Model Model Domain

A Modal Model is a finite set of Actors (other models), all having the same set of inputs and outputs, associated each with states in a finite state machine. For any given state, the associated Actor is known as a Refinement of this state. During each firing of this Modal Model the refinements associated with the current state in the state machine fires. Subsequently, the evaluation of guards in the state machine determines which state, if any, to transition to, thereby determining the next refinement to fire.

The modal domain replaces the fsm domain.


  1. Thomas Huining Feng, Edward A. Lee, Xiaojun Liu, Stavros Tripakis, Haiyang Zheng and Ye Zhou, "Modal Models," a chapter from
    Claudius Ptolemaeus, Editor, "System Design, Modeling, and Simulation Using Ptolemy II",, 2014. (included in the release as $PTII/doc/books/systems/PtolemyII_DigitalV1_02.pdf)
    The models provided in this chapter are also available online.
  2. Edward A. Lee. "Finite State Machines and Modal Models in Ptolemy II," Technical report, EECS Department, University of California, Berkeley, UCB/EECS-2009-151, December, 2009.
  3. Edward A. Lee, Stavros Tripakis. "Modal Models in Ptolemy," Proceedings of 3rd International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools (EOOLT 2010), p. 11-22, 3, October, 2010.