SimEvents
®
Release Notes
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®
SimEvents
© COPYRIGHT 2005–20 10 by The MathWorks, Inc.
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Release Notes
Summary by Version ............................... 1
Contents
Version 3.1 (R2010a) SimEvents Software
Version 3.0 (R2009b) SimEvents Software
Version 2.4 (R2009a) SimEvents Software
Version 2.3 (R2008b) SimEvents Software
Version 2.2 (R2008a) SimEvents Software
Version 2.1 (R2007b) SimEvents Software
Version 2.0 (R2007a) SimEvents Software
Version 1.2 (R2006b) SimEvents Software
Version 1.1 (R2006a) SimEvents Software
Version 1.0 (R14SP3+) SimEvents Software
............ 4
............ 11
............ 13
............ 18
............ 20
............ 23
............ 34
............ 43
............ 51
.......... 53
Compatibility Sum mary for SimEvents Software
..... 55
iii
iv Contents
SummarybyVersion
This table provides quick access to what’s new in each version. For
clarification, see “Using Release Notes” on page 1 .
SimEvents®Release Notes
Version
(Release)
Latest Versi
V3.1 (R2010a
V3.0 (R2009b)
V2.4 (R2009a)
V2.3 (R2
V2.2 (R2008a)
V2.1 (R2007b)
V2.0 (
V1.2 (R2006b)
008b)
R2007a)
New Features
and Changes
on
Yes
)
Details
Yes
Details
Yes
Details
Yes
Details
Yes
Details
Yes
Detai
Yes
Details
Yes
Details
Version
Compatibilit
Consideratio
Yes
Summary
No Bug Reports
Yes
Summary
No Bug Reports
No Bug Reports
Yes
ls
Summa
Yes
Summary
Yes
Summary
ry
y
ns
Fixed Bugs
and Known
Problems
Bug Reports
Includes fix
Includes fixes
Bug Repor
Includes
Includes fixes
Includes fixes
Bug Rep
Inclu
Bug Reports
Includes fixes
Bug Reports
Includes fixes
es
ts
fixes
orts
des fixes
Related
Documentation
at Web Site
Printable R elease
Notes: PDF
Current product
documentation
No
No
No
No
No
No
No
V1.1 (R2006a)
.0 (R14SP3+)
V1
Reports
Yes
ails
Det
Yes
Details
sing Release Notes
U
se release notes when upgrading to a newer version to learn about:
U
Yes
mary
Sum
Not applicable
Bug
ludes fixes
Inc
Bug Reports No
No
1
SimEvents®Release Notes
• New features
• Changes
• Potential impact on your existing files and practices
Review the release notes for other MathWorks™ products required for this
product (for example, MATLAB
®
or Simulink®). Determine if enhancements,
bugs, or compatibility considerations in other products impact you.
If you are upgrading from a software version other than the m ost recent one,
review the current release notes and all interim versions. For example, when
you upg rade from V1.0 to V1.2, review the release notes for V1.1 and V1.2.
What Is in the Release Notes
New Features and Changes
• New functionality
• Changes to existing functionality
Version Compatibility Con si derations
When a new feature or change introduces a reported incompatibility between
versions, the Compatibility Considerations subsection explains the
impact.
Compatibility issues reported after the product release appear under Bug
Reports at The MathWorks™ Web site. Bug fixes can sometimes result
in incompatibilities, so review the fixed bugs in Bug Reports for any
compatibility impact.
Fixed Bugs and Known Problems
The MathWorks offers a user-searchable Bug Reports database so you can
view Bug Reports. The development team updates this database at release
time and as more information becomes available. Bug Reports include
provisions for any known workarounds or file replacem ents. Information is
available for bugs existing in or fixed in Release 14SP2 or later. Information
is not avail able for all bugs in earlier releases.
2
Access Bug Reports using y our MathWorks Account.
SummarybyVersion
3
SimEvents®Release Notes
Version 3.1 (R2010a) SimEvents Software
This table summarizes what’s new in Version 3.1 (R2010a):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Yes
Summary
New features and changes introduced in this version are
• “Block-Based Breakpoints in Debugger” on page 4
• “Block Operations Information in Debugger” on page 5
• “Changes in Behavior of Pending Entity Signals” on page 5
• “Renamin g of Parameter to Enable Pending Entity Signal” on page 9
• “Expanded Options for Opening Release Gate” on page 9
• “Blocks in Attributes Library Must Get or Set at Least One Attribute”
on page 10
• “Parameters and Parameter Values B eing Removed” on page 10
Fixed Bugs an d
Known Problems
Bug Reports
Includes fixes
Related
Documentation at
Web Site
Printable Release
Notes: PDF
Current product
documentation
Block-Based Breakpoints in Debugger
With the SimEvents®debugger, you can investigate the behavior of particular
blocks using block-based breakpoints. After you establish a breakpoint on
a block, the debugger suspends the simulation when that block is about to
perform certain operations. For details, see these resources:
•
sedb.blkbreak function reference page
• “Defining a Breakpoint”
• “Using Breakpoints During Debugging”
• “Block Operations Relevant for Block Breakpoints”
4
Version 3.1 (R2010a) SimEvents®Software
Block Operations Information in Debugger
These blocks now include their operations in the simulation log:
• Discrete Event Signal to Workspace
• Instantaneous Event Counting Scope
• Signal Scope
• X-Y Signal Scope
These blocks now appear in the output of the
valid as inputs to the
• Discrete Event Signal to Workspace
• Discrete Event Subsystem
• Instantaneous Event Counting Scope
The
sedb.blklist function sorts its Command W indow output and cell array
output by block names instead of by block identifiers.
sedb.blkinfo function:
sedb.blklist function and are
Compatibility Considerations
If you have code that manipulates or indexes into the output cell array from
sedb.blklist,youmightneedtoupdatethecodetoreflectnewrowsora
different sequence of rows.
Changes in Behavior of Pending Entity Signals
The blocks in the following table have an optional pe or #pe signal output
port. The signals at these ports provide information about pending entities
in the block. The port behaviors are now simpler and more consistent across
the various blocks.
Block
Has
Optional pe
Port
Has
Optional
#pe Port
Event-Based Entity Generator
Infinite Server
Yes No
Yes Yes
5
SimEvents®Release Notes
Block
N-Server
Output Switch
Single Server
Time-Based Entity Generator
In V3.1 (R2010a), a pending entity is an entity that has tried and failed to
depart from the block in which the entity resides.
When a block produces a pe output signal, the signal has an update (that is, a
sample time hit) whenever there is a change in the set of pending entities that
the block stores. The signal value is:
• 1, if the block stores one or more pending entities
• 0, if the block does not store any pending entities
When a block produces a #pe output signal, the signal has an update
whenever there is a change in the set of pending entities that the block stores.
The signal value is the number of pending entities that the block stores.
Has
Optional pe
Port
Yes Yes
Yes No
Yes No
Yes No
Has
Optional
#pe Port
Compatibility Considerations
If your models use the pe or #pe signal to control simulation behavior, perform
computations, or return results, your m odels might behave differently. The
table summarizes the behavioral changes most likely to affect your models.
6
Version 3.1 (R2010a) SimEvents®Software
Affected Blocks
• Event-Based Entity
Generator
• Infinite Server
• N-Server
• Output Switch
• Single Server
• Time-Based Entity
Generator
Change in Behavior
The pe signal does not have a sample time hit to reflect that an
entity departs the first time it tries to depart. Such an entity is not
a p ending entity because it does no t fail to depart.
Thesameinformationistruefor#pe in blocks that offer this port.
Example
In V3.1 (R2010a), the next model produces a plot containing no
points because no entity fails to depart from the server.
In V3.0 (R2009b), the same model produces a plot that shows
sample time hits in the pe signal when entities depart.
