JPH06309295A - Discrete phenomenon simulation device - Google Patents

Abstract

PURPOSE:To attain the interruption and restart of simulation in the same way as the continuity of the simulation. CONSTITUTION:At the time of the start of the simulation, a simulation model described in a description form determined by a user is stored from an external storage device in a data base device 1 according to the storage form by using a state inputting means 5. When a phenomenon list is fetched from the data base device 1 by using a state reading means 2, a discrete phenomenon which occurs the earliest and an appropriate phenomenon routine are selected from the phenomenon list fetched from the data base device 1 by a phenomenon driving means 4 by using the state reading means 2, and the description of the state of the simulation model is rewritten by both the updating function and retrieval information managing function of the data base device 1 according to the content of the phenomenon routine by using a state rewriting means 3. At the time of interrupting the simulation on the way to the execution of the simulation, the entire state of the model is outputted in the form of the data base device by a state outputting means 6, and preserved in the external storage device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discrete event simulation device capable of easily interrupting and restarting a simulation.

[0002]

2. Description of the Related Art Discrete event simulation focuses only on an event that causes a change in the state of a system to be simulated (hereinafter, the event is referred to as an event), and a model of the system (hereinafter referred to as a simulation) is generated each time the event occurs. Call it a model) to change the state. An event routine is a representation of how the simulation model changes when an event occurs.

In a conventional discrete event simulation device, when performing a simulation, the structure of a simulation model is first described. Furthermore, if possible, the initial conditions of the simulation model are input. For example, the initial parameters and the initial state of the simulation model are input. In this case, the discrete event simulation device is provided with means for describing the structure and initial state of the simulation model. There are many things such as description means by network structure and programming language. These are referred to as simulation model description means or simply model description means.

The structure and initial conditions of the simulation model are described by such means, and these are input to the discrete event simulation device to start the simulation. When starting the simulation, the state of the simulation model is first described in the computer by the discrete event simulation device. In this case, the description means of the simulation model inside the computer (this is referred to as the internal description means) and the model description means for describing the initial input are different, so the model description means to the internal description means when reading into the computer. Convert. The state of the simulation model described inside the computer is invisible to the user. Further, the internal description means is not a description that the user can understand.

On the other hand, once the simulation starts, the total information of the simulation model held by the discrete event simulation apparatus becomes much larger than the initial input. This is because the simulation is performed while expressing each model element that moves around in the simulation model and collecting the resulting information.

By the way, when simulating a certain system, it is often required to predict statistical results and the future state (appearance) of the system. Therefore, the necessary statistical results are extracted and output from the states of the simulation model described by the internal description means.

If the simulation is for predicting the future appearance of the system, the final state of the simulation model is output. At the time when the simulation is completed, the simulation model is described by the internal description means. Here, after conversion into a description means that can be understood by the user, it is output (displayed on the screen or saved in a file). That is, it is necessary to convert the internal description means into a description means that the user can understand. By showing the final state of the simulation model after conversion, the future prediction of the system will be shown.

[0008]

As described above, in the conventional discrete event simulation apparatus, the model description means that the user can understand regarding the representation of the simulation model is different from the internal description means inside the computer.

By the way, when performing a long and large-scale simulation, it is sometimes desired to stop and restart the simulation. In order to stop and restart the simulation without interruption, all data of the state of the simulation model at the time of stopping must be saved. Further, when the simulation is stopped, the state of the simulation model is represented by the internal description means because the simulation is in the middle of progress. It differs from the input method when restarting the simulation. When the simulation is stopped, the description means of the simulation model must be converted from the internal description means to the model description means.

However, the state of the simulation model is always distorted by the conversion of the description means. In addition, once the simulation starts, the amount of internal data is huge compared to the initial input data.
The model description means aims to be able to easily input the initial conditions, but is not suitable for describing in enormous amounts of data in detail.

This is because the user cannot specify the initial conditions of the simulation model in detail at the start of the simulation. The conventional discrete event simulation device is designed in this way
If the simulation is to obtain the steady-state result of a system with stochastic events, it is not important to set the initial state of the simulation model in detail. This is because if the simulation is performed for a sufficiently long period to obtain the steady state of the model, the effect of the initial state will be small.

However, it is important to be able to input the initial state of the simulation model in detail when performing a simulation such as a simulation of a system without a stochastic event or a simulation of past cases.

