Patent ID: 7468510

Claim:
A coordinate difference calculation apparatus for calculating a coordinate difference between an i-particle and a j-particle included in one of a plurality of minute cells obtained by dividing a basic cell, comprising: a first storage section that stored in advance a coordinate value of said i-particle; a second storage section that stored in advance a value obtained by adding the length of one side of said basic cell to the coordinate of said i-particle; a third storage section that stored in advance a value obtained by subtracting the length of one side of said basic cell from the coordinate of said i-particle; a control section that outputs a selection signal to select a value in order to minimize a distance between a minute cell including said i-particle and a minute cell including said j-particle among values stored in said first to third storage sections and that outputs a coordinate value of said j-particle; a selection section that selects any one of the values stored in said first to third storage sections and outputs a selected value; and a computing section that subtracts the value output from said selection section from the coordinate value of said j-particle output from said control section.