Block bond-order potential as a convergent moments-based method

The theory of a novel bond-order potential, which is based on the block Lanczos algorithm, is presented within an orthogonal tight-binding representation. The block scheme handles automatically the very different character of sigma and pi bonds by introducing block elements, which produces rapid convergence of the energies and forces within insulators, semiconductors, metals, and molecules. The method gives the first convergent results for vacancies in semiconductors using a moments-based method with a low number of moments. Our use of the Lanczos basis simplifies the calculations of the band energy and forces, which allows the application of the method to the molecular dynamics simulations of large systems. As an illustration of this convergent O(N) method we apply the block bond-order potential to the large scale simulation of the deformation of a carbon nanotube.Comment: revtex, 43 pages, 11 figures, submitted to Phys. Rev.

Education and Research Challenges in Parallel Computing

Over three decades of parallel computing, new computational requirements and systems have steadily evolved, yet parallel software remains notably more difficult relative to its sequential counterpart, especially for fine-grained parallel applications. We discuss the role of education to address challenges posed by applications such as informatics, scientific modeling, enterprise processing, and numerical computation. We outline new curricula both in computational science and in computer science. There appear to be new directions in which graduate education in parallel computing could be directed toward fulfilling needs in science and industry