Hybrid system simulation method and simulation program prduct

5) A discrete system simulation program product that simulates the behavior of a discrete system constituting a hybrid system together with a continuous system while communicating with a continuous system simulation program that simulates the behavior of the continuous system, the discrete system simulation program product causing a computer to execute the steps of:

• processing an event that occurs at the current time;
• sending a request for evaluation of an event generating conditional expression evaluated by referring to the value of at least one continuous system variable among multiple continuous system variables, which are variables describing the continuous system to the continuous system simulation program, in response to the end of the processing of the event;
• receiving current time data indicating the time when the result of evaluation of the event generating conditional expression indicates true and the value of at least one continuous system variable referred in simulation of the discrete system among the multiple continuous system variables from the continuous system simulation program;
• recording the value of at least one continuous system variable received from the continuous system simulation program to a storage section of the computer;
• and
• updating the current time with the received current time data.

10) A simulation program product for a hybrid system including a discrete system simulation program that simulates the behavior of a discrete system constituting the hybrid system and a continuous system simulation program that simulates the behavior of a continuous system constituting the hybrid system while communicating with the program, wherein:

• (a) the discrete system simulation program causing a computer to execute the steps of:
• processing an event that occurs at the current time in the discrete system;
• and
• handing over a request for evaluation of an event generating conditional expression evaluated by referring to the value of at least one continuous system variable among multiple continuous system variables, which are variables describing the continuous system to the continuous system simulation program, in response to the end of the processing of the event;
• (b) the continuous system simulation program causing the computer to execute the steps of:
• repeating simulation of advancing the current time of the continuous system by a step time interval and evaluation of the event generating conditional expression until evaluation of the event generating conditional expression indicates true, in response to the receiving of the request for evaluation;
• and handing over the value of current time data indicating the current time in the continuous system and the value of at least one continuous system variable referred to in simulation of the discrete system among the multiple continuous system variables to the discrete system simulation program, in response to evaluation of the event generating conditional expression indicating true;
• and
• (c) the discrete system simulation program further causing the computer to execute the steps of:
• updating current time data indicating the current time in the discrete system with the value of the current time data received from the continuous system simulation program;
• and
• processing an occurred event by referring to the value of at least one continuous system variable, which has been received from the continuous system simulation program, in response to update of the current time data.

11) A continuous system simulation method for simulating the behavior of a continuous system constituting a hybrid system together with a discrete system while communicating with a discrete system simulator that simulates the behavior of the discrete system, the method being executed by a computer, and the method comprising the steps of:

• the computer receiving a request for evaluation of an event generating conditional expression for an event to be processed by the discrete system simulator from the discrete system simulator, wherein the event generating conditional expression is evaluated by referring to the value of at least one continuous system variable among multiple continuous system variables describing the continuous system;
• the computer repeating simulation of advancing the current time of the continuous system by a step time interval and evaluation of the event generating conditional expression until evaluation of the event generating conditional expression indicates true, in response to the receiving of the request for evaluation;
• and
• the computer sending current time data indicating the current time and the value of at least one continuous system variable referred to in simulation of the discrete system among the multiple continuous system variables to the discrete system simulator, in response to evaluation of the event generating conditional expression indicating true.

12) A discrete system simulation method for simulating the behavior of a discrete system constituting a hybrid system together with a continuous system while communicating with a continuous system simulator that simulates the behavior of the continuous system, the method being executed on a computer, and the method comprising the steps of:

• the computer processing an event that occurs at the current time;
• the computer sending a request for evaluation of an event generating conditional expression evaluated by referring to the value of at least one continuous system variable among multiple continuous system variables, which are variables describing the continuous system to the continuous system simulator, in response to the end of the processing of the event;
• the computer receiving current time data indicating the time when the result of evaluation of the event generating conditional expression indicates true and the value of at least one continuous system variable referred in simulation of the discrete system among the continuous system variables from the continuous system simulator;
• the computer recording the received value of at least one continuous system variable to a storage section of the computer;
• and
• the computer updating the current time with the received current time data.