JPH09245014A - Discrete event simulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily construct a model in the discrete event simulator of a system for managing events by using a table. SOLUTION: This discrete event simulator is provided with the definition data 108 of the model, an event table 106, an event selection means 101, an event-other-than-interruption processing means 104, a simulation time updating means 102, an interruption event sorting means 103, an interruption event processing means 105 and an event-to-be-interrupted table 107. Then, in the discrete event simulator, the interruption event sorting means 103 checks the event selected by the event selection means 101, the event to be interrupted to be the object of interruption is selected from the event table 106 and saved in the event-to-be-interrupted table 107 in the case of an interruption execution event and all the events to be released from the interruption to be the object of interruption release are selected from the event-to-be-interrupted table 107 and restored to the event table 106 in the case of an interruption release event.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simulation method and apparatus for designing and evaluating a plant, and more particularly to a discrete event simulator for simulating a physical distribution system handling discrete objects or an FA system.

[0002]

2. Description of the Related Art Models for simulating discrete events include event-centric models, process-centric models, and activity-centric models. The event-centric model is a model that describes a change in state at the time of occurrence of an event, and is represented by, for example, a state transition diagram. A process-centric model is a model that describes how things move in a system and is represented by a dataflow diagram. The activity-centric model is a model that describes the occurrence and termination of various states of the plant caused by an event, and there is no graphical representation that directly corresponds to this.

Discrete event simulators are often constructed against the background of such modeling methods, but in many cases they are realized by fusing event-centric models or activity-centric models with process-centric models. Has been done. That is, in terms of model representation, a model is often constructed by a data flow diagram, and internal processing often involves event-centric processing.

The prior art of the event driven type discrete event simulator which is the subject of the present invention will be described in more detail below with reference to FIGS. Here, the system of interest is described by a process-centric model, with a block diagram using special symbols such as time-delayed blocks. The block here is
In other parts of the specification, this corresponds to what is described as a place or an element.

FIG. 1 shows an example of a simulation target system model 1201 and its definition data 108 according to the prior art, and shows a model of a belt conveyor defined so that a "stop event" may occur. is there.

The model 1201 is a place where the model is 1211-1217 (synonymous with an element or a block).
It is information that is defined from the following and defines what kind of connection they have. This is defined by the user before starting the simulation, for example, by describing a data flow diagram representing the behavior of the system by a model creating means such as a visual programming language. The information thus obtained is converted by the preprocessor of the simulator into the definition data 108 of the model used during the simulation execution (conversion process 1
202).

Further, regarding a place (block element) forming a screen, what kind of processing is to be performed for which entrance is previously defined separately. Also, the name of the place is usually given to the place (block element) so as to reflect the processing.

FIG. 2 is a diagram showing an example of the structure of the event table 106. The conventional event table 106 includes a current event chain 310 and a future event chain 320. In the event table 106, as parameters constituting event data, the occurrence time 321 of the event, the identifier 322 of the process related to the event (such as the address of a subroutine of the process representing the event), the place 323 where the event occurs, and the event-related There is an area 324 in which information (or its identification ID) relating to things to be recorded can be recorded.

In the current event chain 310, the event occurrence time 321 is not essential. Further, when the information about the object is stored by its identification ID or the like, the table 330 for storing the information of the object is separately required. Here, the case of such an implementation method is shown as an example.

Furthermore, the description will be supplemented with respect to some points. The "thing related to the phenomenon" is, for example, "corrugated board" in the case where "the phenomenon that the corrugated board enters the conveyor" occurs, and the information about it is, for example,
When it is desired to collect the number of corrugated cardboards that have passed through the conveyor for each type and size by simulation, it is information indicating the type and size of each corrugated cardboard.

Next, an outline of a conventional discrete event simulator having the above-mentioned configuration will be described.

As shown in FIG. 3, for example, a conventional discrete event simulator includes an event selecting means 101, a simulation time updating means 102, and an event processing means 103, and the above-mentioned simulation target system model data (hereinafter referred to as definition data). (Abbreviated) 108 and the event data stored in the event table 106 are used to perform a simulation. The definition data 108 is information obtained by converting the information 1201 on the model screen into a form that can be processed by a computer. Here, the configuration on the model screen (see FIG. 1) is regarded as the model definition data 108. Explain.

