Task Level Parallelism

Taskfarming was introduced to the CRYSTAL code as part of this dCSE project. This functionality is essential for the use of the D&C algorithm. Finding the electronic structure of subsystems sequentially is comparatively highly inefficient. There are several other problems that will benefit from taskfarming being available in CRYSTAL. Notably, CRYSTAL computes the second derivative of the potential energy surface with respect to atomic positions using numerical finite differences in order to compute vibrational frequencies and phonon dispersion. This task is ideally suited to a taskfarming strategy to achieve maximal speed up on HPC resources. The utilisation of the taskfarming code introduced as part of this dCSE project is being investigated by Matteo Ferabone at Torino University, Italy.

Many scientific problems are studied by finding and comparing the electronic structure of many similar arrangements of atoms. For example, collaborators at Imperial College London have produced phase diagrams for chalcopyrites as the chemical potential of the constituent elements is varied. This sort of computation, where many similar but independent computations need to be performed may benefit from the task level parallelism introduced as part of this dCSE project.