• Event-Based Entity
Generator
• Infinite Server
• N-Server
When pe reflects the departure or other removal of a pending
entity, the sample time hit occurs after the pending entity is no
longer in the block. In earlier versions, when the pending entity is
the only pending entity in the block, the sample time hit occurs
when the departure or other removal is imminent. The sample time
7
SimEvents®Release Notes
Affected Blocks
• Output Switch
• Single Server
• Time-Based Entity
Generator
• Event-Based Entity
Generator
• Time-Based Entity
Generator
Change in Behavior
hit occurs at the same simulation time, but in a different sequence
compared to other simultaneous events.
Example
The model, whose fragment appears in the next figure, behaves
differently in different versions. Suppose a pending entity is in
the server when the g ate opens. In V3.1 (R2010a), the entity
advances and acquires an attribute value of 1 from the pe signal.
In earlier versions, the pe signal changes from 1 to 0 before the
entity departs. As a result, when the entity advances, it acquires
an attribute value of 0.
When you c
depart, t
In this co
there is
You see t
examin
onfigure the block to produce an error if an entity fails to
he error situation does not cause a sample time hit in pe.
nfiguration, the block cannot store any pending entities, so
nostorageactiontocauseasampletimehitinpe.
he effect of this change if, after the error occurs, you
e pe in the workspace or in a plot.
8
• Infini
• N-Ser
te Server
ver
If a pen
in the b
earli
of 0 fo
Exam
In th
serv
asa
The
ent
by a
ding entity departs and one or more pending entities remain
lock, the pe signal has a single sample time hit of 1. In
er versions, in this situation, the signal has a sample time hit
llowed by a sample time hit of 1.
ple
e next model, at T = 0.5, one pending e ntity departs from the
er and one pending entity remains. In V3.1 (R2010a), pe has
mple time hit to indicate the departure of the pending entity.
value is 1 because the block still contains another pending
ity. In earlier versions, pe has a sample time hit of 0 followed
sample time hit of 1.
Version 3.1 (R2010a) SimEvents®Software
Affected Blocks
Change in Behavior
Renaming of Parameter to Enable Pending Entity Signal
Blocks that have an optional pe signal output port rename the parameter that
youusetoenabletheport. ThenameinV3.0(R2009b)isStatus of pending
entity departure or Status of pending entity. The new name in V3.1
(R2010a) is Pending entity present in block. The affected blocks are:
• Event-Based Entity Generator
• Infinite Server
• N-Server
• Output Switch
• Single Server
• Time-Based Entity Generator
Expanded Options for Opening Release Gate
You can configure the Release Gate block to open upon each sample time
hit of an input signal. Set the Open gate upon parameter to
hit from port ts
.
Sample time
9
SimEvents®Release Notes
Blocks in Attrib
One Attribute
These blocks no l
dialog box is em
• Get Attribute
• Set Attribute
Parameters a
Affected Block Affected
Parameter
• FIFO Queue
• LIFO Queue
• Priority Queue
Status of
pending entity
departure is
being r e m ov ed.
utes Library Must Get or Set at Least
onger support a configuration in which the table in the
pty:
nd Parameter Values Being Removed
What Happens
When You Use
the Parameter?
ris
the
On,
onding
loutput
nactive.
brary
the
ter is
lable.
odels
e
In legacy m
in which th
paramete
set to
corresp
pe signa
port is i
In the li
block,
parame
unavai
Use This
Instead
Number of
entities in
queue
Compatibility
Considerations
To update
legacy mod
set Statu
pending e
departu
Off.For
informa
the tech
in “Det
Whethe
Is None
The te
yield
but no
infor
sof
re to
more
tion, see
nique
ermining
raQueue
mpty”.
chnique
ssimilar,
tidentical,
mation.
els,
ntity
10
• FIFO
• LIFO
ority Queue
• Pri
Queue
Queue
Capa
have
ue.
val
city must
apositive
Warn
the v
sifyouset
alue to
0.
itive value.
Apos
rnatively,
Alte
ove the block.
rem
Remove queue
blocks whose
capacity is zero.
Version 3.0 (R2009b) SimEvents®Software
Version 3.0 (R2009b) SimEvents Software
This table summarizes what’s new in Version 3.0 (R2009b):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
No Bug Reports
Fixed Bugs an d
Known Problems
Includes fixes
Related
Documentation at
Web Site
No
SupportforBatchSimulation Using Rapid Simulation Target
SimEvents blocks support code generation using the Rapid Simulation target.
You can now perform these tasks:
• “Accelerating Discrete-Event Simulations Using Rapid Simulation”
• “Varying Parameters Between Rapid Simulation Runs”
• “Sharing Executables for Discrete-Event Simulations”
The Batch Discrete-Event Simulations Using Rapid Simulation Target demo
illustrates this feature by varying parameters between simulation runs.
This feature requires Real-Time Workshop
Simulation target.
®
software and uses the Rapid
Expanded Options for Resetting Entity Departure Counter
The Entity Departure Counter block offers you more options for resetting
the e ntity count during the simulation. The new options and corresponding
values of the Reset counter upon parameter are listed in the table.
11
SimEvents®Release Notes
Option
Reset counter upon each sample
time hit of an input signal
Reset counter upon each function
call
Value of “Reset counter upon”
Parameter
Sample time hit from port ts
Function call from port fcn
12
Version 2.4 (R2009a) SimEvents®Software
Version 2.4 (R2009a) SimEvents Software
This table summarizes what’s new in Version 2.4 (R2009a):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Yes
Summary
New features and changes introduced in this version are described here:
Fixed Bugs an d
Known Problems
Bug Reports
Includes fixes
Related
Documentation at
Web Site
No
Debugger Suppor ts Stepping, Breakpoints, and Querying
The new SimEvents debugger lets you use MATLAB functions to suspend a
simulation at each step or breakpoint, a nd query simulation state to assess
behavior. The debugger includes these functions:
help
se_getdbopts
sedb.bdelete
sedb.blkinfo
sedb.blklist
sedb.breakpoints
sedb.cont
sedb.currentop
sedb.detail
Display he lp for debugger functions
SimEvents debugger options structure
Delete breakpoints in discrete-event
simulation
Block information in discrete-event
simulation
Blocks and their identifiers in
discrete-event simulation
List breakp oints in discrete-event
simulation
Continue simulation until next breakpoint
Current operation in discrete-event
simulation
Customize debugger display in
discrete-event simulation
13
SimEvents®Release Notes
sedb.disable
sedb.enable
sedb.eninfo
sedb.evbreak
sedb.evcal
sedb.evinfo
sedb.gceb
sedb.gcebid
sedb.gcen
sedb.gcev
sedb.quit
sedb.runtoend
sedb.simtime
sedb.step
sedb.tbreak
sedebug
Disable breakpoints in discrete-event
simulation
Enable breakpoints in discrete-event
simulation
Entity information in discrete-event
simulation
Set b reakpoint for execution or cancelation
of event
Event calendar of discrete-event simulation
Event information in discrete-event
simulation
Name of currently executing block in
discrete-event simulation
Identifier of currently executing block in
discrete-event simulation
Identifier of entity currently undergoing
operation
Identifier of current event
Quit discrete-event simulation debugging
session
Run un t il end of discrete-event simulation
Current time in discrete-event simulation
Single step in discrete-event simulation
Set timed breakpoint in discrete-event
simulation
Debug discrete-event simulation
14
For more information, see these resources:
• “Overview of the SimEvents Debugger” in the SimEvents user guide
documentation
• A video tutorial on the Web, in two parts:
Version 2.4 (R2009a) SimEvents®Software
- Basic Single Stepping and Querying
- Breakpoints and Advanced Querying
• “Building a Simple Discrete-Event Model” in the SimEvents getting
started documentation (“Exploring the D/D/1 System Using the SimEvents
Debugger” section)
• “Building a Simple Hybrid Model” in the SimEvents getting started
documentation (“Confirming Event-Based Behavior Using the SimEvents
Debugger” section)
Event Logging Options Removed from Configuration
Parameters Dialog Box
The SimEvents pane of the Configuration Parameters dialog box no longer
contains event logging options. The behavior of the event logging options in
earlier versions is like the behavior of the new debugger.
Compatibility Considerations
The debugger behavior produces slightly different information, w ith a
different format, compared to the information produced by the event logging
parameters. The closest approximations to the previous behavior use the
detail and runtoend functions of the debugger.
Event Logging
Parameter Removed
Display events in
event calendar
Similar Behav ior in Debugger
1 At the MATLAB command prompt, start the
debugger on the model called
sedebug(model)
2 At the sedebug>> prom pt, configure the
debugger and run the simulation until the end:
detail none
detail('ev',1,'cal',1)
runtoend
model:
15
SimEvents®Release Notes
Event Logging
Parameter Removed
Log events when
executed
Log events when
scheduled
Log entities
advancing from
block to block
Similar Behav ior in Debugger
1 At the MATLAB command prompt, start the
debugger on the model called
sedebug(model)
2 At the sedebug>> prom pt, configure the
model:
debugger and run the simulation until the end:
detail none
detail('ev',1)
runtoend
The resulting log includes both execution
messages and scheduling messages. Execution
messages are not indented; scheduling messages
are indented.
1 At the MATLAB command prompt, start the
debugger on the model called
sedebug(model)
model:
16
2 At the sedebug>> prom pt, configure the
debugger and run the simulation until the end:
detail none
detail('en',1)
runtoend
The resulting log includes entity advancement
messages and other information. Entity
advancement messages appear indented.
To approximate the behavior that results from setting multiple parameters
for the same model, you can concatenate input arguments in the
detail(...)
Version 2.4 (R2009a) SimEvents®Software
command. For example, detail('ev',1,'en',1) is like logging event
scheduling, event execution, and entity operations.
Discrete Event Signal to Workspace Block Clarifies Timing
You can no longer place the Discrete Event Signal to Workspace block in
an atomic subsystem. The atomic subsystem executes at time instants that
conflict with the time instants at which the event-based block in the subsystem
executes. In earlier versions, placing the Discrete Event Signal to Workspace
block in an atomic subsystem can produce unexpected results. Function-Call
Subsystem and Enabled Subsystem are examples of atomic subsystems.
Compatibility Considerations
If your legacy model includes a Discrete Event Signal to Workspace block in
an atomic subsystem, update the model as follows:
1 Move the Discrete Event Signal to Workspace block o utside the atomic
subsystem.
2 Connect the block to an output signal from the subsystem.
17
SimEvents®Release Notes
Version 2.3 (R2008b) SimEvents Software
This table summarizes what’s new in Version 2.3 (R2008b):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
No Bug Reports
New features and changes introduced in this version are described here:
Fixed Bugs an d
Known Problems
Includes fixes
Related
Documentation at
Web Site
No
New Demos for Modeling Architectures and Manufacturing Processes
Version 2.3 (R2008b) introduces these new demonstrations:
Tutorial Dem o s
• Translating Events to Functions Calls
Advanced Technique Demos
• Asynchronous Execution of a Stateflow
• Building an Arrival Rate Estimator
• Interfacing with External File Formats
• Resource Allocation from Multiple Pools
®
Chart
18
Application Demos
• FIFO Buffer: Functional Model
• FIFO Buffer: Architectural Model
• Anti-Lock Braking System (ABS) Overview
• Batch Production Process
• Kanban Production System
Version 2.3 (R2008b) SimEvents®Software
AttributeNameI
GetAttributeBl
The Add button intheSetAttributeandGetAttributeblocksaddsan
attribute named
the button always adds an attribute named
AttributeN where N is a positive integer. In earlier versions,
ncrementing in Set Attribute and
ocks
Attribute1.
Change in Parameter Name of Event-Based Entity Generator Block
The Type of value change parameter in the Event-Based Entity Generator
block is now called Type of change in signal value. The new name is
consistent w ith other blocks thathaveaparameterbythatname.
19
SimEvents®Release Notes
Version 2.2 (R2008a) SimEvents Software
This table summarizes what’s new in Version 2.2 (R2008a):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
No Bug Reports
New features and changes introduced in this version are
• “Initial Value Block in Signal Management Library” on page 20
• “Discrete Event Subsystem Supports Complex and Nonscalar Values” on
page 20
• “Seed Management for Random Number Generators” on page 21
• “Configuration Parameters for Diagnostics” on page 21
• ““What’s T his?” Context-Sensitive Help Available for Simulink
Configuration Parameters Dialog” on page 21
• “New Demos” on page 22
Fixed Bugs an d
Known Problems
Includes fixes
Related
Documentation at
Web Site
No
Initial Value Block in Signal Management Library
The new Initial Value block is in a new library called Signal Management.
This block sets a signal value before the first event occurs.
20
Also, the Signal Latch block has moved from the Gates library to the new
Signal Management library.
Discrete Event Subsystem Supports Complex and Nonscalar Values
In Version 2.2 (R2008a), input signals to the Discrete Event Subsystem block
can be real or complex signals of any dimension. In earlier versions, input
signals to the block must be real scalars. For details about discrete event
subsystems, see “Working with Discrete Event Subsystem Blocks”.
Version 2.2 (R2008a) SimEvents®Software
Seed Management for Random Number Generators
New functions and diagnostics help you ensure uniqueness of seeds of random
number generators and manage sets of seeds in a series of simulation runs.
For details, see these sections:
• “Varying Simulation R esults by Managing Seeds”
•
se_getseeds function reference page
se_setseeds function reference page
•
se_randomizeseeds function reference page
•
• “Identical seeds for random number generators”
Configuration Parameters for Diagnostics
The Configuration Parameters dialog box has a new SimEvents Diagnostics
pane to advise you of race conditions and help you manage seeds of random
number generators.
For more information, see “SimEve n ts Diagnostics Pane”.
“What’s This?” Context-Sensitive Help Available for
Simulink Configuration Parameters Dialog
R2008a introduces “What’s This?” context-sensitive help for parameters
that appear in the Simulink Configuration Parameters dialog. This feature
provides quick access to a detailed description of the parameters, saving you
the time it would take to find the information in the Help browser.
To use the "What’s This?" help, do the following:
1 Placeyourcursoroverthelabelofaparameter.
2 Right-click. A What’s This? context menu appears.
For example, the following figure shows the What’s This? context menu
appearing after a right-click on the Start time parameter in the Solver
pane.
21
SimEvents®Release Notes
3 Click What’s This? A context-sensitive help window appears showing a
description of the parameter.
New Demos
SimEvents software Version 2.2 (R2008a) introduces these new demos:
• Managing Race Conditions
• Avoiding Identical Seeds for Random Number Generators
• Seed Management Workflow for Random Number Generators
• Asynchronous Clock Domains
• Rate-Based Shared Processor
22
Also, the demo formerly named “Explicit Routing for Distributed Processing”
is now called “Distributed Processing for Multi-Class Jobs.”
Version 2.1 (R2007b) SimEvents®Software
Version 2.1 (R2007b) SimEvents Software
This table summarizes what’s new in Version 2.1 (R2007b):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Yes—Details labeled
as Compatibility
Considerations,
below. See also
Summary.