Further, when the simulation is interrupted and restarted, if the state of the simulation model is stored as it is as the internal description means, the state can be stored without distortion without conversion. However, at that time, it must also have an input means for reading the simulation model described by the internal description means. Therefore, it has two input means and is redundant. Further, since the internal description means is a method for a computer, it is difficult for the user to describe it in detail when the user wants to give the initial state of the simulation model in detail.

According to the present invention, it is possible to suspend and restart the simulation, which has been difficult in the past, in the same manner as when the simulation is continued, and the user can give the initial state of the simulation model in detail when starting the simulation. It is an object of the present invention to provide a discrete event simulation device that can be used.

[0015]

In order to achieve the above object, the present invention provides a state input means for reading the state of a simulation model stored in an external storage device at the start of simulation according to a user's description format, and a state input means. A database device that stores data representing the state of a simulation model read by the input means in accordance with its storage format, manages the data, and has a function of updating management information and a function of managing search information; Status reading means for reading necessary information about the simulation model from the database device during driving,
Event driving means for selecting an appropriate event routine corresponding to the earliest event in the event list read from the database device using the status reading means, and executing the selected event routine, and execution by the event driving means When the event is captured, a command is given to the database device to update the description of the state of the simulation model by the management information update function and the search information management function, and at the end of the simulation or during the simulation execution. When an interruption event is determined, a state output means for reading all data or a part of data relating to the simulation model from the database device and saving the data in the external storage device is provided.

[0016]

In the discrete event simulation apparatus having such a configuration, the simulation model described in the user-specified description format from the external storage device to the database device using the state input means at the start of the simulation follows the storage format. Since it is stored, the description means for holding the state of the simulation model inside the database device is in the format itself defined by the user.

When the event list is fetched from the database device using the status reading means, the event driving means selects the discrete event that occurs earliest, an appropriate event routine is selected, and the state rewriting means selects the event routine. The description of the state of the simulation model is rewritten by the function of updating the management information of the database device and the function of managing the search information in accordance with

Further, when it is determined that there is an interruption event during the execution of the simulation, the state output means outputs all the states of the simulation model in the form of a database device and saves them in an external storage device. By inputting the state of the simulation model by the state input means, the simulation can be restarted in the same manner as continuous simulation. In this case, since the simulation model description method itself defined by the user is handled inside the data device, the user can input the initial state of the simulation model as easily and in detail as when data is supplied to the database device.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a basic configuration example of a discrete event simulation device according to the present invention. In FIG.
The database device 1 takes in a file saved in, for example, an external storage device (disk) of a computer (not shown) and stores it as a state of a simulation model. The description of the simulation model is in the format of this discrete event simulation device. The storage format shall conform to the format of the database device. In addition, the state of the simulation model stored in the database device 1 also includes an event list representing future events and statistical information of the simulation result. Details of the database device 1 will be described later.

The state reading means 2 retrieves necessary information about the simulation model from the database device 1. The state rewriting means 3 changes the data of the simulation model described in the database device 1,
The state of the simulation model is rewritten when searching or registering.

The event driving means 4 reads the event list from the database device 1 using the status reading means 2, selects an appropriate event routine 7 corresponding to the earliest event in the event list, and executes it. At the same time, the state rewriting means 3 is used to delete the event from the event list.
This is called event driving.

The state input means 5 and the state output means 6 are
When the event driven by the event driving means 4 is input / output to / from a simulation model of an external storage device of a computer (not shown), the input / output of the data is performed. The state input means 5 reads the description data of the simulation model from the external storage device according to the description format of the user at the start of the simulation or during the execution of the simulation, and stores it in the database device 1. The state output means 6 reads out all or part of the data regarding the simulation model from the database device 1 at the end of the simulation or during the execution of the simulation and outputs the information of the simulation model to the external storage device for storage.

Here, an outline of a basic configuration example of the database device 1 will be described with reference to FIG. As shown in FIG. 2, the database apparatus 1 individually and selectively registers and deletes a plurality of lines with respect to a plurality of tables that meet a plurality of conditions, using a sequence of a plurality of words as a line. To search for lines based on content,
Input means 11, storage means 12, table designation means 13, management means 14, registration means 15, sort means 16, search means 1
7, deletion means 18, and output means 19.

