Wavelets for electronic structure calculations

In 2005, the EU FP6-STREP-NEST BigDFT project funded a consortium of four laboratories, with the aim of developing a novel approach for Density Functional Theory (DFT) calculations based on Daubechies wavelets. Rather than simply building a DFT code from scratch, the objective of this three-years project was to test the potential benefit of a new formalism in the context of electronic structure calculations. Daubechies wavelets exhibit a set of properties which make them ideal for a precise and optimised DFT approach. In particular, their systematicity allows to provide a reliable basis set for high-precision results, whereas their locality (both in real and reciprocal space) is highly desired for improve the efficiency and the flexibility of the treatment. In this contribution we will provide a bird's-eye view on the computational methods in DFT, and we then focus on DFT approaches and on the way they are implemented in the BigDFT code, to explain how we can take benefit from the peculiarities of such basis set in the context of electronic structure calculations.