Each location shown in the model has an entrance and an exit. For example, in the Delay element 1211 of FIG. 1, there is an inlet 1221 and an outlet 1222. Any place has at least one. For the event processing means 1101, the entrance or exit corresponds to the address of the function. Therefore, when an event occurs that an object enters the entrance of a certain place on the screen, the function corresponding to the entrance is called with the attribute value of the entered object as an argument.

For example, for the Delay element 1211 of FIG. 1, when an "event of arrival of an object" occurs at the entrance 1221, a time delay calculation process is performed, and based on the result of this calculation, an "event of an object exit". Decides the time when will occur, and this new event will be the future event chain 3
20. Also, for example, the Switch element 121
If it is 2, a function for performing a conditional judgment operation of the switch is called, and an “outgoing event” to either of two exits is stored in the current event chain 310.

From the events registered in the event table 106 based on the processing results of such various events, the event selecting means 101 selects the event with the earliest occurrence time and implements this as the next event. . If there is no selectable event in the current event chain 302, the simulation time updating means 102 reads the time of the event that should occur next from the future event chain 320 and sets it as the simulation time. Also,
All events that occur at that time are moved from the future event chain 320 to the current event chain 310.

In the conventional discrete event simulator, by repeating such processing, the "event that an object comes out" that has just entered is also processed, and the "event that an object comes in" is newly registered for the entrance of another place connected to the exit. And the time on the simulation goes on.

Most of the results of processing such as calculation are
Although it is stored in the table 330 regarding the information of the object flowing through the arc on the data flow diagram, only the calculation result regarding the occurrence time of the event is stored in the event table 106. In addition, events are roughly classified into the following four types. That is, there are a type in which an incoming event and an outgoing event occur without a time delay, a type that occurs with a certain time delay, a type that does not come in and out, and a type that only comes out.

The objects that flow along the block diagram of the conventional discrete event simulator described above are called transactions. Transactions are stored in one of two lists: (1) Future Event Chain and (2) Current Event Chain. (1)
In this list, transactions whose scheduled time to go out from the currently entered block is later than the current simulation time are stored in order from the earliest time to go out. In the list of (2), the transactions whose scheduled time to go out from the currently entered block are equal to the current time are arranged in order of priority and the like.

In the conventional discrete event simulator, when the processing of all transactions arranged in the list of (2) is completed, the event at the head of the list of (1) is selected and the simulation time is adjusted to that time. further,
All the events whose occurrence time is equal to the simulation time are selected from the list of (1) and moved to the list of (2).
From the head of the new current event chain created in this way, the simulation is advanced to the block whose dwell time is not 0 according to the connected block. At this time,
In the block where the residence time is not 0, the event is registered in the list of (1) as the time to go out by adding the residence time to the time.

As described above, the discrete event simulator is mainly realized by a process of registering a newly occurring event in a list or a table and a process of searching and executing the registered event.

Next, the above-mentioned event selecting means 101, simulation time updating means 102, and event processing means 1101.
An example of processing for realizing each of the above will be described.

First, a program example of processing for realizing the event selecting means 101 will be described with reference to the flowchart of FIG.

When the event selecting means 101 is activated, the simulation is not completed and the simulation time update request is made, and then it is confirmed whether or not the simulation is completed (step 401). If it is not finished, it is confirmed whether or not the simulation time update is completed (step 402), and if the update is completed, the event at the head of the current event chain 301 is searched and selected (step 403).

If there is a selectable event in the current event chain 301 (Y in step 404), the selected event is deleted from the current event chain 310 (step 406). In the case of N in step 404, a simulation time update request is issued to the simulation time update means 102 (step 405), and step 401
Is repeated.

Next, a program example of processing for realizing the event processing means 1101 will be described with reference to the flowchart of FIG.

When the event processing means 1101 is started, the simulation is not completed and the simulation time update request is not made, and it is confirmed whether or not the simulation is completed (step 601). If it is not completed, it is confirmed whether there is an event processing request (step 602),
If there is, the function is called and the processing is performed as described above (step 603).

As a result, it is determined whether or not a new event (derivative event) occurs (step 604). If there is a derivative event, a registration request for the derivative event is issued (step 605), and the process shown in FIG. From the definition data 108 of the model corresponding to the data flow diagram, the "event to be entered" to the place next to that place is indicated by the current event chain 31.
Register to 0.

