CONQUEST is a computer simulation program to perform linear-scaling first-principles calculations of materials. Using density functional theory (DFT), it can simulate a wide range of properties of materials proprieties including energetics, structure at the atomic level and molecular dynamics, with a computational cost which scales only linearly with system size (in contrast to more conventional DFT implementations, which scale cubically).

CONQUEST's linear scaling is achieved by computing the single-particle density matrix, rather than the single-particle wavefunctions. This density matrix is expressed in a compact "fireball" basis, comprised of functions strictly localised within atom-centred spheres, and basis functions are coupled via a density-matrix kernel. The linear scaling is achieved by truncating the density kernel at a fixed distance.

The linear scaling of CONQUEST calculations makes it particularly suitable for DFT calculations of large systems, and CONQUEST has been used successfully to study systems of tens of thousands of atoms.

For more information on CONQUEST, see the dedicated CONQUEST website.