New features and changes introduced in this version are
• “Attribute Computations Using Embedded MATLAB Code” on page 23
• “Attributes Support Complex Values” on page 25
• “Enhanced Visibility and Lo g gi ng of Events” on p age 25
• “New Demos for Shared-Resource Applications and A dv ance d Techniques”
on page 26
• “Subsystem Connection Port for Entity Paths” on page 28
• “Configuration Parameters to Control Livelock” on page 28
• “Processing Events Via the Event Calendar Instead of Immediately” on
page 29
Fixed Bugs an d
Known Problems
Bug Reports
Includes fixes
Related
Documentation at
Web Site
No
• “Enhanced Support for Multiple Simultaneous Transitions in Switches
and Gate” on page 31
• “Change in Indexing in Attribute Scope Block” on page 33
Attribute Computations Using Embedded MATLAB Code
The A ttribute Function block lets you conveniently set and modify attributes
using Embedded MATLAB
Manipulate Attributes”.
®
code. For details, see “Writing Functions to
23
SimEvents®Release Notes
Simplifying a Model Using the Attribute Function Block
The following figures indicate recommended ways to multiply the absolute
value of an attribute by a constant in SimEvents software Version 2.1
(R2007b) and earlier versions. The earlier version is more complicated
because of necessary steps to ensure correct timing. By contrast, the Attribute
Function block ensures correct timing automatically.
24
Manipulating Attribute Value Using Attribute Function Block
Version 2.1 (R2007b) SimEvents®Software
Manipulating Attribute Value in Earlie r Versions
Attributes Support Complex Values
In Version 2 .1 (R2007b), attributes can assume complex values, not only
real values.
Enhanced Visibility and Logging of Events
In Version 2.1 (R2007b), SimEvents software changes the set of events that
appear in event logs:
• Event logs show a new kind of event, called an entity request event. This
event is a notification that an entity input port of a block has become
available. To understand the name entity request event, think of the
block as requesting an entity from a preceding block. For example, upon
becoming empty, a single server requests an entity from a preceding block.
A preceding block’s response to the notification might result in an entity
advancement.
25
SimEvents®Release Notes
In earlier versions, entity request events do not appear in event logs.
• Event logs show a new kind of event, calle d a storage completion event.
ThiseventexistsonlyinanOutputSwitchblockwiththeStore entity
before switching parameter s elected. When an entity arrives at the block,
the block schedules a storage completion event at the current simulation
time. Upon execution of the storage completion event, the b lock determines
whether the entity can advance to a subsequent block.
In earlier versions, storage completion ev ents do not appear in event logs.
• Event logs always show the events listed in the following table, regardless
of how you set the Resolve simultaneous signal updates according to
event priority parameter in the corresponding blocks. This parameter
determines whether the event priority is a number you specify in the block
dialog box or a system-level category denoted by
Events That Affect Entities and Are Caused By Signal-Based Events
SYS1.
Event
Entity generation
Counter reset Entity Departure Counter
Gate even t (gate opening
or gate closing)
Release
Port selection
In earlier versions, event logs show these events only if you select Resolve
simultaneous signal updates according to event priority in the
block dialog box.
Also, event logs and entity logs in Version 2.1 (R2007b) are more readable and
contain hyperlinks that highlight the corresponding blocks.
Block
Event-Based Entity Generator
Enabled Gate
Release Gate
Input Switch, Output Switch, P ath Combiner
New Demos for Shared-Resource Applications and
Advanced Techniques
SimEvents software Version 2.1 (R2007b) introduces these new d emonstration
models:
26
Version 2.1 (R2007b) SimEvents®Software
Tutorial Dem o s
• Server Blocks and S ervice Time
• Input and Output Switching
• Schedule Timeout and Cancel Timeout Blocks
Advanced Technique Demos
• Buffering for Variable-Size Messages
• Delayed Function Calls in Pulse Width Modulation
• Explicit Routing for Distributed Processing
• Markov-Modulated Poisson Process
• Queue with Flushing Capability
• Variable Entity Replication
• Variable-Capacity Queue
Application Demos
• Shared Communication Buffer Management
• Processor Sharing Via Time Slicing
Consolidation and Removal of Some Tutorial Demos
The new Server Blocks and Service Time demo replaces these earlier demos:
• Service Time from Attribute
• SpecifyingServiceTimeinSingleServer
• Specifying Service Time in Infinite Server Block
• Single Server Block Versus Infinite Server Block
The new Input and Output Switching demo replaces these earlier demos:
• Input Switching Using Signal
• Output Switching Using Signal
27
SimEvents®Release Notes
Changes in Categorization, Titles, and Content of Some Demos
SimEvents demos have been recategorized in the Help browser. Some demos
have changed their titles or content.
Title in Version 2.1 (R2007b) Title in Earlier Versions
Task Sharing with Two Levels of
Priority and Preemption
Multitasking with Dependent Tasks Multitasking Model with Dependent
Operating System with Prio riti zed
Task Execution
Entity Combiner for Assembling
Components (with simpler design
using the Entity Combiner and
Attribute Function blocks)
Also, the G/G/1 Queuing System and Little’s Law demo has a simpler design
using the Attribute Function and Embedded MATLAB Function blocks.
Preemptive Operating System with
Two Levels of Priority
Tasks
Operating System Model with
Prioritized Task Execution
Aggregation: Assembling a Vehicle
Chassis
Subsystem Connection Port for Entity Paths
The Conn blo ck represents an entity input port or entity output port in a
virtual subsystem. The model window’s Edit > Create Subsystem menu
option automatically creates connection ports. Copying the C onn block
from its library is a convenient w ay to add more entity ports to an existing
subsystem.
28
Configuration Parameters to Control Livelock
The SimEvents pane of the Configuration Parameters dialog box offers new
parameters for setting thresholds related to livelock. Also, the Execution
order of simultaneous events parameter has been renamed Execution
order.
Version 2.1 (R2007b) SimEvents®Software
New Parameter
Maximum events
per block
Maximum events
per model
For more information, see “Livelock Prevention” or the configuration
parameter descriptions.
Description
Limit the number of entity generation, service
completion, subsystem execution, and function-call
events that each SimEvents block performs at each
fixed time instant.
Limit the total number of events scheduled via the
event calendar at each fixed time instant.
Processing Events Via the Event Calendar Instead of Immediately
In Version 2.1 (R2007b), SimEvents software changes its processing of each
event in the next table when you do not select Resolve simultaneous
signal updates according to event priority in the corresponding block.
In this case, the event has a system-level event priority denoted by
and the application processes the event via the event calendar. Using the
event calendar decouples the scheduling and the execution of events. “Event
Sequencing” describes how the application processes multiple simultaneous
events.
SYS1,
Events That Affect Entities and Are Caused By Signal-Based Events
Event
Entity generation
Counter reset Entity Departure Counter
Gate event (gate opening
or gate closing)
Release
Port selection
Also, each entity request event has a system-level priority denoted by SYS2,
and the application processes the event via the event calendar.
Block
Event-Based Entity Generator
Enabled Gate
Release Gate
Input Switch, Output Switch, Path Combiner
29
SimEvents®Release Notes
In earlier versions, the application applies “immediate” processing for entity
requests by storage blocks, as well as for events in the table when you do not
select the Resolve simultaneous signal updates according to event
priority parameter in the corresponding block.
For details about supported events and the processing of s imultaneous events,
see “Working with Events” and “Managing Simultaneous Events”.
Compatibility Considerations
Most models are unaffected by the change in event processing. However,
some models might behave differently, because events processed immediately
in earlier versions are deferred to the event calendar in SimEvents software
Version 2.1 (R2007b). Models that behave differently tend to involve cycles
in simulation processing and cascades of simultaneous events (for example,
an event has multiple consequences that occur at time T,eachofwhichhas
further consequences also at time T).
Example Showing Change in Behavior
30
The model below attempts to simultaneously a dvance one entity from each
queue, whenever both queues are nonempty.
Suppose that the top queue contains one entity and an entity arrives at
the previously empty bottom queue. Assuming that no block in the model
has its Resolve simultaneous signal updates according to event
priority parameter selected, the entity arrival has the following cascade
of consequences:
1 The bottom queue updates its #n output signal to 1.
Version 2.1 (R2007b) SimEvents®Software
2 The discrete event subsystem evaluates the condition (A AND B) and
returns a value of 1. The previous value of this signal was 0.
