A data configuration process is repeatedly performed at least twice, and a sum of a value obtained by multiplying a difference between a first temporary value (PAjt=1) of element data obtained by the first data configuration process and a second temporary value (PAjt=2) of the element data obtained by the second data configuration process by a predetermined proportionality coefficient γ and the first temporary value (PAjt=1) is calculated for each of M sections A1 to AM as values approximated to a convergence value of the element data. By this, the number of times the data configuration process is repeatedly performed is considerably reduced when compared with a case where a convergence value of element data is obtained by repeatedly performing the data configuration process a number of times.