Employing the very fast simulated annealing (VFSA) global optimization technique, a FORTRAN program is developed for the interpretation of one-dimensional direct current resistivity sounding data various electrode arrays. The VFSA optimization depicts various good fitting solutions (models) after analyzing a large number of models within a predefined model space.-Employing the very fast simulated annealing (VFSA) global optimization technique, a FORTRAN program is developed for the interpretation of one-dimensional direct current resistivity sounding data　various electrode arrays. The VFSA optimization depicts various good fitting solutions (models) after analyzing a large number of models within a predefined model space.