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Rules for Using the Operating Point of a Chart

An operating point is a snapshot of the state of a Simulink® model at a specific time during simulation. For a Stateflow® chart, an operating point includes:

  • Activity of chart states

  • Values of chart local data

  • Values of chart output data

  • Values of persistent data in MATLAB® functions and Truth Table blocks

For more information, see Using Operating Points in Stateflow.

Limitations on Values You Can Modify

An operating point does not include information about these elements:

  • Machine-parented data

  • Persistent data in custom C code

  • Persistent data in external MATLAB code

Therefore, you cannot modify the values of those elements.

Rules for Modifying Data Values

These rules apply when you modify data values:

  • You cannot change the data type or size. Scalar data must remain scalar. Vector and matrix data must keep the same dimensions. The only exception to this rule is Stateflow data of ml type (see ml Data Type for details).

  • For enumerated data types, you can choose only enumerated values from the type definition. For other data types, new values must fall within the range that you specify in the Minimum and Maximum parameters.

  • Use one-based indexing to define rows and columns of a matrix.

    Suppose that you want to change the value of an element in a 21-by-12 matrix. To modify the element in the first row and second column, type:

    c.state_name.data_name.Value(1,2) = newValue;

Rules for Modifying State Activity

These rules apply when you use the setActive method on an exclusive (OR) leaf state:

  • State-parented local data does not reinitialize.

  • The newly active state does not execute any entry actions. Similarly, the previously active state does not execute any exit actions.

    If you want these state actions to occur, you must execute them separately. For example, if your state actions assign values to data, you must assign the values explicitly.

  • The setActive method tries to maintain state consistency by:

    • Updating state activity for parent, grandparent, and sibling states

    • Resetting temporal counters for newly active states

    • Updating values of state output data (read-only)

    • Enabling or disabling function-call subsystems and Simulink functions that bind to states

  • The highlightActiveStates method also executes when these conditions are true:

    • The model is open.

    • The chart is visible.

    • The highlightActiveStates method has executed at least once, but not the removeHighlighting method.

Restriction on Continuous-Time Charts

After you load an operating point for a continuous-time chart, you can restart simulation from a nonzero time. However, you cannot modify the state activity or any data values, because the operating point for a continuous-time chart is read-only. For more information, see Continuous-Time Modeling in Stateflow.

No Partial Loading of a Operating Point

When you load an operating point, the complete operating point is available as a variable in the MATLAB base workspace. You cannot perform partial loading of an operating point for a subset of chart objects.

Restriction on Copying Operating Point Values

Use the clone method to copy an entire operating point to a new variable (see Methods for Interacting with the Operating Point of a Chart). You cannot copy a subset of operating point values, because the clone method works only at the chart level.

Suppose that you obtain a handle to the operating point of your chart using these commands:

blockpath = 'model/chart';
c = xFinal.get(modelOperatingPoint, blockpath);

Assignment statements such as stateCopy = c.state, dataCopy = c.data, and operatingPointCopy = c do not work. These assignments create copies of object handles, not operating point values.

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