For example, an "entering event" from the Delay element 1211 corresponds to an "entering event" into the Switch element 1212. At this time, time and related information (for example, multiplication result) are also registered. When a newly occurring event occurs without time delay, it is registered in the current event chain 310, and when there is a time delay, it is registered in the future event chain 320.

After that, the processing from step 601 is repeated again. Further, depending on the model definition data 108, there may be no event to be derived (N in step 604), but in that case, the processing from step 601 is immediately repeated again.

Next, a program example of processing for realizing the simulation time updating means 102 will be described with reference to the flowchart of FIG.

When the simulation time updating means 102 is activated, the simulation time is not completed and the simulation time update request is made. Next, the occurrence time of the first event of the future event chain 320 is set as the simulation time (step 1002). If the simulation time is equal to or longer than the simulation end time or there is no event to be selected (step 1003
Then Y), and the simulation ends. In other cases, all the events having the same occurrence time as the simulation time are selected from the future event chain 320 and moved to the current event chain (step 1004), and the simulation time update is completed.

As described above, in the conventional discrete event simulator, the event selecting means 101, the event processing means 1101, and the simulation time updating means 102 proceed with the simulation while sequentially accessing the model definition data 108 and the event table 106. .

[0033]

First, the problem to be solved will be described through an example. Here, consider the case where a cardboard is conveyed by a belt conveyor.

The belt conveyor is a place with a time delay from entering to leaving (Delay element 121 in FIG. 1).
1). In the conventional discrete event simulator, when an event of entering a cardboard occurs, the transportation time is considered and the event of exiting is registered. However, if it is attempted to simulate the stoppage of the conveyor while the corrugated board is being carried, it becomes quite difficult with the conventional discrete event simulator.

This is because the new event is stored only in the event table (hereinafter also including a list) and cannot be deleted from the event table until the event occurs. Therefore, even if the conveyor fails, the cardboard will be ejected. Therefore, in the case of a failure, the loop for returning the cardboard that has come out to the original conveyor again (elements 1211 to 1215 in FIG. 1)
Will need to be added.

The addition of such a loop not only causes a modeling error due to the unnaturalness of modeling, but also increases the calculation time.

The main problem to be solved by the present invention is to solve the problems that may occur in the conventional discrete event simulator as described above.

More generally, this problem will be described as follows. That is, some events may affect events that have been registered earlier but have not yet occurred. In order to model such an event, it is necessary to model the processing of this event so as to satisfy both the case of being affected and the case of not being affected. However, if they are to be modeled as they are, as in the prior art, there is a problem that the data flow diagram is complicated and the deviation from the actual plant image becomes large. Further, since the flow becomes long, the time required for calculation also increases.

Therefore, it is an object of the present invention to provide a discrete event simulator which can overcome the problems of the prior art described above, facilitate modeling, and reduce the load of arithmetic processing.

[0040]

In order to achieve the above object, the present invention provides an event-driven discrete event simulator for simulating a discrete event with event data composed of a plurality of data elements characterizing an event. In addition, first storage means for storing event data of a certain type of event, the occurrence of which is defined to affect another event, and the first storage means.
Selecting means for selecting an event to be performed next among the events whose data is stored in the storing means, and selecting means for identifying whether the event selected by the selecting means is the certain kind of event. When the selected event is identified as the certain type of event, the process corresponding to the operation preset as the operation to be performed by the event is not performed in the first storage unit. Operation means for the selected event data and processing means for executing processing according to the data of the event when the selected event is identified as a normal event other than the certain type of event Have and.

Further, in the above invention, the certain type of event includes at least an interrupt execution event for temporarily suppressing the occurrence of an event occurring at a place where the event occurs, and the operation means includes: A second storage unit for storing event data is provided, and when the interrupt execution event is selected, it is unselected from among the event data in the first storage unit and the occurrence of the interrupt execution event. Event data corresponding to events that occur at the same place as
It may be moved to the second storage means.

Further, in the above-mentioned invention, the certain type of event includes at least an occurrence time change event for changing an occurrence time of an event whose relation to the event is defined, and the operation means. When the occurrence time change event is selected, the occurrence time of the event that is not selected and is related to the occurrence time change event is selected from the event data in the first storage means. But it's okay.

Further, in the above invention, the certain type of event includes at least a clear event for deleting an event occurring at a place where the event occurs, and the operation means selects the clear event. In this case, of the event data in the first storage means, the event data of an event which has not been selected and which occurs at the place where the clear event has occurred may be deleted.

