DFT is ab initio relative to other more empirical methods like molecular mechanics. As pointed out by several people already, some information can be found elsewhere, as in here. ... In DFT, DFAs and wavefunction methods, the integrals can be computed, and hence, these methods are ab initio.

Which method is an ab initio method?

Ab initio methods, as the name implies, require no empirical information about the molecular system being considered but rather apply various approximations to solve Schrödinger's equation through the use of wave functions to describe atomic orbitals for the calculation of molecular properties.

Is DFT a variational method?

DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry.