Accessing all values of a certain field inside a structure array in Simulink

Hi everyone!

I have the following problem: I want to access all the values of a certain field inside a structure array with a user-defined function in Simulink. The structure array is a non-tunable parameter of the user-defined function. Here's an example of the structure array:

test_struct(1) = struct('A', 1, 'B', 2);
test_struct(2) = struct('A', 3, 'B', 4);

Now, when I try for example to only access the value of the field B via Matlab, I get:

>> [test_struct.B]

ans =

        2     4

However, if I try to do the same with a user-defined function in Simulink:

function y = fcn(test_struct)
    y = [test_struct.B];
end

I get the error message 'Referencing a component from array of non-scalar values is not supported for code generation.'

If I try to access the values of the structure array one by one, I get no errors in Simulink:

 test_struct(1).B
 test_struct(2).B

However, I would prefer not to access the values one by one since I do not want to use a loop. So how can I access all the values at once without getting the error?

Best, Ferros

Answer 1

[Naty S]

Amm, I didn't get an error with what you mentioned but maybe this will work:

test_struct(:).B

[Ferros]

Hi, I have tried this and it still resulted in the same error message. I am curious as to why you did not get an error? I have updated my question above with the user-defined function I am using in Simulink, did you try something similar?

[Naty S]

Yeah, so once i have placed it in a user defined function i did get the same error. Don't really have a solution for you. I have noticed that if you place the variable in a constant and input the constant into the function it works (In constant use [test_struct(:).B] ) but i don't know if that is an option for you. really weird though

[Mohammed Kagalwala]

Hi,

I currently get the same error when trying to logically index into a struct of the same setup as test_struct, i.e.

test_struct([true false]).B

I was wondering if you had found a solution to your problem?