The input means 11 has a function of inputting a sequence of a plurality of words as a line, a previously registered line is designated by word contents or a position of the line, and a search command, a deletion command or a change command is input. Have the function to

The storage means 12 has a function of storing a plurality of table information including sort rules set in each table, line information registered in each table and sort order information thereof. The table designating means 13 has a preset constant registration condition indicating the correspondence between the lines and the table, and responds to the input of the line by the input means 11 in response to the content of the word of the input line and the registration condition. Based on the function of designating a plurality of tables for registering the line, and in response to the input of the search command, the deletion command, or the modification command of the registered line by the input means 11, the contents of the word of the specified line and It has a function of designating a plurality of tables in which the line is registered based on registration conditions.

The management means 14 manages a plurality of table information stored in the storage means 12 and provides a plurality of table information designated by the table designation means 13, and registration by the registration means 15 and the sorting means 16. It has a function of updating the management information by the information and the deletion information by the deletion means 18, and a function of managing the search information by the search means 17.

Generally, the table creating means 20 is provided in the managing means 14.
The table creating means 20 has a function of creating a new table that matches the specified table when the table specified by the table specifying means 13 does not exist in the storage means.

The registering means 15 receives a plurality of table information designated by the table designating means 13 from the managing means 14 in response to the input of the line by the inputting means 11, and the line entered by the inputting means 11 in each table. Has the function of registering each.

The sorting means 16 has a function of sorting the lines registered in the plurality of tables by the registration means 15 on the table based on the contents of the word at the position specified by the sorting rule set in each table. Have.

The search means 17 responds to the input of the search command, the delete command, or the change command of the registered line from the input means 11 from the management means 14 with the plurality of table information designated by the table designating means 13. It has a function of retrieving the registered lines designated by the input means 11 based on the order received and sorted by the sort means 16 on each table.

The deleting means 18 receives the plurality of table information searched by the searching means 17 in response to the input of the delete command or the change command of the registered line by the input means 11 and searches each table. It has a function to delete the line.

The output means 19 has a function of outputting the management information by the management means 14. Next, the processing functions of the respective means shown in FIG. 1 and the related processing functions of the respective means of the database apparatus 1 shown in FIG. 2 when starting the simulation will be described.

To start the simulation, it is necessary to first read the state of the simulation model from a file stored in an external storage device of a computer (not shown) and store it in the database device 1. By means 5.

When reading the designated file, the state input means 5 is operated by the means of the database device 1 of FIG. 2 as follows. (1) The input means 11 inputs a line in a file saved in an external storage device. (2) The line is registered by the registration means 15. (3) The sorting means 16 sorts according to the registration conditions and stores it. (4) The management means 14 updates the table and line management information.

Discrete events are also included in the state description of the simulation model. The event driving means 4 drives the earliest event in this event list. The event driving means 4 functions as follows. (1) The data of the event that occurs earliest is read from the database device 1 by the state reading means 2. (2) The state rewriting means 3 deletes the data from the database device 1. (3) The event routine 7 corresponding to the event is driven.

Here, in (1), the status reading means 2
From the means of the database device 1 is as follows. (1-1) The table designating unit 13 designates a table corresponding to the event list. (1-2) The table management information is obtained by the management means 14. (1-3) The designated table is retrieved by the retrieval means 17. (1-4) The search means 17 searches for the line of the event having the earliest occurrence time. (1-5) The data of the event that occurs earliest is returned by the output means 19.

Further, in (2), the state rewriting means 3 becomes as follows by means of the database device 7. (2-1) The deletion means 18 deletes the line of the earliest event that has been searched. (2-2) The management unit 14 updates the table and line management information.

In general, the status reading means 2 functions when the event driving means 4 and the event routine 7 need some data, and then the event driving means 4 and the event routine 7 specify the required data. Then, the state reading means 2 is activated. (1) The table specifying means 13 manages a table of specified data. (2) The table management information is obtained by the management unit 14. (3) The search means 17 searches for a table or a line. (4) The output means 19 returns the data.

In general, the state rewriting means 3 is a means for rewriting such as changing, registering or deleting the table or line of the database device 1. It is activated primarily by the event routine 7, but is also activated by the event driven means 12. That is, the event routine 7 represents how the simulation model changes when an event corresponding to the event routine occurs. The event routine 7 is a procedure for changing the state description of the simulation model in the database device 1. The state rewriting means 3 functions by the means of the database device 1 as follows. (1) The table specifying means 13 specifies a table relating to the data to be rewritten. (2) The management means 14 obtains a table and line management information.
When registering, create a table if it does not exist. (3) The search means 17 searches for tables and lines. (4) Register, delete, and change. (5) The management means 14 updates the table and line management information.

