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Executing a Simulator


There are a number of monitor commands for executing one or more transitions in process instances, and for stepping symbol by symbol within a transition.

Note:

During execution, you may be prompted for input before the execution can continue. See Run-time Prompting for more information.

Continuous Execution

To start executing the simulation program continuously, click the Go button in the Execute module, or enter the command Go. The execution continues until one of the conditions listed in Activating the Monitor becomes true, for instance when reaching a breakpoint. See also Stopping the Execution.

Note:

The button Forever, corresponding to the command Go-Forever, behaves very similar to the above. The difference is that the monitor does not become active when the system is completely idle. This feature is valuable when communicating with other simulations or applications.

Executing Until a Condition

To execute until a certain point in time:

  1. Choose Until Time in the Execute menu, or enter the command Proceed-Until. The command takes one parameter, the value of the simulation time when to stop executing.
  2. Enter a time value, either an absolute value (without sign) or a value relative to Now (with a `+' sign). That is, "7.5" is an absolute time value, whereas "+7.5" is the time value Now+7.5.

To execute until, but not including, the next timer output, click the Until Timer button in the Execute module, or enter the command
Proceed-To-Timer.

Executing Transitions

To execute the next transition, or the remainder of the current transition, click the Transition button in the Execute module, or enter the command Next-Transition.

To execute a number of transitions until a transition with a textual trace value > 0 has been executed, choose Until Trace in the Execute menu, or enter the command Next-Visible-Transition. This is very valuable when you have set the trace value for some "uninteresting" parts of the system to 0, and you want to skip over those parts.

Single-Stepping Symbols or Statements

To execute only the next SDL symbol, choose Over Symbol in the Execute menu, or enter the command Next-Symbol. This may execute several statements, and will step over procedure calls.

To execute only the next SDL statement, choose Over Stmt in the Execute menu, or enter the command Next-Statement. This will step over procedure calls.

Executing Procedures

The only way to follow the execution into a procedure is to use the following single-stepping functions.

To execute only the next SDL symbol, and to step into possible procedure calls, click the Symbol button in the Execute module, or enter the command Step-Symbol. This may execute several statements.

To execute only the next SDL statement, and to step into possible procedure calls, choose Into Stmt in the Execute menu, or enter the command Step-Statement.

To execute a procedure up to and including its return, choose Finish in the Execute menu, or enter the command Finish. In a process, this command behaves exactly like Next-Transition.

Stopping the Execution

To stop the execution of transitions and symbols manually:

Caution!

There are some situations in which it is not possible to stop the execution in this way, for instance in an endless loop within an SDL symbol. The only way to stop the simulator in these situations is to terminate the simulation program from the operating system, for instance by pressing <Ctrl+C>, in which case all simulation results are lost.


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