Further, in the above-mentioned invention, the simulator describes a system model to be simulated by a data flow diagram, and among the model elements corresponding to the place where the event occurs, which is included in the model described above. , At least one model element, in addition to at least one of an input point and an output point for instructing registration of an event in the first storage means, in addition to the occurrence of the certain type of event, the model It may further have an input point for instructing an operation to be performed on the event data of other events occurring in the element.

Further, in the above-mentioned invention, the certain type of event means that the occurrence of the event affects the occurrence of another event, and the operation means is unselected in the first storage means. Identifier data for identifying the event data affected by the certain type of event identified by the identifying means, and identifying the identified event data from other event data. It may be added to the identified event data.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention newly considers an event of a specific type that affects other events already registered in the event table, and mainly when the event occurs, This was done by paying attention to the fact that the place (element) where the event occurred affects only the event that is scheduled to occur.

The present invention is a discrete event simulator for performing simulation by managing events by an event table, and in a processing method for registering event data in the event table, for example, one of the places forming a simulation model An input is provided to temporarily suppress the occurrence of an event that occurs or to delay the occurrence of the event, and when a trigger for this input occurs, the event that will occur at that location is recorded from the original event table. Select all and move it to another newly created table.

Further, in the discrete event simulator according to the present invention, for example, an input for returning is also provided at the above-mentioned place, and when a trigger for the input occurs, it should occur again from the above-mentioned another table there. The event that was was returned to the original event table.

Further, in the discrete event simulator according to the present invention, for example, an input for erasing is also provided in the same place, and an event that should have occurred at the time when the input is triggered. Is deleted from the event table and deleted.

According to the above configuration, the model can be represented obediently by the data flow model, and the modeling becomes easy. That is, in the past, when a certain special event occurred, an event that would not originally occur will occur because it is already registered in the event table, and the problem will occur again in advance at the same place. It was necessary to add a flow to return the information and objects (related information) associated with the event to the same place again so that they could occur, but this is not necessary.

The present invention will be described more concretely by taking as an example a simulation relating to the process of carrying a corrugated board on a conveyor.

For example, when an event of conveyor stop occurs, the corrugated cardboard originally placed on it should be stopped at that position. However, in the conventional discrete event simulator using the event table, if the conveyor is modeled as a place that simply represents a time delay, the event that the cardboard comes out will occur regardless of the stop.

Therefore, at the same time as the occurrence of the failure, it is taken out of the place showing the above-mentioned time delay, the remaining transport time is calculated from the elapsed time until then, and the result is added to the information showing the object (cardboard), Store it in the buffer once. Next, when an event of conveyor return occurs, the information of the object (cardboard) in the buffer is taken out, the occurrence time of the conveyor return event is used as an offset, the remaining transfer time is added, and the conveyor is represented again, It is necessary to store the event of exiting the conveyor at the place indicating the time delay.

In the prior art, for example, as shown in FIG.
A set of elements having the above-described series of functions is defined as a conveyor. In this case, it is necessary to add new blocks such as a buffer, a branch, and a calculation in addition to a time delay element that represents the main characteristics of the conveyor. Therefore, even if the calculation process such as the calculation of the remaining transport time, which is necessary for the characteristics of the model, is the same, for the accompanying process,
The processing load on the entire simulation increases.

On the other hand, in the present invention, as the function of the time delay element, the simulation executing means has a function of moving information relating to an object (information) waiting for the passage of time to another table. Therefore, the number of locations handled does not increase and the processing load is reduced. Furthermore, since the table operation performed in the present invention is routine, it is possible to further optimize the processing and speed it up.

An embodiment of the discrete event simulator according to the present invention will be described below. It should be noted that the same configurations as those of the above-described conventional technique or configurations that are considered to be functionally equivalent in the present invention are denoted by the same reference numerals and detailed description thereof is omitted.

First, the outline of the simulator of this embodiment will be described with reference to FIGS. Here, FIG. 7 is a block diagram showing the configuration of the present embodiment, FIG. 8 is an explanatory view showing the main part of the model definition data 108 in the present embodiment, and FIG. 9 is the event table 106 and interrupted in the present embodiment. It is explanatory drawing with the event table 107.

As shown in FIG. 7, the discrete event simulator in this embodiment has the model definition data 108, the event table 106, and the event selecting means 1 as in the conventional technique.
01, non-interruption event processing means 104, and simulation time updating means 102.