The input and output of the state description of the simulation model can be performed even while the simulation is being executed. In this case, an event routine for inputting and outputting may be prepared. For example, as an extreme example, a simulation model is given as an input at the start of simulation,
The content may be only the event list. However, as the earliest event in the event list, prepare an event that inputs a file that has all the information related to simulation. Then, at the moment the simulation started,
Although it is a simulation model with only an event list,
At the next moment, all the information of the simulation model is input to the discrete event simulation device.

When it is desired to output a part or all of the state description of the simulation model from the discrete event simulation device, the state output means 6 is activated. In this case, output format (file name, file format)
May be described in the simulation model. All data (conditions, etc.) involved in performing a simulation with this discrete event simulation device are regarded as the state description of the simulation model. This state output means 6 functions as follows. (1) If the output format is designated by the status reading means 5, it is read. (2) A table or line of data to be output is designated and searched, and the data is returned by the output means 19. (3) The returned data is output to the external storage device of the computer (not shown) according to the designated output format. In this case, it may be output to the screen display device.

Next, the operation of the discrete event simulation apparatus having the above-described configuration will be described. Here, how the database apparatus described above specifically realizes the simulation will be described in detail.

A specific example of the discrete event simulation used for the explanation is shown in FIG. Simulates one queue, one window. For example, it corresponds to a model of a small post office with only one window. The part corresponding to the inside of the post office is called a queue, and the queue consists of a window and a queue.

First, the queue will be described. The movements of customers in this are as follows. Customers arrive from outside the queue. If there is no customer receiving the service at the window, the service will start immediately. If there is already a customer at the window, wait until the window is open. If there are multiple customers waiting, wait in line in the order in which they arrived in the queue. When the customer at the counter has finished the service, the customer leaves the queue. If there is a customer waiting in line at that time, the customer at the head of the line enters the window and begins to receive service. Only one customer can serve at the counter at a time.

As shown in FIG. 3, the range of the simulation model is from before the customer arrives to when the customer leaves after the service ends. The state of the model is represented by the state of each customer and the information about each customer.

FIG. 4 shows the state of the customer, and there are four types of states. The four types are: COMING IN before the customer arrives in the queue, IN LINE when the customer is waiting in line, BEING SERVED when the customer is receiving the service at the counter, and from the counter when the service ends. It is GONE AWAY in the state of moving out. FIG. 5 is a drawing drawn corresponding to FIG.

The number of events that change the state of the simulation model to perform the simulation depends on the concept of the model. Here, the simulation is performed with two events as shown in FIG. FIG. 6 shows two events (arrival event and leaving event).

Arrival event AR causes a customer in the state of COMING IN to arrive in the queue. If the window is free, put the customer in the window and make it BEING SERVED. If there is a customer in service at the counter, wait. If there are other customers waiting, wait in line in the order in which they arrived in the queue.

The eviction event LV evicts a customer who is BEING SERVED from the queue and makes it GONE AWAY. Then, the window will be open, so if you are waiting for customers at the line, put the first customer in the line at the window. The customer status from IN LINE to BEING SERV
Change to ED.

When a customer enters the window for both arrival and departure events, the event that the customer leaves is registered in the event list. Here, the handling of data in the database device in this embodiment will be described with reference to FIG. The database device manages and handles many tables described below. The table is a collection of lines that meet preset registration conditions and is sorted by certain conditions. Lines are used as data units in the database device. One line is an ordered pair of three words. A word is 1. an integer pair, 2. a string integer pair, 3. a string pair, or 4. a floating point.

FIG. 8 shows an example of one table. This is a table in which lines are collected under the registration condition that the central word is TRACE TRACE, and the lines are sorted using the left word as the sort key. The table consists of 5 lines, each line consisting of an ordered pair of 3 words. FIG. 7 shows examples of [integer], [integer], [character string], [integer], [character string], and [character string] as examples of words. FIG. 9 shows an example of a floating point number word.

