The Wolf summation is a method for computing the electrostatic interactions of systems (e.g. crystals). This method is generally more computationally efficient than the Ewald summation. It was proposed by Dieter Wolf. 
^Wolf, D; Keblinski, P; Phillpot, S R; Eggebrecht, J (1999). "Exact method for the simulation of Coulombic systems by spherically truncated, pairwise r^-1 summation". J. Chem. Phys. 110: 8254. Bibcode:1999JChPh.110.8254W. doi:10.1063/1.478738.