The non-interruption event processing means 104 is
The content of the processing is the same as what is called the event processing means 1101 (see FIG. 3) in the above-mentioned conventional technology. Further, the model definition data 108 of the present embodiment is different from the related art in the characteristics of each of the places forming the model. For this reason,
Even though the entire function is the same, the information indicating the connection relation of places is different from the above-mentioned conventional technology.

In the present embodiment, an interrupt event is provided as the above-mentioned specific type of event, and means related thereto is provided in addition to the configuration common to the above-mentioned prior art.
Interrupt event selection means 103, interrupt event processing means 1
05 and an interrupted event table 107 are further included.

The above-mentioned conventional discrete event simulator can only delete the occurring event and register a new event with respect to the current event chain 310 or the future event chain 320. On the other hand, in the present embodiment, a function of excluding an event in which a registered event has not occurred yet from the current event chain 310 or the future event chain 320, and a function of re-registering an event once excluded are added. There are features.

The operation of each means of this embodiment for realizing the above-mentioned functions will be described.

In the present embodiment, the newly added interrupt event selection means 103 checks the event selected by the event selection means 101 and identifies whether or not it is an interrupt event. If the event is not an interrupt event, the processing may be performed in the same manner as in the prior art, and the data of the selected event is delivered to the non-interruption event processing means 104, and the non-interruption event processing means 104 processes as in the conventional example. On the other hand, in the case of an interrupt event, the event data is delivered to the interrupt event processing means 105 for processing.

The processing in the interrupt event processing means 105 is roughly divided into two types: interrupt execution and interrupt cancellation. In the case of an interrupt execution event, all interrupted events to be interrupted are selected from the event table 106, and these are selected.
(See FIG. 9). This prevents the event to be interrupted from being selected by the event selection means 101. Further, in the case of an interrupt release event, all interrupted release target events for interrupt release are selected from the interrupted event table 107, and these are selected in the event table 1.
Return to 06. As a result, the interrupted event is
Again, it becomes possible to be selected by the event selection means 101.

In this embodiment, for example, as shown in FIG. 8, a model of the belt conveyor is defined so that a "stop event" can occur. This model corresponds to the model of the conventional belt conveyor shown in FIG.

In this embodiment, an interrupt execution event or an interrupt release event is set as an event of a certain specific type as described above, and the entrances corresponding to these events are
It is added at the place where an interrupt event is generated.

For example, the Delay element 12 in the prior art.
11 (see FIG. 1), in the present embodiment, the inlet 23
A Delay element 211 to which 1 and 232 are added is provided. The entrance 231 is triggered by the Fail element 212 and corresponds to an interrupt execution event. Further, the entrance 232 is removed by the Repair element 213 and corresponds to an interrupt release event.

According to this embodiment, the user sets the trigger to the entrances 231 and 232 to generate the interrupt execution event or the interrupt cancellation event,
It is possible to cancel the occurrence of a registered event or to allow it to occur again.

Therefore, for example, when constructing a model of a conveyor having a stop function, the delay element 211 having the above-mentioned inlets 231 and 232 is used without constructing the feedback loop (1211 to 1215) as shown in FIG. As a result, the model can be easily constructed as shown in FIG.

Next, an example of the processing flow of each means 101 to 105 of the simulator of this embodiment for realizing the above-mentioned functions will be described.

The event selecting means 101 executes the processing described in FIG. 4, selects an event to occur from the current event chain 310 (step 403), and deletes the event (step 403). 406).
In this case, the processing is the same as in the prior art.

The interrupt event selection means 103 sets the state in which the simulation is not completed and the selection is completed at the time of its activation, and executes the processing as shown in FIG. 10, for example. the first,
Determining whether the simulation has ended (step 50
1) Further, it is judged whether the selection process is completed (step 502). If the simulation is not completed and the selection process is completed, step 503.
Then, it is determined whether the selected event is an event at the entrance / exit corresponding to the occurrence of a normal event (non-interrupt event) or an event at the entrance corresponding to the interrupt event. Next, a processing request corresponding to this determination result is sent to each corresponding means (steps 504 and 505).

When a normal event processing request is issued, the non-interruption event processing means 104, for example, as shown in FIG.
The following processing is executed. That is, the process related to the event is performed (step 603), and if there is a derived event (step 604), the event is registered in the current event chain 310 or the future event chain 320 (step 605). In this case as well, the processing is the same as in the prior art.