This database device manages and handles a large number of tables as shown in FIG. 8. In this case, the registration conditions for associating the line, which is a data unit, with the table to be registered are set in advance so that the line contents are automatically The table to be registered is specified, the management of the table and the line is easy, and the data can be flexibly and efficiently managed even if the usage that was not expected at the time of starting the use of the database occurs.

As the state of the simulation model, the state of each customer, statistical information, and a list of events that will occur in the future are described and simulation is performed. For statistical information, we will take tracking information of each customer and average staying time in the queue. This is a record of when each guest came and went to the queue and the average stay time.

FIG. 10 shows a description example of the event list. The event occurrence time sec 800 is in the left word,
The word FUTURE EVENT in the middle indicates that this line represents an event that will occur in the future, and the word ARO on the right indicates that the event that occurred is a customer arrival. AR here
The right O has no meaning.

FIG. 11 shows two types of lines for describing a customer, which is a line showing the status of the customer and the tracking information of the customer. In 1., it represents customer 1, the current state is waiting in line, and it has 400 service hours. 2. indicates the tracking information of the customer 2. The central word TRACE TRACE indicates that this line represents tracking information. Right word
At 840 1500, record the time of arrival and departure of the queue. Negative numbers are recorded when they have not arrived yet or when they have not left.

FIG. 9 shows a line representing the average stay time. The central word MEAN RESPONSE indicates that this line represents average dwell time. The integer 2 on the right of the left word is the number of customers who have left the window (service has ended). The left integer 1060 in the left word is the sum of the queued time of those guests. Right word floating point number 530.0
Represents the average staying time of customers (1060/2).

The initial state of the simulation model is represented according to the description rules described so far. The arrival time and service time of each customer are shown in FIG. The initial state given to the database device is shown in FIG. An event list is created based on the arrival time of each customer. The initial state of each customer is COMING
It is IN and the service time is written on the same line. The line of tracking information for each customer has no result at the start of the simulation, so enter a negative number. The number on the line representing the average time spent in the queue is set to zero.

Although not in the present embodiment, if the simulation has priorities for input / output and customers, these may be described as lines in the database. FIG. 14 shows the movement of each customer when this simulation model represents how it changes each time an event occurs along the flow of time.

Next, the discrete event simulation apparatus is shown in FIG.
The operation when an initial state as shown in 3 is given will be described. In FIG. 1, when the state input means 5 is activated by the start of the simulation, the initial state shown in FIG. 13 is read from the external storage device of the computer (not shown) and the data is written to the database device 1 that manages the event list. Next, the state reading means 2 reads all or part of the states of the simulation model from the database device 1. In this case, if all is specified, all state data is read, and a search is performed by specifying the word and the position of the word (left, center, right), or by specifying from the earliest sort order among a plurality of words. .

The status reading means 2 reads the corresponding line by such a search. In this case, it is possible to search for a line using the line search means 17 of the database device 1 shown in FIG.

The state rewriting means 3 is made to function when changing the state of the simulation model, and the database device 1
Change the content of some or all of the specified lines of the line, delete the specified line, or add a new 3
Register a new line by combining two words. In this case, the line registration means 15, the deletion means 18, and the change means of the database device 1 are used to change the contents of the line and rewrite the state of the simulation model.

Here, consider a case where the past time 1200 is written in the tracking information of the customer 1. The line representing this is Customer 1 TR
ACE TRACE 800 -1. Change the word 800-1 on the right to 800 1200. Also, the line registration means is used when state rewriting such as adding a new event list sec 1700 FUTURE EVENT LV O.

Next, regarding the function of the event driving means 4, FIG.
This will be described with reference to the flowchart shown in FIG. First,
The word in the center of the event list is FU by the status reading means 2.
You get by searching for the line that is a TURE EVENT. Then, the event with the earliest time in the event list is selected and the event is driven. In the initial state of the simulation model shown in Fig. 13, the arrival event AR is at time 800.
The event routine 7 corresponding to AR is executed. 16 and 17 show the flow of the event routine of the arrival event and the event routine of the past event. Rewriting by the event routine is added to the state of the simulation model, and the line representing the driven event (initial state or AR) is deleted from the event list.