3 EachofthetwoReleaseGateblocksdetectsavalue-changeeventatitsvc
signal input port. In SimEvents software Version 2.1 (R2007b), each of the
two gates schedules a release event on the event calendar.
4 One gate opens, which has these consequences:
a An entity advances from the corresponding queue to the sink.
b The corresponding queue updates its #n output signal to 0.
c The discrete event subsystem reevaluates the condition (A AND B) and
returns a value of 0.
5 In Version 2.1 (R2007b), the other gate opens, which has these
consequences:
a An entity advances from the corresponding queue to the sink.
b The corresponding queue updates its #n output signal to 0.
c The discrete event subsystem reevaluates the condition (A AND B) and
returns a value of 0.
In earlier version s, the gates do not schedule release events on the event
calendar if the corresponding Resolve simultaneous signal updates
accordingtoeventpriorityparameter is not selected. As a result, step 4c
negates the value-change event at the other gate and step 5 does not occur.
This example involves cycles in simulation processing, because an event at
thegateaffectsthevalueofthe#n signal of a preceding block. This example
involves cascades of simultaneous events, because the new value of 1 for the
condition (A AN D B) causes two release events, each of which causes the
condition (A AND B) to assume the value 0.
Enhanced Support for Multiple Simultaneous
Transitions in Switches and Gate
Theblocksinthistablemodeltheeffects of all transitions in their input
signals, even if multiple transitions occu r simultaneously.
31
SimEvents®Release Notes
Block Input Signal
Enabled Gate
Input Switch
Output Switch
Path Combiner
In earlier versions of SimEvents software, selecting the Resolve
simultaneous signal updates according to event priority option causes
the blocks to model only the last transition at a given value of the simulation
clock.
en
p
p
p
Compatibility Considerations
The behavior of some simulations changes depending o n whether the
application models intermediate transitions in a n en or p input signal in
the blocks in the table above.
32
Example Showing Change in Behavior
In the model below, the en signal transitions from 0 to 1 and then from 1 to 0
in the same time in stant. Earlier versions model only the latter transition, so
the gate does n ot open. Version 2.1 (R2007b) models both transitions, so the
gate opens and then closes in the same time instant.
Version 2.1 (R2007b) SimEvents®Software
Change in I
When you se
block, it
correspo
versions
ttheXvaluefromparameter to
creates a plot that reflects 1-based indexing. That is, the first entity
nds to a data point whose value on the horizontal axis is 1. In earlier
, the plot reflects 0-based indexing.
ndexing in Attribute Scope Block
Index in the Attribute Scope
33
SimEvents®Release Notes
Version 2.0 (R2007a) SimEvents Software
This table summarizes what’s new in Version 2.0 (R2007a):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Yes—Details labeled
as Compatibility
Considerations,
below. See also
Summary.
New features and changes introduced in this version are
• “Attributes Support Multidimensional Values” on page 34
• “Combining and Splitting Entities” on page 35
• “Timeout Feature Establishes Entity Time Limits” on page 35
• “New Demos for Video Processing , Communications, and Architecture
Modeling” on page 37
• “Output Switch Block Options for Sto rage and Initial Condition” on page 37
• “Entity Departure Counter Block Can Create Attribute” on page 39
• “Changes in Names of Parameters Related to Event Priorities” on page 40
• “Change in Default Entity Type of Entity Generators” on page 4 2
Fixed Bugs an d
Known Problems
Bug Reports
Includes fixes
Related
Documentation at
Web Site
No
34
• “Obsolete Blocks” on page 42
Attributes Suppor t Multidimensional Values
Version 2.0 (R2007a) introduces new versions of the Get Attribute and Set
Attribute blocks in a new Attributes library. The new blocks offer these
enhancements compared to the earlier versions:
• Attributes can assume values that are vectors, matrices, or
multidimensional arrays with up to 32 dimensions, not just scalars. This
enhancement facilitates modeling dense payloads via attributes.
Version 2.0 (R2007a) SimEvents®Software
• Each instance of a Set Attribute block can assign an arbitrary number
of attributes, and each instance of a Get Attribute block can retrieve an
arbitrary number of attributes.
• The dialog boxes use a grid on a single tab, making it easier for you to see
the entire list of attributes that a block sets or gets.
Compatibility Considerations
If your legacy models contain Get Attribute or Set Attribute blocks from
the earlier library, those blocks continue to work in Version 2.0 (R2007a).
However, the blocks are considered obsolete, as described in “Obsolete Blocks”
on page 42.
Combining and Splitting Entities
The new Entity Combiner block lets you combine entities, analogous to
combining components to create a larger whole. The block prov ides options for
managing information (attributes and timers) associated with the component
entities, so you can think of the operation as bundling the information that
entities carry with them.
You can configure the Entity Combiner block to make the combining operation
reversible via the Entity Splitter block.
The Entity Combiner and Entity Splitter blocks reside in the new Entity
Management library.
Timeout Feature Establishes Entity Time Limits
You can mo del point-to-point t iming constraints b y limiting the amount of
time an entity spends during the simulation on designated entity paths.
Exceeding the limit causes the entity to depart immediately from the storage
block where it resides, such as a queue, w hen the clock reaches the time limit.
To learn how to use this feature, see “Forcing Departures Using Timeouts” in
the SimEvents user guide documentation.
The timeout feature involves ne w blocks, as well as new parameters in
existing blocks.
35
SimEvents®Release Notes
New Block
Purpose
Schedule Timeout Schedule timeout event for each
entity
Cancel Timeout Cancel time out event for each entity
Existing Blocks with N ew Timeout-Related Parameters
• FIFO Queue
• LIFO Queue
• Priority Queue
• Infinite Server
• N-Server
• Single Server
• Output Switch
New Parameter of Existing
Purpose
Blocks
Enable TO port for timed-out
entities on Timeout tab
Provide a TO entity output port
through which an entity departs
upon timing out
36
Number of entities timed out on
Statistics tab
Output a signal, #to,thatindicates
the number of entities that have
timedoutfromtheblocksincethe
start of the simulation
Compatibility Considerations
If you save a model containing a queue, server, or Output Switch block using
V2.0 (R2007a), then opening the model in V1.2 (R2006b) produces warnings
like these:
Warning: In instantiating linked block 'mysys/FIFO Queue' :
FIFO Queue block (mask) do es not have a parameter named
'EnableTOPort'.
Warning: In instantiating linked block 'mysys/FIFO Queue' :
Version 2.0 (R2007a) SimEvents®Software
FIFO Queue block (mask) do es not have a parameter named
'StatNumberTimedout'.
Saving the model in the earlier version prevents the warnings from
reappearing, but causes the block to omit timeout-related ports and behavior
if you later open the model in V2.0 (R2007a).
New Demos for Video Processing, Communications,
and Architecture Modeling
Version 2.0 (R2007a) introduces these new demonstration models:
Tutorial Dem o s
• Transporting Multidimensional Data Using A ttrib utes
• Packet Creation, Transmission and Error Analysis
Application Demos
• Distributed Video Processing
• Distributed Processing Resource Modeling
• Video Streaming Over Bandwidth-Limited Communication Channel
• Bit Timing Recovery Using Fixed-Rate Resampling and SimEvents
Change in ARQ Demo
The Selective-Repeat Automatic Repeat Request demo reverses the
interpretation of the CRC check compared to V1.2 (R2006b). The
interpretation now matches that of the similar Go-Back-N Automatic Repeat
Request demo. In V2.0 (R2007a), both demos use a CRC check value of 1
to correspond to an ACK message.
