Abstract: An arithmetic device calculates the surface potential of a silicon layer by performing computation based on a mathematical expression and device parameters stored in a storage device. Likewise, the arithmetic device calculates the surface potential of a bulk layer under a buried oxide film when the silicon layer is in a partially depleted state and when the silicon is in a fully depleted state. The arithmetic device then performs computation based on the calculated surface potential of the silicon layer, the calculated surface potential of the bulk layer, and mathematical expressions stored in the storage device, and obtains the surface potential of the bulk layer by iterative calculation. The arithmetic device performs computation based on the surface potential of the bulk layer obtained by iterative calculation and mathematical expressions stored in the storage device, and calculates the lower surface potential of the silicon layer.

Abstract: In a boundary active only scheme proposed by the present invention, only a cell in a boundary of region growth is brought into an active mode, and the other cells are brought into a standby mode. The respective cells perform state transition in parallel, and decision of the state transition performed for each clock cycle is not performed in a case where any of the three conditions that none of the adjacent cells is ignited, the cell itself is already ignited, and the cell already belongs to a certain divided region is satisfied. Therefore the number of simultaneously operating cells and that of coupling weight registers are minimized, and control is automatically executed to reduce power consumption.