Here, in order to explain the routine of the arrival event, an example of driving the earliest time event and the arrival event in the initial state will be described. First, by the state reading means 2,
Search for the line whose center word is COMING IN and select the line with the smallest customer number. here,
customer 1 COMING IN serv 400. In this case, the customer 1 is the arriving customer. Next, to find out the presence of customers in service, search the line where the central word is BEING SERVED. As a result of the search, if there is a customer who is in service, the word in the center of the line of the customer to be arrived is changed to IN LINE. In this initial state, there are no customers in service. In this case, BEING SE is the word in the center of the line of customer 1.
Change to RVED. Customer 1 enters the window, so the time to leave the window is decided. Time to move out = time entered + service time, that is, move out at time 1200 (= 800 + 400). A line indicating that an evacuation event will occur at time 1200 is registered in the event list. Further, the line recording the tracking information of the customer 1 is searched. Left word is customer1, middle word is TRACE
Find the line that is TRACE. Change word -1 -1 to the right of that line to 800 -1.

When the driving of the arrival event at time 800 is completed, the state of the simulation model becomes as shown in FIG.
Next, the operation of the discrete event simulation device when the simulation is interrupted will be described. It is assumed that the simulation is interrupted immediately after the customer 1's exit event at time 1200 added above is driven. In this case, the simulation can be interrupted by registering an event for interrupting the simulation immediately after the leaving event at time 1200.

The state output means 6 of FIG. 1 outputs the current state of the simulation model from the database device 1 to an external storage device of a computer (not shown) and holds it. FIG. 18 shows the state immediately after time 1200. In this case, the event list, the state of each customer, the tracking information of each customer, and the average stay time are output as the state of the simulation model. Also,
When outputting, all the states of the simulation model are output in that format as recorded in the database device 1. Therefore, when restarting the simulation, the state input means 5 simply inputs this to the discrete event simulation device. Is.

When one simulation event is driven from the state shown in FIG. 19, the results shown in FIG. 20 are obtained, and it can be seen that the simulation can be continued even if the simulation is interrupted. To drive one simulation drive,
9 is read and the state of the simulation model is written in the database device 1. The discrete event simulation device starts the simulation. That is, the event driving means 4 is executed. Here again, the event with the earliest time is selected and the event routine is executed. Then, the event driven after the execution of the routine is deleted from the event list.

Next, the event routine of the past event will be described by executing the past event at time 1500 in the state of FIG. First, the state reading means 2 causes the central word to be BEIN.
Search for lines that are G SERVED. In the state of Fig. 20, cu
It is a stomer 2 BEING SERVED serv 300. The word in the center of the line is changed to GONE AWAY by the state rewriting means 6. Search for the customer's tracking information line using the number of the customer who left. Left word is customer 2, center is TRACE
Find the line that is TRACE and change the integer to the right of the word to the right of that line to the current time 1500. 840 -1 to 840 1500
Change to. Next, the state reading means searches for a line representing the average stay time with the central word MEAN RESPONSE, and the state rewriting means 6 changes the left integer (total stay time) and the right integer (the number of leaving guests) of the left word. . Customer 2 here
Arrived at time 840 and left at time 1500 for a stay of 66
It is 0 (= 1500-840). The word to the left of it is 1060 2 (400 + 66
01 + 1). The word that represents the average time on the right is 530.0 (= 1
060/2). If there are customers waiting in line to wait for the window to open, put the first customer in the row into the window. The state reading means 2 searches for a line having the word IN LINE in the center. If the line does not exist, the past event routine ends.
In the case of FIG. 19, there are two corresponding lines. Select the line with the lowest number and IN L the word in the center of that line.
Change from INE to BEING SERVED. Here, the line of the customer 3 is selected and the line is changed. As the customer enters the service, the time to leave the window is decided. Time to move out = time entered + service time (here, move out at time 1200 (= 800 + 400). At time 1200, a line indicating that a move-out event occurs at move-out time (here time 1200) is added to the event list. register.

In this case, the simulation ends when there are no more events in the case list. FIG. 21 shows the state of the simulation model that has driven all the event lists.

It is very easy to modify the simulation model in which a new customer is added to FIG. 19 interrupted immediately after the time 1200. For example, when the customer 6 arrives at the time 3000 and has the service time 500, if the simulation is restarted from the state of FIG. 23 in addition to the data shown in FIG. 22, the simulation with the customer 6 can be performed.

In this way, as is apparent from the above embodiment, the user gives all states of the simulation model in the description format of the simulation model defined by the user according to the format of the database device 1.
It can be stored in the database device 1 as it is and the simulation can be executed.

