Simulink MATLAB Function for loop

Hi,

I have an aircraft model in a Matlab Function which is called from a matlab function.

What I am trying to achieve at the moment is simply getting a while loop set up in the function which outputs the value y every time the while loop is run through.

Currently the while loop does not output the value for each timestep, it simply jumps to the final limit condition.

Please see the code:

function [y,i] = fcn_06(u)
%#codegen
coder.extrinsic('tic','pause')
%Init
AC_Variables = struct('AC_position',double(zeros(3,1)));
i = 1;

%If AC Mode = 1 Then Initialise and Launch
AC_Variables.AC_position = u;

%Loop
while (i <= 200000)
[z] = calculation_06(AC_Variables);
AC_Variables = z;
y = AC_Variables.AC_position;
i = i + 1;
%pause(1)
end
y = AC_Variables.AC_position;
end

function [z]=calculation_06(AC_Variables)
%#codegen
AC_Variables.AC_position = AC_Variables.AC_position + 10;
z = AC_Variables;
end

How do I set it up to output the value at each step?

Thank you in advance.

Answer 1

[Anshuman]

Hello John,

To ensure that the value 'y' is output at each step of the while loop, you'll need to modify the function to store the intermediate results in an array. This way, you can capture the state of 'y' at each iteration. Here’s how you can adjust your code:

1. Allocate an array to store y for each iteration.
2. Save the value of y at each iteration in the array.
3. Return the array containing all intermediate values.

function [y, i] = fcn_06(u)
    %#codegen
    coder.extrinsic('tic', 'pause')
    
    % Init
    AC_Variables = struct('AC_position', double(zeros(3, 1)));
    i = 1;
    max_iterations = 200000;
    
    % Preallocate y to store results for each iteration
    y = zeros(3, max_iterations);
    
    % If AC Mode = 1 Then Initialise and Launch
    AC_Variables.AC_position = u;
    
    % Loop
    while (i <= max_iterations)
        [z] = calculation_06(AC_Variables);
        AC_Variables = z;
        
        % Store the current position in y
        y(:, i) = AC_Variables.AC_position;
        
        i = i + 1;
        % pause(1) % Uncomment if you want to slow down the loop for debugging
    end
    
    % Trim y to only include the filled values
    y = y(:, 1:i-1);
end

function [z] = calculation_06(AC_Variables)
    %#codegen
    AC_Variables.AC_position = AC_Variables.AC_position + 10;
    z = AC_Variables;
end

Hope it helps!