CONTINUOUS TIME MODE-DRIVEN SIMULATIONS IN A GRAPHICAL MODELING ENVIRONMENT

• US 20090044171A1
• Filed: 07/10/2008
• Published: 02/12/2009
• Est. Priority Date: 07/12/2007
• Status: Active Grant

• Current Assignee: The MathWorks, Inc.
• Original Assignee: The MathWorks, Inc.
• Inventors: Avadhanula, Srinath
• Granted Patent: US 8,387,000 B2
• Time in Patent Office: Days
• US Class Current: 717/105
• CPC Class Codes: G06F 8/20 Software design
• CPC Class Codes: G06F 8/34 Graphical or visual programming

Abstract

A system, computer-readable medium, and method includes providing a control flow graph including at least one condition. An update control flow graph is automatically generated based on the provided control flow graph, where execution of the update control flow graph includes an evaluation of the condition. The update control flow graph and a value corresponding to the evaluated condition is stored. An output control flow graph based on the provided control flow graph is automatically generated, where execution of the output control flow graph is based on the stored value corresponding to the evaluated condition. A mode transition control flow graph configured to identify mode transitions for the control flow graph at one or more time intervals is automatically generated and the update control flow graph is re-executed based on the generated mode transition control flow graph.

Claims

1. A computing device-implemented method, comprising:

providing a control flow graph including at least one condition;

automatically generating an update control flow graph based on the provided control flow graph,

where execution of the update control flow graph includes an evaluation of the condition;

storing the update control flow graph and a value corresponding to the evaluated condition;

automatically generating an output control flow graph based on the provided control flow graph,

where execution of the output control flow graph is based on the stored value corresponding to the evaluated condition;

automatically generating a mode transition control flow graph configured to identify mode transitions for the control flow graph at one or more time intervals; and

re-executing the update control flow graph based on the generated mode transition control flow graph.

2. The computing-device implemented method of claim 1, where automatically generating the update control flow graph and storing the update control flow graph and the evaluated condition comprises:

creating a mode stack having an entry corresponding to the condition in the provided control flow graph; and

storing, in the mode stack, the value corresponding to the evaluation of the condition upon execution of the update control flow graph.

3. The computing-device implemented method of claim 2, where automatically generating the update control flow graph further comprises:

replacing the condition in the provided control flow graph with a modePush function corresponding to the condition, where the modePush function pushes the value to the entry in the mode stack.

5. The computing-device implemented method of claim 1, where automatically generating the output control flow graph further comprises:

replacing the condition in the control flow graph with a modePop function corresponding to the condition, where the modePop function retrieves the corresponding value stored in the mode stack.

6. The computing device-implemented method of claim 1, further comprising:

creating a mode transition stack having an entry corresponding to the condition in the provided control flow graph;

storing, in the mode transition stack, a value corresponding to an occurrence of a mode transition at the condition; and

determining whether to re-execute the update control flow graph based on the values stored in the mode transition stack.

7. The computing-device implemented method of claim 6, where automatically generating the mode transition control flow graph further comprises:

replacing the condition in the provided control flow graph with a mtPush function corresponding to the condition, where the mtPush function retrieves the corresponding value stored in the mode stack and determines a mode transition stack value corresponding to the condition.

8. The computing device-implemented method of claim 6, where the value corresponding to an occurrence of a mode transition comprises a binary signal indicative of either a mode transition or no mode transition.

9. The computing device-implemented method of claim 1, where the value corresponding to the evaluated condition comprises a Boolean value.

10. The computing device-implemented method of claim 1, where the provided control flow graph comprises an ill-conditioned control flow graph including at least one of:

unstructured control flow, a loop, a temporary variable, a non-static single assignment form, function calls, or recursive elements.

11. The computing device-implemented method of claim 1,

determining whether predetermined conditions have been identified;

and

not automatically generating the update control flow graph and the output control flow graph when predetermined conditions have been identified.

12. The computing device-implemented method of claim 1, further comprising:

providing a state diagram, where the state diagram includes at least a state and a transition, where at least one of the state and the transition is associated with the condition; and

automatically generating the provided control flow graph corresponding to at least a portion of the state diagram that includes the condition.