On the other hand, in the case of an interrupt (implementation / cancellation) event processing request, the interrupt event processing means 105, as shown in FIG. Performs a process. First, it is determined whether the simulation is completed (step 701) and whether there is an interrupt event processing request (step 702), and then step 70 is performed.
Proceed to 3. At step 703, the requested event is
The event at the entrance corresponding to the execution of the interrupt or the event at the entrance corresponding to the cancellation of the interrupt is identified. Finally, depending on the identification result, an interrupt execution process (step 704) or an interrupt release process (step 705) is executed.

Next, a detailed example of the interrupt execution processing of step 704 will be described with reference to FIG.

The entrance 231 (FIG. 8) corresponding to the interrupt event
If a trigger occurs in (see), that is, if a failure occurs, first, an event that occurs at the same place is selected from the current event chain 310 (see FIG. 9) (step 801). . Next, these selected events are moved to the interrupt event chain 340 (steps 802 and 803). At this time, when the next interrupt release event occurs, the waiting time after the interrupt release is set to 0 so that the selected event can be immediately returned to the current event chain 310 (step 80).
4).

Next, the future event chain 32
From 0 as well, events that similarly occur at that location are selected (step 805), and these selected events are moved to the interrupt event chain 104 (steps 806, 80).
7). At this time, the waiting time 341 after releasing the interrupt is
It is determined according to the following formula 1.

[0078]

[Equation 1] Wait time after interrupt release = (delay time) +
(Entered time)-(Interruption start time) Here, the first term on the right side is the time from the occurrence of the "entered event" to the occurrence of the "exited event", that is, the delay time of the processing corresponding to the event. . The second term on the right side is the time at which each "exit event" is registered, that is, the time at which the "enter event" corresponding to each "exit event" occurs.
The third term on the right side is the time when the interrupt event occurred.

The waiting time 341 after the interruption is released is one of the information of the interruption event chain 340, at the time of registering the event in the interruption event chain 340,
Add to the event data (step 808).

Next, a detailed example of the interrupt canceling process in step 705 will be described with reference to FIG.

When a trigger is generated at the entrance 232 corresponding to an interrupt release event, an event that occurs at the same place is first selected from the interrupt event chain 340 (step 901) with the trigger, and a wait after the interrupt is released. For events with time 0, the current event chain 3
Move to 10 (step 902).

Next, for an event in which the wait time after the interrupt is released is not 0, the time at which the event occurs is set to the time when the interrupt release event occurs and the time after the interrupt is released (step 904). ), Move to the future event chain 320 (step 90)
3, 905).

According to the above processing, the event selecting means 101
Allows the event that was temporarily out of the selection to be selected again from the current event chain 310 or the future event chain 320.

Next, an example of the overall processing in which the processing of each means of the discrete event simulator of this embodiment described above is summarized is shown in the flowchart of FIG.

First, each means of this simulator is initialized (step 1401). More specifically, it determines the simulation target system model data, registers the initial event in the event table, and sets the simulation end time.

Next, the event selecting means 101 searches the events registered in the event table and selects selectable events (step 1403). If the selection is possible (No in step 1403), the interrupt event selection means 103
Determines whether the selected event is an interrupt execution event or an interrupt release event or a normal event other than the interrupt event (step 140).
5, 1407, 1411).

If the event is an interrupt execution event (Yes in step 1407), the interrupt event processing means 105
, An event occurring at the place where the interrupt occurs, is extracted from the event table 106, and the interrupted event table 1
Move to 07 (step 1409). If it is an interrupt release event (Yes in step 1411), the interrupt event processing means 105 causes the interrupted event table 1
The event that should have occurred at the place where the interrupt occurred is taken out from 07 and moved to the event table 106 (step 1413). If it was a normal event,
The non-interruption event processing means 104 executes a process corresponding to the selected event based on the simulation target system model (step 1415).

Further, it is judged whether or not there is a derivative event (step 1417), and if there is a derivative event, the non-interruption event processing means 104 registers the derivative event in the event table 106 based on the simulation target system model. (Step 1419).

In the case of Yes at step 1403, the event selecting means 101 causes the simulation time updating means 10 to operate.
2 request simulation time update (step 1
404). In response to this request, the simulation time updating means 102 searches the events registered in the event table 106, and makes it possible to select an event that has not been selected and occurs at the earliest time (step 1406).

