PURPOSE: To eliminate the need of infinitely repeating a processing and to prevent a wasteful processing in a problem solution unit solving restriction shown by an inequality.
CONSTITUTION: A network control part 100 reads a restriction expression 102 and takes out a variable, and transfers the restriction expression and the variable to a network part 114. The node of the restriction expression and the variable is generated and it is connected with the other restriction expression node and variable node so as to constitute the network of restriction. A result is transferred to the network control part 110 and is stored in an inference result 108. A variable name, an upper limit value or a lower limit value being update information in the variable nodes which are transmitted till then are recorded and transmitted as a history except for the new upper limit value and the lower limit value in an update message with such constitution, and history is checked. When the update of the upper limit value and the lower limit value as against the same variable node is detected to be executed for more than the prescribed number of times, the processing of the update message is interrupted.
OHIRA EIJI
SHINJO HIROSHI
ABE MASAHIRO
