arXiv subjects

Alexey Neelov

Publications and source records attributed to Alexey Neelov.

7 recordsLinked to original sources

arXiv2009

Density Functional Theory calculation on many-cores hybrid CPU-GPU architectures

The implementation of a full electronic structure calculation code on a hybrid parallel architecture with Graphic Processing Units (GPU) is presented. The code which is on the basis of our implementation is a GNU-GPL code based on Daubechies wavelets. It shows very good performances, systematic convergence properties and an excellent efficiency on parallel computers. Our GPU-based acceleration fully preserves all these properties. In particular, the code is able to run on many cores which may or may not have a GPU associated. It is thus able to run on parallel and massive parallel hybrid environment, also with a non-homogeneous ratio CPU/GPU. With double precision calculations, we may achieve considerable speedup, between a factor of 20 for some operations and a factor of 6 for the whole DFT code.

cond-mat.mtrl-sci↗

arXiv2009

Structural stability of the $B_{80}$ fullerene against defect formation

Using a systematic search algorithm we identify several types of point defects in the boron fullerene with 80 atoms. All these point defect leave the cage structure intact. In addition the cage structure is also very stable with respect to elastic deformations and addition or removal of atoms.

cond-mat.mtrl-sci↗

arXiv2008

Structural fuzziness of large gold clusters

The energetic ground state of gold clusters with up to 314 atoms consists of rather complicated geometries that have only a weak resemblance to the perfect icosahedra, decahedra and octahedra that are encountered for some magic numbers. The structure changes in most cases completely by the addition of a single atom. Other low energy structures are so close in energy that their Boltzmann weight is not negligible at room temperature.

cond-mat.mtrl-sci↗

arXiv2008

Daubechies wavelets as a basis set for density functional pseudopotential calculations

Daubechies wavelets are a powerful systematic basis set for electronic structure calculations because they are orthogonal and localized both in real and Fourier space. We describe in detail how this basis set can be used to obtain a highly efficient and accurate method for density functional electronic structure calculations. An implementation of this method is available in the ABINIT free software package. This code shows high systematic convergence properties, very good performances and an excellent efficiency for parallel calculations.

cond-mat.mtrl-sci↗

arXiv2007

A Particle-Particle, Particle-Density (P3D) algorithm for the calculation of electrostatic interactions of particles with slab-like geometry

We present a fast and accurate method to calculate the electrostatic energy and forces of interacting particles with the boundary conditions appropriate to surfaces, i.e periodic in the two directions parallel to the surface and free in the perpendicular direction. In the spirit of the Ewald method the problem is divided into a short range and long range part. The charge density responsible for the long range part is represented by plane waves in the periodic directions and by finite elements in the non-periodic direction. Our method has computational complexity of O(N_g log(N_g)) with a very small prefactor, where N_g is the number of grid points.

physics.comp-ph↗

arXiv2007

Particle-Particle, Particle-Scaling function (P3S) algorithm for electrostatic problems in free boundary conditions

An algorithm for fast calculation of the Coulombic forces and energies of point particles with free boundary conditions is proposed. Its calculation time scales as N log N for N particles. This novel method has lower crossover point with the full O(N^2) direct summation than the Fast Multipole Method. The forces obtained by our algorithm are analytical derivatives of the energy which guarantees energy conservation during a molecular dynamics simulation. Our algorithm is very simple. An MPI parallelised version of the code can be downloaded under the GNU General Public License from the website of our group.

physics.comp-ph↗

arXiv2006

Efficient solution of Poisson's equation with free boundary conditions

Interpolating scaling functions give a faithful representation of a localized charge distribution by its values on a grid. For such charge distributions, using a Fast Fourier method, we obtain highly accurate electrostatic potentials for free boundary conditions at the cost of O(N log N) operations, where N is the number of grid points. Thus, with our approach, free boundary conditions are treated as efficiently as the periodic conditions via plane wave methods.

cond-mat.mtrl-sci↗