Improving the efficiency of FP-LAPW calculations. Nature of problem: For ab-initio studies of the electronic and magnetic properties of poly-atomic systems, such as molecules, crystals and surfaces. Solution method: The full-potential linearized augmented plane wave (FP-LAPW) method is well known to enable accurate calculations of the electronic structure and magnetic properties of crystals [2,3,4,5,6,7,8,9,10,11,12]. Within the supercell approach it has also been used for studies of defects in the bulk and for crystal surfaces.