Further, it is judged whether the above selection is impossible or the occurrence time of the selected event is after the simulation end time (step 140).
8) If yes, end the simulation. Otherwise (No in step 1408),
The simulation time updating means 102 updates the simulation time (step 1410) and notifies the event selecting means 101 of the completion of the updating processing (step 141).
2).

According to the present embodiment, when an event originally scheduled to occur due to the occurrence of a special event does not occur temporarily, it can be generated again at the same place (element). , It becomes unnecessary to add a flow for returning the information or the object (related information) associated with the event to the same place (element) again. For this reason, the model can be more straightforwardly expressed by the data flow model, and there is an effect that the modeling becomes easy.

Further, according to the present embodiment, each means constituting the simulator does not have to deal with the place forming the flow and the occurrence of the event there, which is used in the conventional technique. Is less,
This has the effect of speeding up the simulation process.

Next, another embodiment of the discrete event simulator according to the present invention will be described with reference to FIG.

In the present embodiment, as an event of a certain specific type that affects other events, an "event to be cleared" is newly provided, and in defining the model, this event is defined as shown in FIG. A corresponding entrance 1504 is added to the place (element A) 1501 that should have the clear function. further,
In the model definition information, the connection relationship between the entrance 1504 and other places such as the CLEAR element 1505 is also set.

In the present embodiment, when a clear event occurs, all the events that should occur at that location are selected from the current event chain 310 or the future event chain 320 and are deleted.

According to this embodiment, the event selection means 101
However, when selecting a new event from the current event chain 310 or the future event chain 320, the event registered to occur at the place where the interrupt occurred will no longer be selected. By using the "clearing event" as described above, for example, it is possible to store a predetermined parameter and simulate a reset operation of a mechanical element that operates according to this. More specifically, in the case of an information communication system, it is possible to simulate an operation such as a power failure of a system that stores data related to an event, for example, data spooled to a printer server in a temporary storage device.

Next, still another embodiment of the discrete event simulator according to the present invention will be described with reference to FIG.

In this embodiment, the interrupt event chain 340 is not provided in the embodiment shown in FIG.
Instead, as shown in FIG. 16, a current event chain 310 and a future event chain 320
Are provided with flag areas 311 and 325 for identifying whether the event is an interrupt event.

In the present embodiment, when an interrupt execution event is selected, an interrupt event flag is set in the flag area of the interrupted event, instead of moving the interrupted event corresponding to it to the interrupt event chain 340. . Similarly, when the interrupt release event is selected, from the interrupt event chain 340,
Instead of returning to the current event chain 310 or future event chain 320, the interrupt event flag is cleared.

According to this embodiment, the event selection means 101
Sees this flag when selecting an event to be newly executed from the current event chain 310 or the future event chain 320, and if the flag is set, does not select it. Furthermore, when the interrupt event flag is cleared, the current event chain 31
If it is an event on 0, the occurrence time is the time at that time, and if it is an event on the future event chain 320, the value obtained according to the above equation 1 is added to the time at that time. Set.

According to this embodiment, the same effect as that obtained by the embodiment of FIG. 1 can be obtained without using the interrupt event chain 340.

[0102]

According to the present invention, it is possible to provide a discrete event simulator which can facilitate modeling and reduce the load of arithmetic processing.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a model definition of a conventional simulator.

FIG. 2 is an explanatory diagram showing a configuration example of a conventional event table.

FIG. 3 is a block diagram showing an example of the configuration of a conventional simulator.

FIG. 4 is a flowchart showing an example of a program that realizes an event selection unit.

FIG. 5 is a flowchart showing an example of a program that realizes an event processing unit.

FIG. 6 is a flowchart showing an example of a program that realizes a simulation time updating unit.

FIG. 7 is a block diagram showing a basic configuration and processing of a simulator according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram showing the definition of a model in the embodiment of FIG.

9 is an explanatory diagram showing a configuration example of an event table and an interrupted event table in the embodiment of FIG.

FIG. 10 is a flowchart showing an example of a program that realizes interrupt event selection means.

FIG. 11 is a flowchart showing an example of a program that realizes an interrupt event processing unit.

FIG. 12 is a flowchart showing an example of interrupt execution processing.

FIG. 13 is a flowchart showing an example of interrupt release processing.

FIG. 14 is a flowchart showing an overview of overall processing of the embodiment of FIG.

FIG. 15 is an explanatory diagram showing the definition of a model according to another embodiment of the present invention.

