Discrete-Event System Objects

Implement a discrete-event System object™ using MATLAB Discrete-Event System block

You can extend the existing functionality of SimEvents^® by authoring new blocks to model behaviors that are not provided with a SimEvents built-in solution. To create custom functionality in SimEvents models, you can use the MATLAB Discrete-Event System block that allows you to implement a discrete-event System object written in MATLAB^® language.

To implement a custom discrete-event System object, inherit matlab.DiscreteEventSystem class. Link the System object to a SimEvents model by using a MATLAB Discrete-Event System block. The linked MATLAB Discrete-Event System block exhibits the desired custom behavior during simulation.

Blocks

MATLAB Discrete-Event System

MATLAB discrete-event system

Classes

matlab.DiscreteEventSystem Base class for discrete-event system objects

Methods

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Events

`eventAcquireResource`	Create a resource acquisition event
`eventDestroy`	Create entity destroy event
`eventForward`	Create entity forward event
`eventGenerate`	Create entity generate event
`eventIterate`	Create entity iterate event
`eventReleaseResource`	Create an event to release previously acquired resources
`eventReleaseAllResources`	Create an event to release all resources acquired by an entity
`eventTestEntry`	Create an event to indicate that the acceptance policy for the storage has changed and the storage retests arriving entities
`eventTimer`	Create entity timer event
`initEventArray`	Initialize event array
`initResourceArray`	Initialize a resource specification array

Event Actions

`blocked`	Event action when entity forward fails
`destroy`	Event action upon entity destruction
`entry`	Event action when entity enters storage element
`exit`	Event action before entity exit from storage
`generate`	Event action upon entity creation
`iterate`	Event action when entity iterates
`modified`	Event action upon entity modification by the Entity Find block
`resourceAcquired`	Event action upon successful resource acquisition
`resourceReleased`	Event action upon successful resource release
`testEntry`	Event action to accept or refuse entity
`timer`	Event action when timer completes

Cancelling Events

`cancelAcquireResource`	Cancel previously scheduled resource acquisition event
`cancelDestroy`	Cancel previously scheduled entity destroy event
`cancelForward`	Cancel previously scheduled forward events
`cancelGenerate`	Cancel previously scheduled entity generation event
`cancelIterate`	Cancel previously scheduled iterate event
`cancelTimer`	Cancel previously scheduled timer event

Storage, Entity, and Resource Specification

`entityType`	Define entity type
`getEntityPortsImpl`	Define input ports and output ports of discrete-event system
`getEntityStorageImpl`	Define entity storage elements of discrete-event system
`getEntityTypesImpl`	Define entity types of discrete-event system
`getResourceNamesImpl`	Define resource pools from which to acquire resources
`queueFIFO`	Define first-in first-out (FIFO) queue storage
`queueLIFO`	Define last-in last-out (LIFO) queue storage
`queuePriority`	Define priority queue storage
`queueSysPriority`	Define system priority queue storage
`resourceSpecification`	Create specifications for a resource acquisition or a resource release event
`resourceType`	Specify an entity type and the name of the resources to be acquired by the specified entity
`setupEvents`	Initialize entity generation events

Topics

SimEvents Common Design Patterns

The SimEvents library provides design patterns that you can refer to while modeling.

Create Custom Blocks Using MATLAB Discrete-Event System Block

Author discrete-event System object by defining entity types, ports, storage, and events.

STEP 1: Delay Entities with a Custom Entity Storage Block
STEP 2: Create a Custom Entity Storage Block with Iteration Event
STEP 3: Custom Entity Storage Block with Multiple Timer Events
STEP 4: Custom Entity Generator Block with Signal Input and Signal Output
STEP 5: Build a Custom Block with Multiple Storages
STEP 6: Create a Custom Resource Acquirer Block

Create a Discrete-Event System Object

Use the matlab.DiscreteEventSystem class to implement a discrete-event System object.

Generate Code for MATLAB Discrete-Event System Blocks

Configure MATLAB Discrete-Event System block.

Customize Discrete-Event System Behavior Using Events and Event Actions

Define and work with events in custom discrete-event systems.

Call Simulink Function from a MATLAB Discrete-Event System Block

Call Simulink^® function from a MATLAB Discrete-Event System Block.

Resource Scheduling Using MATLAB Discrete-Event System and Data Store Memory Blocks

This example shows how to model resource scheduling using data exchange between the MATLAB Discrete-Event System block and the Data Store Memory block.

Featured Examples

Server with Pause/Continue

Use a MATLAB Discrete Event System block to model a single server that can pause service. The input port IN receives entities to be served. Additionally, the system may receive sporadic pause commands on port PauseCmd. If the message received on the PauseCmd port carries data=1, the system pauses. The system reschedules service for the current entity when it receives a continue message on this port, i.e. a message that carries data=0.

Open Script

Selection Server - Select Specific Entities from Server

Use the MATLAB Discrete Event System block to write a custom N-Server from which specific entities can be selected using a key lookup. Passengers enter from the IN port of the block and are stored in the block until a message arrives at the KEY port carrying a lookup key. Upon receiving this message, the system schedules an "Iterate" event during which it can visit every entity stored in it and output the one that matches the key.