Before you can build a simulation application for a model, you
must fix syntax errors. Follow these steps to check the MATLAB® function
Open the function
the chart in the
that you updated in Program a MATLAB Function in a Chart.
The editor automatically checks your function code for errors and recommends corrections.
In the Stateflow® Editor, select Code > C/C++ Code > Build Model.
If there are no errors or warnings, the
Builder window appears and reports success. Otherwise, it lists errors.
For example, if you change the name of local function
a nonexistent local function
errors appear in the Diagnostic Viewer.
The diagnostic message provides details of the type of error and a link to the code where the error occurred. The diagnostic message also contains a link to a diagnostic report that provides links to your MATLAB functions and compile-time type information for the variables and expressions in these functions. If your model fails to build, this information simplifies finding sources of error messages and aids understanding of type propagation rules. For more information about this report, see MATLAB Function Reports in the Simulink® documentation.
In the diagnostic message, click the
link after the function name
meanstats to display
the offending line of code.
The offending line appears highlighted in the editor.
Correct the error by changing
avg and recompile. No errors are found and the
compile completes successfully.
You use simulation to test your MATLAB functions for run-time errors that are not detectable by Stateflow. When you simulate your model, your MATLAB functions undergo diagnostic tests for missing or undefined information and possible logical conflicts as described in Check MATLAB Functions for Syntax Errors. If no errors are found, the simulation of your model begins.
Follow these steps to simulate and debug the
during run-time conditions:
In the function editor, click the dash
-) character in the left margin of this line:
len = length(vals);
A small red ball appears in the margin of this line, indicating that you have set a breakpoint.
Start simulation for the model.
If you get any errors or warnings, make corrections before you try to simulate again. Otherwise, simulation pauses when execution reaches the breakpoint you set. A small green arrow in the left margin indicates this pause.
To advance execution to the next line, select Step.
Notice that this line calls the local function
If you select Step here, execution advances
past the execution of the local function
track execution of the lines in the local function
select Step In instead.
To advance execution to the first line
of the called local function
avg, select Step
Once you are in the local function, you can advance through one line at a time with the Step tool. If the local function calls another local function, use the Step In tool to step into it. To continue through the remaining lines of the local function and go back to the line after the local function call, select Step Out.
Select Step to
execute the only line in
avg finishes its execution, you see
a green arrow pointing down under its last line.
Select Step to
return to the function
Execution advances to the line after the call to
To display the value of the variable
place your pointer over the text
len in the function
editor for at least a second.
The value of
len appears adjacent to your
You can display the value for any data in the MATLAB function
in this way, no matter where it appears in the function. For example,
you can display the values for the vector
placing your pointer over it as an argument to the function
or as an argument in the function header.
You can also report the values for MATLAB function data
in the MATLAB Command Window during simulation. When you reach
a breakpoint, the
debug>> command prompt
appears in the MATLAB Command Window (you might have to press Enter to see it). At this prompt, you can inspect
data defined for the function by entering the name of the data, as
shown in this example:
debug>> len len = 4 debug>>
As another debugging alternative, you can display the execution result of a function line by omitting the terminating semicolon. If you do, execution results appear in the MATLAB Command Window during simulation.
To leave the function until it is called again and the breakpoint is reached, select Continue.
At any point in a function, you can advance through the execution of the remaining lines of the function with the Continue tool. If you are at the end of the function, selecting Step does the same thing.
Click the breakpoint to remove it and select Quit Debugging to complete the simulation.
In the model, the computed values of
appear in the Display blocks.
To control data range checking, select or clear Simulation > Debug > MATLAB & Stateflow Error Checking Options > Data Range.
To specify a range for input and output data, follow these steps:
In the Model Explorer, select the MATLAB function input or output of interest.
The Data properties dialog box opens in the Dialog pane of the Model Explorer.
In the Data properties dialog box, click the General tab and enter a limit range, as described in Limit range properties.