FIG. 16 is an explanatory diagram showing a configuration example of an event table and an interrupted event table in another embodiment of the present invention.

[Explanation of symbols]

101 ... Event selection means, 102 ... Simulation time updating means, 103 ... Interruption event selection means, 104 ... Out-of-interruption event processing means, 105 ... Interruption event processing means, 106 ... Event table, 107 ... Interrupted event table, 310 ... Current Event chain, 320 ...
Future event chain, 340 ... Interrupt event chain.

Claims (10)

[Claims] 1. An event-driven discrete event simulator for simulating a discrete event, in addition to event data consisting of a plurality of data elements characterizing an event, its occurrence is defined to affect other events. First to store event data for a particular type of event
Storage means, selecting means for selecting an event to be performed next among the events in which data is stored in the first storage means, and the event selected by the selecting means is the certain type of event. If the selected event is identified as the certain type of event, a process corresponding to an operation preset as an operation to be performed by the event, Operation means for performing unselected event data in the first storage means, and when the selected event is identified as a normal event other than the certain type of event, the event data is An event-driven discrete event simulator, comprising: a processing unit that executes processing according to the event. 2. The event according to claim 1, wherein the certain type of event includes at least an interrupt execution event that restricts the occurrence of another event that occurs at the place where the event occurs, and the operation unit includes: A second storage unit for storing event data is provided, and when the interrupt execution event is selected,
Of the event data in the first storage means, unselected,
An event-driven discrete event simulator, wherein event data corresponding to an event that occurs at the same place as the occurrence place of the interrupt execution event is moved to the second storage means. 3. The interrupt according to claim 2, wherein the certain type of event further includes an interrupt release event for releasing suppression by the interrupt execution event, and the operation unit selects the interrupt release event. The event driven discrete event simulator is characterized in that, in the case of being performed, the event data moved to the second storage means is moved to the first storage means. 4. The operation means according to claim 3, wherein the operation means moves the event data in the first storage means to the second storage means in accordance with a time at which the interrupt execution event occurs. An event-driven discrete event simulator characterized by changing an occurrence time indicated by the moving event data. 5. The operation according to claim 1, wherein the certain type of event includes at least an occurrence time change event that changes an occurrence time of an event whose relationship with the event is defined. The means, when the occurrence time change event is selected, changes the occurrence time of an event that is not selected from the event data in the first storage means and is associated with the occurrence time change event. An event-driven discrete event simulator characterized by the following. 6. The event according to claim 1, wherein the certain type of event includes at least a clear event that deletes an event occurring at a place where the event occurs, and the operation unit selects the clear event. In the event that the event occurs, the event data of the event which has not been selected and which occurs at the place where the clear event occurs is deleted from the event data in the first storage means. Event simulator. 7. The simulator according to claim 1, wherein the simulation target system model is described by a data flow diagram, and a model element corresponding to an occurrence location of an event included in the described model is included. Among them, at least one model element corresponds to at least one of an input point and an output point for instructing registration of an event in the first storage means, and corresponds to the occurrence of the certain type of event. An event-driven discrete event simulator, further comprising an input point for instructing an operation to be performed on event data of other events occurring in model elements. 8. The simulation target system model according to claim 7, wherein the simulation target system model includes at least a model element that simulates a time delay, and the model element that simulates the time delay occurs in the model element. An event-driven discrete event simulator characterized in that an input point for instructing stop and release of the function of the model element is added as an operation to the event data to be performed. 9. The event according to claim 1, wherein the certain type of event means that the occurrence of the event affects the occurrence of another event, and the operation unit is not yet stored in the first storage unit. Of the selected event data, the event data affected by the certain type of event identified by the identifying means is specified,
An event-driven discrete event simulator characterized by adding identifier data for distinguishing the specified event data from other event data to the specified event data. 10. In an event-driven discrete event simulator using a simulation target system model described by a data flow diagram, in addition to event data consisting of a plurality of data elements that characterize an event, its occurrence to another event. A storage unit for storing event data of an event of a certain specific type, which is defined as an effect, is included, and the described model includes a model element corresponding to the occurrence location of the event. At least one of them, in addition to at least one of an input point and an output point for instructing the registration of an event in the storage means, occurs in the model element in response to the occurrence of the certain type of event. Characterized by further having an input point for instructing an operation to be performed on the event data of other event Discrete event simulator of event-driven.