EFFECTIVE BLOCK EXTRACTION UNIT AND METHOD, AND A CIRCUIT SIMULATOR

Paths from a block that includes the node that is the object of analysis to another block are searched for by a path search section for all blocks in a circuit; and a depth judgment section finds the depth of each block from that path search information. An effective block judgment section compares the depth of each block to a specified depth that is stored in a specified depth storage section, and judges which blocks are effective blocks. Thus, blocks that include nodes that exert influence on the simulation accuracy at the node that is the object of analysis are extracted from the circuit that is the object of simulation as effective blocks. Then, in the circuit simulation, events are generated only for the effective blocks, and a transient analysis simulation is executed by the event-driven method. This permits the processing speed of the simulation to be increased while maintaining accuracy.