Output Switch Block Options for Storage and Initial Condition
The Output Sw itch block offers enhancements that can prevent the need
for additional blocks to set initial conditions or to prevent latency. T he new
parameters apply to signal-based switching and are available only when you
set Switchin g criterion to
From signal port p. The new parameters are
37
SimEvents®Release Notes
in the table below. For details, see “Output Switching Based on a Signal”
and the block’s reference page.
New Parameter Purpose
Specify initial port
selection
Initial port selection The entity output port that the block selects
Store entity before
switching
Status of pending entity
on Statistics tab
Forotherchangesinthisreleasethataffect parameters of the Output Switch
block, see “Timeout Feature Establishes Entity Time Limits” on page 35 and
“Changes in Names of Parameters Related to Event Priorities” on page 40.
Determine w hether the block uses an initial
port selection from the dialog box.
when the simulati on begins. The block uses
this value instead of the p signal until the
signalhasitsfirstsampletimehit.
If you select this option, the block can store
one entity at a time. Furthermore, the
block decouples its arrival and departure
processing to give other blocks in the
simulation an opportunity to update the p
signal if appropriate. If you do not select
this option, the block processes an arrival
and departure as an atomic operation and
assumes that the p signal is already up to
date at the given time.
Output a signal, pe, that indicates when the
block stores an entity after trying and failing
to output it. A value of 0 indicates when the
storage location is empty.
38
Compatibility Considerations
In some cases, the block enhancements let you optionally simplify models that
you do not need to share with users of earlier versions:
• If your model precedes an Output Switch block with a Signal Latch block
to create an initial condition for the p signal, and if the p signal does
not branch to become an input for another block, then you can remove
Version 2.0 (R2007a) SimEvents®Software
the Signal Latch block and instead use the new Specify initial port
selection option in the switch block.
• If your model precedes an Output Switch block with a Single Server block
whose Service time parameteriszeroandwhosesolepurposewasto
ensure an up-to-date p signal, then you can remove the Single Server
block and instead use the new Store entity before switching option
in the switch block.
If you save a model containing an Output Switch block using V2.0 (R2007a),
then opening the model in V1.2 (R2006b) pro duces warnings like these:
Warning: In instantiating linked block 'mysys/Output Switch' :
Output Switch block (mask) does not have a parameter named
'InitialConditionsOpt'.
Warning: In instantiating linked block 'mysys/Output Switch' :
Output Switch block (mask) does not have a parameter named
'InitialConditions'.
Warning: In instantiating linked block 'mysys/Output Switch' :
Output Switch block (mask) does not have a parameter named
'EntityBufferOpt'.
Warning: In instantiating linked block 'mysys/Output Switch' :
Output Switch block (mask) does not have a parameter named
'StatPendingEntity'.
Saving the model in the earlier version prevents the warnings from
reappearing, but causes the block to omit ports and behavior related to the
V2.0 (R2007a) enhancements if you later open the model in V2.0 (R2007a).
Entity Departure Counter Block Can Create Attribute
If you configure the Entity Departure Counter block to write the count to an
attribute, then you can select the new Create attribute if not present
parameter to have the block create the attribute if it does not already exist.
The block then sets the value of the attribute according to the entity count.
In earlier versions, the block sets the value of the attribute but does not
create it.
39
SimEvents®Release Notes
Changes in Names of Parameters Related to Event Priorities
Parameters related to optional prioritiesofeventshavebeenrenamedtobe
more suggestive of how the option works. The name Resolve simultaneous
signal updates according to event priority replaces names that start
with Specify event priority. In a subset of affected blocks, the name
Event priority replaces similar names. For more information about what
the parameters mean, see “Choosing How to Resolve Simultaneous Signal
Updates”.
The table below itemizes the blocks and parameters that have changed.
Block
Discrete Event
Inport
Enabled Gate Specify event priority
Entity
Departure
Counter
Event-Based
Entity
Generator
Parameter Name in
V1.2 (R2006b)
Specify event priority
for e xecuting subsystem
Subsystem execution
event priority
for gate opening and
closing
Specify event priority
for counter reset
Specify event priority
for e ntity generation
Generation event
priority
Parameter Name in
V2.0 (R2007a)
Resolve simultaneous
signal updates
according to event
priority
Event priority
Resolve simultaneous
signal updates
according to event
priority
Resolve simultaneous
signal updates
according to event
priority
Resolve simultaneous
signal updates
according to event
priority
Event priority
40
Version 2.0 (R2007a) SimEvents®Software
Block
Parameter Name in
V1.2 (R2006b)
Input Sw itch Specify event priority
for port selection
Output Switch Specify event priority
for port selection
Path Combiner Specify event priority
for port precedence
selection
Release Gate Specify event priority
for gate opening
Signal Latch
Specify event priority
for writing to memory
Parameter Name in
V2.0 (R2007a)
Resolve simultaneous
signal updates
according to event
priority
Resolve simultaneous
signal updates
according to event
priority
Resolve simultaneous
signal updates
according to event
priority
Resolve simultaneous
signal updates
according to event
priority
Resolve simultaneous
signal updates
according to event
priority on Write tab
Signal-Based
Event to
Function-Call
Event
Specify event priority
for reading from
memory
Specify event priority
for function-call
generation
Function-call event
priority
Resolve simultaneous
signal updates
according to event
priority on Read tab
Resolve simultaneous
signal updates
according to event
priority
Event priority
41
SimEvents®Release Notes
Block
Signal-Based
Function-Call
Event
Generator
This change merely renames parameters and does not change the behavior of
affected blocks.
Parameter Name in
V1.2 (R2006b)
Specify event priority
for function-call
generation
Function-call event
priority
Parameter Name in
V2.0 (R2007a)
Resolve simultaneous
signal updates
according to event
priority
Event priority
Change in Default Entity Type of Entity Generators
ThedefaultvalueofEntity type in the Time-Based Entity Generator and
Event-Based Entity Generator block is
value is
saved model but only affects new instances of the block that you copy from
the library to a model.
Standard. This change in default value does not affect blocks in a
Blank. In earlier versions, the default
Obsolete Blocks
The table below indicates blocks that are obsolete as of the current version or
that are planned to be removed in a future version.
42
Obsolete Block
Get Attribute block from
simeventsattributes1
library
Set Attribute block from
simeventsattributes1
library
Removed from
Ver sion
Future version
Future version
Replacement
Get Attribute block from
simeventsattributes2
library
Set Attribute block from
simeventsattributes2
library
Version 1.2 (R2006b) SimEvents®Software
Version 1.2 (R2006b) SimEvents Software
This table summarizes what’s new in Version 1.2 (R2006b):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Yes—Details labeled
as Compatibility
Considerations,
below. See also
Summary.
New features and changes introduced in this version are
• “Event-Based Sequence Generator Block” on page 43
• “New Tutorial and Application Demos” on page 44
• “Event Translation Block Supports Delay from a Signal” on page 44
• “Routing Blocks Support Unlimited Entity Ports” on page 45
• “Initial Outputs of SimEvents Blocks” on page 46
• “History Options and Other Changes in Scope Blocks” on page 48
• “Parameters for L ognormal Distribution” on page 49
• “SimEvents Blocks Compatible with Accelerator Mode” on page 50
• “Livelock Detection” on page 50
Fixed Bugs an d
Known Problems
Bug Reports
Includes fixes
Related
Documentation at
Web Site
No
Event-Based Sequence Generator Block
The new Event-Based Sequence block provides data to an event-driven
process by producing a scalar event-based output signal whose values come
from a vector. The block selects the next value from the vector upon each
notification from a port of a subsequent block. For example, if you connect
the Event-Based Sequence block to the t input port of a Single Server block,
the v alues in the vector become the service times for the entities arriving at
the server. You provide the values in the vector, but do not need to know in
advance when the entities arrive at the server.
