core group of developers of the Electronic Structure Library (ESL) project. His applied research has focused on point defects in nanostructures, at interfaces and on surfaces, the first principles characterization of bulk and nanoconfined water, and the mechanical properties of protein complexes. His Erdős number is at most 6.

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