Thanks to the locality properties of wavelet functions implemented in the BigDFT code, we have achieved in 2015 a linear method which we applied to systems of many thousands of atoms. Other linear methods already existed but our method can be applied to a large class of materials with the same accuracy as the traditional one. The article, from which the cover is extracted, explains with details the algorithms used to perform the method on massively parallel computers.
A first target application will be the study of proteins. Our linear method can extract some local quantities as multipoles of atoms which can be useful to build polarisable force fields dedicated to the study of batteries or proteins. These local quantities are also useful to take into account the influence of a given environment on the studied system.