43
SimEvents®Release Notes
New Tutorial and
Version 1.2 (R20
Tutorial Dem o s
• Entity Combin
• Task Sharing w
• Multitasking
Application
• Go-Back-N A
• Operating S
• Ethernet L
• Anti-Lock
• Anti-Loc
• Anti-Loc
Event Tr
The Sign
of a func
signal
block l
input s
al-Based Event to Function-Call Event block can delay its generation
tion call by an amount of time that you specify using either an input
or the Function-call time delay parameter. In V1.1 (R2006a), the
ets you specify the delay amount using the parameter, but no t an
ignal.
06b) introduces these n ew demonstration models:
er for Assembling Components
ith Two Levels of Priority and Preemption
with Dependent Tasks
Demos
utomatic Repeat Request
ystem with Prioritized Task Execution
ocal Area Network
Braking System (ABS) Model
k Braking System (ABS) Model with Queuing Delay
k Braking System (A BS) Model U sing CAN C ommunications
anslation Block Supports Delay from a Signal
Application Demos
44
ess the new feature, select Specify event priority for function-call
To acc
ation (or, in V2.0 (R2007a), select Resolve simultaneous signal
gener
updat
dela
nonn
esaccordingtoeventpriority). Then set the new Function-call
yfromparameter to
egative-valued signal to the t signalinputportthatappearsontheblock.
Signal port t, as shown. Then connect a
Compatibility Considerations
If you sav
or Discre
model in V
e a model containing the Signal-Based Event to F unction-Call Event
te Event Subsystem block using V1.2 (R2006b), then opening the
1.1 (R2006a) produces warnings like these:
Version 1.2 (R2006b) SimEvents®Software
Warning: In instantiating linked block 'mysys/Signal-Based
Event to Function-Call Event' : Signa l-Ba sed Event to FunctionCall Event block (mask) do es not have a parameter named
'FunctionCallDelayFrom'.
g the model in the earlier version prevents the warnings from
Savin
earing, but causes the Signal-Based Event to Function-Call Event block
reapp
tthet input port if you later open the model in V1.2 (R2006b).
to omi
Rout
The N
Path
out
can
onl
ing Blocks Support Unlimited Entity Ports
umber of entity input ports parameter of the Input Switch and
Combiner blocks can be any positive integer. The Number of entity
put ports parameter of the Output Switch and Replicate blocks also
be any positive integer. In V1.1 (R2006a), these parameters can assume
y the values 1, 2, 3, and 4.
45
SimEvents®Release Notes
Compatibility Considerations
If you save a model in which one of the blocks listed above has more than four
entity input ports or more than four entity output ports, then the model will
not work in V1.1 (R2006a).
Initial Outputs of SimEvents Blocks
All SimEvents blocks now have well-defined initial values for any numerical
output signals they produce.
The initial value of an output signal of a SimEvents block is in effect from the
start of the simulation until the block updates the output signal for the first
time during the simulation. For example, if an N-Server block is configured to
produce a #n output signal representing the number of entities in the server,
then #n has a well-defined initial value of 0 at the start of the simulation. The
initial value persists until the first arrival of an entity at the N-Server block,
which could occur well after the start of the simulation, if at all.
The block reference pages indicate the initial values of the block output
signals.
46
Compatibility Considerations
If you connect the Signal Latch block to a ts, tr,orvc signal input port of a
SimEvents block, the input port might detect an event at the start of the
simulation in V1.1 (R2006a) that no longer occurs in V1.2 (R2006b). This
is because the S ign a l Latch block assumes its initial condition in a true
initialization stage in V1.2 (R2006b) rather than slightly after the simulation
start in V1.1 (R2006a). If your model relies on an event at the start of the
simulation (to invoke a discrete event subsystem or generate an event or an
entity, for example), then you might see a change in simulation behavior
between the two versions.
For example, the model below uses a Discrete Event Subsystem block to
compute a signal that indicates whether a gate is open or closed.
Version 1.2 (R2006b) SimEvents®Software
Subsystem Invoked at Simulation Start in V1.1 (R2006a), but Not V1.2 (R2006b)
In V1.1 (R2006a), the Signal Latch block’s output signal has a sample time hit
at the start of the simulation. This sample time hit invokes the subsystem,
which initializes the gate’s en input signal to 1. As a result, the gate is open at
the start of the simulation. In V1.2 (R2006b), the Signal Latch block does not
haveasampletimehitatthestartofthesimulation, so the initial condition
of the subsystem’s outport determines the initial condition of the gate’s en
input signal. As a result, the gate is closed at the start of the simulation.
An alternative approach that works in both versions is to move the Signal
Latch block so that it follows the Discrete Event Subsystem block. The Signal
Latch block directly provides the ga t e’s initial condition.
Correct Gate Initialization in Both V1.1 (R2006a) and V1.2 (R2006b)
47
SimEvents®Release Notes
History Options
The following bl
Limit data point
box:
• Attribute Sco
• Instantaneou
• Instantaneo
• Signal Scope
• X-Y Attribu
• X-Y Signal S
The parame
balance da
it later, e
less or no
(R2006a)
then open
ven if the scope is closed during part or all of the simulation. Caching
, if you have the scope closed for the first T seconds of simulation and
ocks include new Store data when scope is closed and
pe
s Entity Counting Scope
us Event Counting Scope
te Scope
cope
ters determine how much data the blocks cache, letting you
ta visibility with simulation efficiency. Caching data lets you view
data accelerates the simulation and uses less memory. In V1.1
the scope, you can view only the data for t>T.
and Other Changes in Scope Blocks
stoparameters on the new Data History tab of the dialog
Other Changes in Scope Blocks
Version
scope b
1.2 (R2006b) changes some aspects of the way you interact with the
locks:
48
• APanto
• APara
• Doubl
V1.1
open
butt
• The a
spe
you
cur
shi
th
olbar button lets you move your view of a plot.
meters toolbar button opens the block dialog box.
e-clicking on the block opens the plot if it is not already open. In
(R2006a), double-clicking on the block opens the block dialog box. To
the block dialog box in V1.2 (R2006b), click the Parameters toolbar
on on the plot.
utoscale feature n o longer changes the i nitia l axis limits that you
cify in the b lock dialog box. A new Save axes limits menu option lets
update the initial axis limits to match the plot’s current limits. The
rent limits might differ from their initial values due to stretching,
fting, panning, zooming, or autoscaling operations that occurred since
e initial values were last set.
Version 1.2 (R2006b) SimEvents®Software
• The former Open at start of simulation parameter is now called Open
scope at start of simulation and has moved from the Figure tab of
the dialog box to the Plotting tab.
The scope blocks also plot initial conditions without a plotting marker. In
V1.1 (R2006a), initial conditions typically do not appear in plots.
Finally, the scope blocks run significantly faster in V1.2 (R2006b).
Compatibility Considerations
If your legacy models contain scope blocks that plot more than 1000 points,
then the default values of the new Stor e data when scope is closed and
Limit data points to parameters cause the scope to retain only the last
1000 points. To plot all points, set Store data when scope is closed to
Unlimited.
If you save a model containing a scope block using V1.2 (R2006b), then
opening the model in an earlier version produces warnings about the
parameters that are not in the earlier block. For example,
Warning: In instantiating linked block 'mysys/Attribute
Scope' : Attribute Scope b loc k (mask) does not have a parameter
named 'DataStoreOption'.
Warning: In instantiating linked block 'mysys/Attribute
Scope' : Attribute Scope b loc k (mask) does not have a parameter
named 'DataPointsLimit'.
Saving the model in the earlier version prevents the warnings from
reappearing, but also causes the block to use default values for the new
parameters if you later open the model in V1.2 (R2006b).
Parameters for Lognormal Distribution
The Event-Based Random Number block produces random numbers from
a lognormal distribution when you set the Distribution parameter to
Lognormal. Different texts use different parameterizations of the lognormal
distribution. V1.2 (R2006b) renames some parameters in this block to clarify
the relationship between a lognormal random variable X and the normal
random variable log(X).
