Version 3.1 (R2010a) SimEvents Software :: SimEvents Release Notes (SimEvents®)

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

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 sedb.blklist function and are valid as inputs to the sedb.blkinfo function:

Discrete Event Signal to Workspace
Discrete Event Subsystem
Instantaneous Event Counting Scope

The sedb.blklist function sorts its Command Window output and cell array output by block names instead of by block identifiers.

Compatibility Considerations

If you have code that manipulates or indexes into the output cell array from sedb.blklist, you might need to update the code to reflect new rows or a 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	Yes	No
Infinite Server	Yes	Yes
N-Server	Yes	Yes
Output Switch	Yes	No
Single Server	Yes	No
Time-Based Entity Generator	Yes	No

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.

Compatibility Considerations

If your models use the pe or #pe signal to control simulation behavior, perform computations, or return results, your models might behave differently. The table summarizes the behavioral changes most likely to affect your models. For typical uses of the #pe signal, in which redundant sample time hits with the same value do not matter, the behavioral changes do not change the simulation results.

Affected Blocks	Change in Behavior
Event-Based Entity Generator Infinite Server N-Server Output Switch Single Server Time-Based Entity Generator	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 pending entity because it does not fail to depart. The same information is true for #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 Output Switch Single Server Time-Based Entity Generator	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 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 gate 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.
Event-Based Entity Generator Time-Based Entity Generator	When you configure the block to produce an error if an entity fails to depart, the error situation does not cause a sample time hit in pe. In this configuration, the block cannot store any pending entities, so there is no storage action to cause a sample time hit in pe. You see the effect of this change if, after the error occurs, you examine pe in the workspace or in a plot.
Infinite Server N-Server	If a pending entity departs and one or more pending entities remain in the block, the pe signal has a single sample time hit of 1. In earlier versions, in this situation, the signal has a sample time hit of 0 followed by a sample time hit of 1. Example In the next model, at T = 0.5, one pending entity departs from the server and one pending entity remains. In V3.1 (R2010a), pe has a sample time hit to indicate the departure of the pending entity. The value is 1 because the block still contains another pending entity. In earlier versions, pe has a sample time hit of 0 followed by a sample time hit of 1.

Affected Blocks

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 pending entity because it does not fail to depart.

The same information is true for #pe in blocks that offer this port.

Example

Event-Based Entity Generator
Infinite Server
N-Server
Output Switch
Single Server
Time-Based Entity Generator

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 hit occurs at the same simulation time, but in a different sequence compared to other simultaneous events.

Example

Event-Based Entity Generator
Time-Based Entity Generator

When you configure the block to produce an error if an entity fails to depart, the error situation does not cause a sample time hit in pe. In this configuration, the block cannot store any pending entities, so there is no storage action to cause a sample time hit in pe.

You see the effect of this change if, after the error occurs, you examine pe in the workspace or in a plot.

Infinite Server
N-Server

If a pending entity departs and one or more pending entities remain in the block, the pe signal has a single sample time hit of 1. In earlier versions, in this situation, the signal has a sample time hit of 0 followed by a sample time hit of 1.

Example

Renaming of Parameter to Enable Pending Entity Signal

Blocks that have an optional pe signal output port rename the parameter that you use to enable the port. The name in V3.0 (R2009b) is Status 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:

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 Sample time hit from port ts.

Blocks in Attributes Library Must Get or Set at Least One Attribute

These blocks no longer support a configuration in which the table in the dialog box is empty:

Get Attribute
Set Attribute

Parameters and Parameter Values Being Removed

Affected Block Affected Parameter What Happens When You Use the Parameter? Use This Instead Compatibility Considerations

Affected Block	Affected Parameter	What Happens When You Use the Parameter?	Use This Instead	Compatibility Considerations
FIFO Queue LIFO Queue Priority Queue	Status of pending entity departure is being removed.	In legacy models in which the parameter is set to `On`, the corresponding pe signal output port is inactive. In the library block, the parameter is unavailable.	Number of entities in queue	To update legacy models, set Status of pending entity departure to `Off`. For more information, see the technique in Determining Whether a Queue Is Nonempty. The technique yields similar, but not identical, information.
FIFO Queue LIFO Queue Priority Queue	Capacity must have a positive value.	Warns if you set the value to `0`.	A positive value. Alternatively, remove the block.	Remove queue blocks whose capacity is zero.

FIFO Queue
LIFO Queue
Priority Queue

Status of pending entity departure is being removed.

In legacy models in which the parameter is set to On, the corresponding pe signal output port is inactive.

In the library block, the parameter is unavailable.

Number of entities in queue

To update legacy models, set Status of pending entity departure to Off. For more information, see the technique in Determining Whether a Queue Is Nonempty. The technique yields similar, but not identical, information.

FIFO Queue
LIFO Queue
Priority Queue

Capacity must have a positive value.

Warns if you set the value to 0.

A positive value. Alternatively, remove the block.

Remove queue blocks whose capacity is zero.

Version 3.1.1 (R2010b) SimEvents Software

Version 3.0 (R2009b) SimEvents Software

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