How I can solve the error "Data ... inferred as a variable size matrix" in Simulink?

Question

Victor Maciel 2021-4-26

2
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/813975-how-i-can-solve-the-error-data-inferred-as-a-variable-size-matrix-in-simulink

评论： esmail mobasher 2023-7-3

I wrote a Matlab function in Simulink. The compilation process detects that u data is a variable size matrix, but it isn't on my case.

The code is showed below. The error is:

Data 'u' is inferred as a variable size matrix, while its properties in the Model Explorer specify its size as inherited or fixed. Please check the 'Variable Size' check box and specify the upper bounds in the size field.

But when I check the 'Variable Size' option, other problems emerge, because all of my signals presents fixed size.

function u = buffer(d_uf, arrival_time)
% ------------------------------------------------------------------------
% Parameters
m = 1;
Nc = 36;
% ------------------------------------------------------------------------
persistent index u_old d_uf_ready time_old
% Initialization of persistent variables
if isempty(u_old)
    u_old = zeros(m,1);
end
if isempty(d_uf_ready)
    d_uf_ready = zeros(Nc*m,1);
end
if isempty(index)
    index = 1;
end
if isempty(time_old)
    time_old = 0;
end
% Condition to use the buffer
if arrival_time < time_old
    d_u = d_uf_ready(index:index+m-1);
    index = index + m; % Move the index to the next block position
else % Update the buffer and use the most recent available data 
    d_u = d_uf(1:m);
    index = 1 + m;      % Restart the index counter
    d_uf_ready = d_uf;  % Storing to the next time sample
end
% Obtaining control signal
u = d_u + u_old;
% Storing to the next time sample
u_old = u;
end