49
SimEvents®Release Notes
V1.1 (R2006a) Parameter Name
Scale
Shape Sigma
V1.2 (R2006b) Parameter Name
Mu
Compatibility Considerations
The block behaves the same in V1.1 (R2006a) and V1.2 (R2006b) because the
change m erely renames parameters. However, the parameter names in V1.2
(R2006b) more accurately reflect the block’s behavior.
SimEvents Blocks Compatible with Accelerator Mode
All SimEvents blocks are compatible with accelerator mode. Version 1.1
(R2006a) does not support simulating models in accelerator mode if the
models contain the Event-Based Random Number block.
Livelock Detection
SimEvents software can detect livelock during a simulation. When it detects
livelock, it halts the simulation with an error message that indicates too
many simultaneous events. In V1.1 (R2006a), livelock can potentially cause
MATLAB software to crash.
For details, s ee “Livelock Prevention”.
50
Compatibility Considerations
It is possible for the application to consider a situation to be livelock when
it is actually a large but finite loop. Such simulations might work in V1.1
(R2006a) but not in V1.2 (R2006b).
Version 1.1 (R2006a) SimEvents®Software
Version 1.1 (R2006a) SimEvents Software
This table summarizes what’s new in Version 1.1 (R2006a):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Yes—Details labeled
as Compatibility
Considerations,
below. See also
Summary.
New features and changes introduced in this version are described here.
Fixed Bugs an d
Known Problems
Bug Reports
Includes fixes
Related
Documentation at
Web Site
No
Replicate Block Supports Partial Replication
The Replicate block supports partial replication and offers more flexibility
when you choose complete replication. New parameters in the block’s dialog
box are in th e table below.
Parameter
Replicate entity when Lets you choose w hether the
Description
block accepts arriving entities for
replication only when all entity
output ports are not blocked or
whenever at least one entity output
port is not blocked. The first option
is the default.
If an output port becomes
blocked during replication
Number of entities departed
Determines how the block responds
if a departure through one entity
output port causes another entity
output port to become blocked.
Toggles the optional output signal
#d, representing the number of
departed entities.
51
SimEvents®Release Notes
Compatibility Considerations
By default in V1.1 (R2006a), when a departure through one entity output port
causes another entity output port to become blocked, the result is a discarded
entity with no error or warning message. If this phenomenon occurs in your
legacy models, then the result in V1.0 (R14SP3+) might be an error message
or incorrect behavior. If you want to learn when this phenomenon occurs in
your legacy models that you simulate using V1.1 (R2006a), then set If an
output port becomes blocked during replication to either
discard entity
,orError.
The default values of the other new parameters added in V1.1 (R2006a) are
consistent with the block’s behavior in V1.0 (R14SP3+), so legacy mode ls need
no changes to accommodate thes e new features.
If you save a model containing the Replicate block using V1.1 (R2006a),
then opening the model in V1.0 (R14SP3+) produces warnings about the
parameters that are not in the V1.0 block. For example,
Warning: In instantiating linked block 'mysys/Replicate' :
Replicate block (mask) does not have a parameter named
'ReplicateEntityWhen'.
Warning: In instantiating linked block 'mysys/Replicate' :
Replicate block (mask) does not have a parameter named
'ActionUponBlocking'.
Warning: In instantiating linked block 'mysys/Replicate' :
Replicate block (mask) does not have a parameter named
'StatNumberDeparted'.
Warn and
52
Also, simulating that model under V1.0 causes the block to exhibit its V1.0
behavior, which is to omit a #d output signal and to replicate the arriving
entity only when all entity output ports are not blocked. Saving the model
in V 1.0 prevents the warnings from reappearing in V1.0 but also causes the
block to exhibit its V1.0 behavior if you later open the model in V1.1.
Version 1.0 (R14SP3+) SimEvents®Software
Version 1.0 (R14SP3+) SimEvents Software
This table summarizes what’s new in Version 1.0 (R14SP3+):
New Features and
Changes
Yes
Details below
Version
Compatibility
Considerations
Not applicable
New features introduced in this version are described here.
Fixed Bugs an d
Known Problems
Bug Reports No
Related
Documentation at
Web Site
Introduction to SimEvents
SimEvents software extends Simulink software with tools for modeling and
simulating discrete-event systems using queues and servers. With SimEvents
software you can create a discrete-event simulation model to simulate the
passing of entities through a network of queues, servers, gates, and switches
based on events. The software provides an integrated environment for
modeling hybrid dynamic systems containing continuous-time, discrete-time,
and discrete-event components.
A key concept that SimEvents software adds to the Simulink environment
is that of entities, which are discrete items of interest in a discrete-event
simulation. For example, entities could represent messages to be
communicated or parts to be assembled. Entities can carry data in one
or more scalar structures called attributes. For example, attributes could
represent destinations of messages or dimensions of parts.
The libraries in SimEvents software con ta in blocks that can
• Create entities
• Store entities in a queue
• Serve or delay entities
• Forbid or al low en t i ties to depart, depending on specified criteria
• Manipulate the paths on which entities travel
53
SimEvents®Release Notes
• Attach data or timers to entities
• Create plots using data from entities or statistics gathered during
simulation
• Manipulate or generate discrete events that can a ffect the behavior of
blocks and entities
• Control the simulation timing in situations where event-driven behavior
and time-driven behav ior interact
54
Compatibility Summary for SimEvents®Software
Compatibility Summary for SimEvents Software
This table summarizes new features and changes that might cause
incompatibilities when you upgrade from an earlier version, or wh en you
use files on multiple versions. Details are provided in the description of the
new feature or change.
Version (Release) New Features and Changes with
Version Compatib ility Impact
Latest Version
V3.1 (R2010a)
V3.0 (R2009b)
V2.4 (R2009a) See the Compatibility
See the Compatibil ity
Considerations subheading
for each of these new features or
changes:
• “Block Operations Information in
Debugger” on page 5
• “Changes in Behavior of Pending
Entity Signals” on page 5
• “Parameters and Parameter
Values Being Removed” on page
10
None
Considerations subheading
for each of these new features or
changes:
• “Event Logging Options Removed
from Configuration Parameters
Dialog Box” on page 15
• “Discrete Event Signal to
Workspace Block Clarifies
Timing” on page 17
V2.3 (R2008b)
V2.2 (R2008a)
None
None
55
SimEvents®Release Notes
Version (Release) New Features and Changes with
Version Compatib ility Impact
V2.1 (R2007b) See the Compatibility
Considerations subheading
for each of these new features or
changes:
• “Processing Events Via the E vent
Calendar Instead of Immediately”
on page 29
• “Enhanced Support for Multiple
Simultaneous Transitions in
Switches and Gate” on page 31
V2.0 (R2007a) See the Compatibility
Considerations subheading
for each of these new features or
changes:
56
• “Attributes Support
Multidimensional Values” on
page 34
• “Timeout Feature Establishes
Entity Tim e Limits” on page 35
• “Output Switch Block Options for
Storage and Initial Condition” on
page 37
Compatibility Summary for SimEvents®Software
Version (Release) New Features and Changes with
Version Compatib ility Impact
V1.2 (R2006b) See the Compatibility
Considerations subheading
for each of these new features or
changes:
• “Event Translation Block
Supports Delay from a Signal” on
page 44
• “Routing Blocks Support
Unlimited Entity Ports” on
page 45
• “Initial Outputs of SimEvents
Blocks” on page 46
• “History Options and Other
Changes in Scope Blocks” on page
48
• “Parameters for Lognormal
Distribution” on page 49
• “Livelock Detection” on page 50
V1.1 (R2006a) See the Compatibility
Considerations subheading
under “Replicate Block Supports
Partial Replication” on page 51.
V1.0 (R14SP3+)
Not applicable
57
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