How to find all default transitions in stateflow programmatically?

I want to be able to find all default transitions in a stateflow (in Charts,subcharts,etc). I am using find('-isa','Stateflow.Transition','-and','Source',[]) But this is not accurate and i am getting transitions that are just not connected to a source. Is there any other way ?

[Muthukumar Ganesan]

Hi,

I'm wondering, is there any way to have a transition without a source except default transition. I think the above command would be sufficient, may be as an additional check you can include "Source0block=0".

Thanks.

Answer 1

[Purvaja]

Hello @TPar

I see that you wish to segregate default transitions from dangling transitions. You can achieve this by collecting all the transitions in a chart and classifying them based on their source and destination objects. By applying simple conditions, you can then filter or exclude whichever category you don’t need.

I have pasted below a copy of the MATLAB code I used, along with the output it generated and the corresponding Stateflow diagram. Feel free to adjust the code to suit your exact requirement (e.g., ignoring dangling transitions, or printing only defaults).

Stateflow dummy model:

Code:

% % Load the model that consists of the chart you wish to find from. 

for c = charts'
    % Get all transitions inside this chart
    transitions = c.find('-isa','Stateflow.Transition');
    
    for t = transitions'
        src = t.Source;
        dst = t.Destination;
        
        % --- Format source ---
        if isempty(src)
            srcStr = '[NONE]';
        elseif isa(src,'Stateflow.State')
            srcStr = ['State:' src.Name];
        elseif isa(src,'Stateflow.Junction')
            srcStr = sprintf('Junction(ID=%d)', src.Id);
        else
            srcStr = class(src);
        end
        
        % --- Format destination ---
        if isempty(dst)
            dstStr = '[NONE]';
        elseif isa(dst,'Stateflow.State')
            dstStr = ['State:' dst.Name];
        elseif isa(dst,'Stateflow.Junction')
            dstStr = sprintf('Junction(ID=%d)', dst.Id);
        else
            dstStr = class(dst);
        end
        
        % --- Print classification ---
        if isempty(src) && ~isempty(dst)
            fprintf(' Default transition -> %s\n', dstStr);
        elseif ~isempty(src) && ~isempty(dst)
            fprintf(' Transition: %s -> %s\n', srcStr, dstStr);
        elseif ~isempty(src) && isempty(dst)
            fprintf(' Dangling transition from %s -> [NONE]\n', srcStr);
        else
            fprintf(' Orphan transition [NO SOURCE] -> [NO DEST]\n');
        end
    end
end

Output:

 Default transition -> State:Init
 Transition: State:wait -> State:MAIN
 Default transition -> State:wait
 Dangling transition from State: -> [NONE]
 Default transition -> State:check
 Transition: State:check -> State:wait
 Default transition -> State:idle
 Transition: State:idle -> State:running

Refer to following resources to explore more about the same:

1. Default Transitions: https://www.mathworks.com/help/stateflow/api/stateflow.chart.defaulttransitions.html
2. Access objects in stateflow chart: https://www.mathworks.com/help/stateflow/api/accessing-existing-stateflow-objects.html

Hope this helps you!