13. The computing device-implemented method of claim 12, where the state diagram further includes at least one junction, and where transition is associated with the at least one junction.

14. The computing device-implemented method of claim 12, where the state diagram is provided in a graphical modeling system executed in a multi-core processing unit.

15. The computing device-implemented method of claim 12, where the state diagram is provided in a graphical modeling system executed across multiple distributed computing devices.

16. The computing device-implemented method of claim 15, where the multiple distributed computing devices are connected via a network.

17. The computing device-implemented method of claim 12, where the state diagram is provided in a graphical modeling system executed as a service available to a computing device via a network.

18. A computer-readable medium that stores instructions executable by at least one processor, the computer-readable medium comprising:

one or more instructions for generating a graphical state diagram model having at least one state and at least one transition,

where the at least one transition includes an absolute time condition having at least one absolute time operator; and

one or more instructions for translating the absolute time condition into a non-absolute time condition.

19. The computer-readable medium of claim 18, where the one or more instructions for translating the absolute time condition into a non-absolute time condition comprise:

one or more instructions for inserting an entry action into the at least one state, defining an initial state time in terms of a simulation time; and

one or more instructions for converting the absolute time condition into a non-absolute time condition using the initial state time and the simulation time.

20. A computing device-implemented method, comprising:

generating a graphical state diagram model having at least one state and at least one transition,

where the at least one transition includes an absolute time condition having at least one absolute time operator; and

translating the absolute time condition into a non-absolute time condition.

21. The computing device-implemented method of claim 20, where translating the absolute time condition into a non-absolute time condition further comprises:

inserting an entry action into the at least one state, defining an initial state time in terms of a simulation time; and

converting the absolute time condition into a non-absolute time condition using the initial state time and the simulation time.

22. A computer-readable medium that stores instructions executable by at least one processor, the computer-readable medium comprising:

one or more instructions for providing a control flow graph including at least one condition;

one or more instructions for automatically generating an update control flow graph based on the provided control flow graph,

where execution of the update control flow graph includes an evaluation of the condition;

one or more instructions for storing the update control flow graph and a value corresponding to the evaluated condition;

one or more instructions for automatically generating an output control flow graph based on the provided control flow graph,

where execution of the output control flow graph is based on the value corresponding to the evaluated condition stored during execution of the update control flow graph;

one or more instructions for automatically generating a mode transition control flow graph configured to identify mode transitions for the state diagram at one or more time intervals based on the provided control flow graph; and

re-executing the update control flow graph based on the generated mode transition control flow graph.

23. The computer-readable medium of claim 22, where the one or more instructions for automatically generating an update control flow graph based on the provided control flow graph further comprise:

one or more instructions for creating a mode stack having an entry corresponding to the condition in the provided control flow graph; and

one or more instructions for storing, in the mode stack, the value corresponding to the evaluation of the condition upon execution of the update control flow graph.

24. The computer-readable medium of claim 23, further comprising:

one or more instructions for retrieving, from the mode stack, the value corresponding to the evaluation of the condition; and

one or more instructions for outputting, from the output control flow graph, a result based on the retrieved value corresponding to the evaluation of the condition.

25. A computing device-implemented method, comprising:

providing a state diagram, wherein the state diagram includes at least a state and a transition, where at least one of the state and the transition includes a condition associated therewith;

automatically generating an unmodified control flow graph corresponding to at least a portion of the state diagram that includes the condition;

automatically generating an update control flow graph based on the unmodified control flow graph,

where execution of the update control flow graph includes an evaluation of the condition;

storing the update control flow graph and a value corresponding to the evaluated condition;

automatically generating an output control flow graph based on the unmodified control flow graph,

where execution of the output control flow graph is based on the value corresponding to the evaluated condition stored during execution of the update control flow graph;

automatically generating a mode transition control flow graph configured to identify mode transitions for the state diagram at one or more time intervals based on the unmodified control flow graph; and

re-executing the update control flow graph based on the generated mode transition control flow graph.

26. The computer-readable medium of claim 25, where the state diagram further includes at least one junction, and where transition is associated with the at least one junction.