Further, since the database device 1 automatically designates the correspondence between the line and the table according to the contents of the line to be registered, the data can be output flexibly even if the state description data which does not exist at the start of the simulation appears.

Further, since the state of the simulation model is output and held in the form of the database device 1 when the simulation is interrupted, the simulation can be restarted by giving the output again as an input.

In the above embodiment, the database device 1
Although the data exchange with the external storage device of the electronic computer has been described, the external storage device may be, for example, a floppy disk, a hard disk, a RAM memory, a punch card or the like which can input / output data. Any number of storage media may be used.

[0075]

As described above, in the present invention,
Provides a discrete event simulation device that can interrupt and restart the simulation, which has been difficult in the past, as if the simulation was continued, and that allows the user to give the initial state of the simulation model in detail when starting the simulation. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a discrete event simulation device according to the present invention.

FIG. 2 is a conceptual diagram for explaining an internal configuration of a database device used in the embodiment.

FIG. 3 is a model diagram showing an example of a case where a simulation is performed by the apparatus of the embodiment.

FIG. 4 is a view for explaining the entire state of customers in the same example.

5 is a diagram in which FIG. 2 corresponds to the four states described in FIG.

FIG. 6 is an explanatory diagram of two events driven in simulating the model of the same example.

FIG. 7 is a diagram for explaining the configuration of a database device used in the same example.

8 is a diagram showing an example of FIG. 7. FIG.

FIG. 9 is a diagram for explaining a line for recording an average stay time.

FIG. 10 is a diagram for explaining a line representing an event that will occur in the future.

FIG. 11 is a diagram showing a description example of a line regarding one customer.

FIG. 12 is a diagram showing the arrival time and service time of each customer.

FIG. 13 is a diagram showing an initial state of a simulation model in the same example.

FIG. 14 is a diagram showing, for each event, the behavior from the beginning to the end of the simulation model in the same example.

FIG. 15 is a flowchart showing an event driven procedure of the discrete event simulation device according to the present invention.

FIG. 16 is a flowchart showing an event routine of an arrival event.

FIG. 17 is a flow chart showing an event routine of a leaving event.

18 is a diagram showing a state of the simulation model immediately after driving the first event in the initial state shown in FIG.

FIG. 19 is a diagram showing an output state of the simulation model, which is interrupted immediately after driving of the leaving event at time 1200 and stopped.

FIG. 20 is a diagram showing a state immediately after driving an evacuation event at time 1500, in which the simulation is expanded from the state of the simulation model.

FIG. 21 is a diagram showing a state of the simulation model when the simulation of this example is finished.

22 is a diagram showing necessary data when making a change such as adding a sixth customer to FIG. 9 suspended at time 1200. FIG.

23 is a state diagram of a simulation model when a sixth customer is added to FIG.

[Explanation of symbols]

1 ... Database device, 2 ... Status reading device, 3 ...
State rewriting device, 4 ... Event drive means, 5 ... State input means, 6 ... State output means, 7 ... Event routine, 11 ...
... input means, 12 ... storing means, 13 ... table specifying means,
14 ... Management means, 15 ... Registration means, 16 ... Sort means, 17 ... Search means, 18 ... Delete means, 19 ...
Output means, 20 ... Table preparation means.

Claims (2)

[Claims] 1. A state input means for reading the state of a simulation model stored in an external storage device at the start of simulation in accordance with a user's description format, and data representing the state of the simulation model read by the state input means. A database device that stores data according to a storage format and manages the data, and also has a function of updating management information and a function of managing search information, and a state in which necessary information about a simulation model is read from the database device when an event is driven. Reading means, event driving means for selecting and executing an appropriate event routine corresponding to the earliest event in the event list read from the database device using the status reading means, and this event When the event executed by the driving means is captured, the data State rewriting means for rewriting the description of the state of the simulation model by the management information update function and the search information management function by giving a command to the base device, and the database when the interruption event is determined at the end of the simulation or during the simulation execution A discrete event simulation device, comprising: a state output means for reading out all or part of data relating to a simulation model from the device and storing the data in the external storage device. 2. The database device selectively and individually registers and deletes a plurality of lines with respect to a plurality of tables that meet a plurality of conditions by using an ordered sequence of a plurality of words as a line, and based on the content of the word. 2. The discrete event simulation device according to claim 1, wherein the line is searched for by a line.