User manual MATLAB SIMEVENTS RELEASE NOTES

[. . . ] SimEvents® Release Notes How to Contact The MathWorks Web Newsgroup www. mathworks. com/contact_TS. html Technical Support www. mathworks. com comp. soft-sys. matlab suggest@mathworks. com bugs@mathworks. com doc@mathworks. com service@mathworks. com info@mathworks. com Product enhancement suggestions Bug reports Documentation error reports Order status, license renewals, passcodes Sales, pricing, and general information 508-647-7000 (Phone) 508-647-7001 (Fax) The MathWorks, Inc. 3 Apple Hill Drive Natick, MA 01760-2098 For contact information about worldwide offices, see the MathWorks Web site. SimEvents® Release Notes © COPYRIGHT 2005­2010 by The MathWorks, Inc. The software described in this document is furnished under a license agreement. The software may be used or copied only under the terms of the license agreement. [. . . ] Using the event calendar decouples the scheduling and the execution of events. "Event Sequencing" describes how the application processes multiple simultaneous events. Events That Affect Entities and Are Caused By Signal-Based Events Event Entity generation Counter reset Gate event (gate opening or gate closing) Release Port selection Block Event-Based Entity Generator Entity Departure Counter Enabled Gate Release Gate Input Switch, Output Switch, Path Combiner Also, each entity request event has a system-level priority denoted by SYS2, and the application processes the event via the event calendar. 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 simultaneous 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, each of which has further consequences also at time T). Example Showing Change in Behavior The model below attempts to simultaneously advance 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. 30 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 Each of the two Release Gate blocks detects a value-change event at its vc 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 versions, the gates do not schedule release events on the event calendar if the corresponding Resolve simultaneous signal updates according to event priority parameter 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 the gate affects the value of the #n signal of a preceding block. This example involves cascades of simultaneous events, because the new value of 1 for the condition (A AND 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 The blocks in this table model the effects of all transitions in their input signals, even if multiple transitions occur simultaneously. 31 SimEvents® Release Notes Block Enabled Gate Input Switch Output Switch Path Combiner Input Signal en p p p 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. Compatibility Considerations The behavior of some simulations changes depending on whether the application models intermediate transitions in an en or p input signal in the blocks in the table above. 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 instant. Earlier versions model only the latter transition, so the gate does not open. Version 2. 1 (R2007b) models both transitions, so the gate opens and then closes in the same time instant. 32 Version 2. 1 (R2007b) SimEvents® Software Change in Indexing in Attribute Scope Block When you set the X value from parameter to Index in the Attribute Scope block, it creates a plot that reflects 1-based indexing. That is, the first entity corresponds to a data point whose value on the horizontal axis is 1. [. . . ] Such simulations might work in V1. 1 (R2006a) but not in V1. 2 (R2006b). 50 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. Fixed Bugs and Known Problems Bug Reports Includes fixes Related Documentation at Web Site No New features and changes introduced in this version are described here. 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 the table below. Parameter Replicate entity when Description Lets you choose whether the 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. [. . . ]