Pool-BCGA: a parallelised generation-free genetic algorithm for the ab initio global optimisation of nanoalloy clusters

Abstract

The Birmingham cluster genetic algorithm is a package that performs global optimisations for homo- and bimetallic clusters based on either first principles methods or empirical potentials. Here, we present a new parallel implementation of the code which employs a pool strategy in order to eliminate sequential steps and significantly improve performance. The new approach meets all requirements of an evolutionary algorithm and contains the main features of the previous implementation. The performance of the pool genetic algorithm is tested using the Gupta potential for the global optimisation of the Au10Pd10 cluster, which demonstrates the high efficiency of the method. The new implementation is also used for the global optimisation of the Au10 and Au20 clusters directly at the density functional theory level.

The Birmingham parallel genetic algorithm and its application to the direct DFT global optimisation of IrN(N = 10–20) clusters

“…30 The BPGA utilises a pool genetic algorithm methodology combined with the evaluation of potential cluster geometries in parallel. 31 Its predictions for Ag + 10 have also been shown to be accurate when compared with spectra from molecular beam experiments. The pool methodology has been recently applied to metallic clusters by Shayeghi et al 31 and was benchmarked and applied successfully to the global optimisation of the much studied Au 10 and Au 20 clusters.…”

“…This is achieved using the Birmingham Parallel Genetic Algorithm (BPGA), a new opensource genetic algorithm available via Bitbucket. The pool methodology has been recently applied to metallic clusters by Shayeghi et al 31 and was benchmarked and applied successfully to the global optimisation of the much studied Au 10 and Au 20 clusters. 25 This combination ensures highly efficient scaling when compared with generation based genetic algorithms and allows the structural characterisation of larger and more complex systems.…”

Application of a parallel genetic algorithm to the global optimization of medium-sized Au–Pd sub-nanometre clusters

“…Initially, the pool population is formed by generating a number of random isomers [41]. The ten generated structures forming the initial pool are geometrically relaxed by local DFT energy minimization [47]. Once minimized structures are generated, the genetic algorithm crossover and mutation operations are applied to members of the population.…”

“…In each run, multiple BPGA instances are implemented, and in each instance, a set of processes are run in parallel and independently [47,48]. Initially, the pool population is formed by generating a number of random isomers [41].…”

Communication: Global minimum search of ${\rm Ag}^+_{10}$ Ag 10+ with molecular beam optical spectroscopy

“…29 Initial cluster geometries are obtained by the Birmingham Cluster Genetic Algorithm (BCGA), 30 coupled with DFT (GADFT), 31 in a recently developed parallel pool modification. 32 The long-range corrected (LC) exchange correlation (xc) functional, LCωPBEh, 33 is used throughout our whole analysis. It has been shown to perform well for the calculation of ground and excited state properties of gold, 24,34 silver, 24 and mixed silver gold clusters, 35 where it leads to the reliable prediction of optical absorption spectra.…”