Numerical codes: Computers and Programming ( actually used)
Numerical techniques: Ab-initio, theoretical quantum chemistry, quantum Hamiltonians, Quantum Monte Carlo, Exact Diagonalization.
1. Wien2k http://www.wien2k.at/index.html
2. Abinit http://www.abinit.org/
3. CASTEP http://www.tcm.phy.cam.ac.uk/castep/
4. DMol3 http://people.web.psi.ch/delley/dmol3.html
5. Gaussian http://www.gaussian.com/
6. SIESTA http://www.icmab.es/siesta/
7. VASP http://cms.mpi.univie.ac.at/vasp/
8. Elk FP-LAPW http://elk.sourceforge.net/