Error in simulink, the upper bound is not specified

Hello everyone,

I am trying to build a matrix with a matlab function in Simulink. However, I always get some error message and already tried to fix it with:

coder.varsize('y1', [1,L], [0 1]);

The error message is the following:

This is the matlab function

function [y1, y2, y3, L] = fcn(u, x, acc_y, acc_z,L,k)

coder.varsize('y1', [1,L], [0 1]);
coder.varsize('y2', [1,L], [0 1]);
coder.varsize('y3', [1,L], [0 1]);

if u == 0
y1 = zeros(L,1);
y2 = zeros(L,1);
y3 = zeros(L,1); 
elseif u  < 1
    r = randi([1 k(1)-L],1,1);
    y1 = x(1,r:r+L);
    y2 = acc_y(r:r+L,1);
    y3 = acc_z(r:r+L,1);
elseif u  < 5
    r = randi([1 k(2)-L],1,1);
    y1 = x(r:r+L,2);
    y2 = acc_y(r:r+L,2);
    y3 = acc_z(r:r+L,2);
elseif u  < 10
    r = randi([1 k(3)-L],1,1);
    y1 = x(r:r+L,3);
    y2 = acc_y(r:r+L,3);
    y3 = acc_z(r:r+L,3);
elseif u  < 15
    r = randi([1 k(4)-L],1,1);
    y1 = x(r:r+L,4);
    y2 = acc_y(r:r+L,4);
    y3 = acc_z(r:r+L,4);
elseif u  < 20
    r = randi([1 k(5)-L],1,1);
    y1 = x(r:r+L,5);
    y2 = acc_y(r:r+L,5);
    y3 = acc_z(r:r+L,5);
elseif u  < 25
    r = randi([1 k(6)-L],1,1);
    y1 = x(r:r+L,6);
    y2 = acc_y(r:r+L,6);
    y3 = acc_z(r:r+L,6);
elseif u  < 30
    r = randi([1 k(7)-L],1,1);
    y1 = x(r:r+L,7);
    y2 = acc_y(r:r+L,7);
    y3 = acc_z(r:r+L,7);
elseif u  < 35
    r = randi([1 k(8)-L],1,1);
    y1 = x(r:r+L,8);
    y2 = acc_y(r:r+L,8);
    y3 = acc_z(r:r+L,8);
elseif u  < 40
    r = randi([1 k(9)-L],1,1);
    y1 = x(r:r+L,9);
    y2 = acc_y(r:r+L,9);
    y3 = acc_z(r:r+L,9);
elseif u  < 45
    r = randi([1 k(10)-L],1,1);
    y1 = x(10,r:r+L);
    y2 = acc_y(r:r+L,10);
    y3 = acc_z(r:r+L,10);
elseif u  < 50
    r = randi([1 k(11)-L],1,1);
    y1 = x(r:r+L,11);
    y2 = acc_y(r:r+L,11);
    y3 = acc_z(r:r+L,11);
elseif u  < 55
    r = randi([1 k(12)-L],1,1);
    y1 = x(r:r+L,12);
    y2 = acc_y(r:r+L,12);
    y3 = acc_z(r:r+L,12);
elseif u  < 60
    r = randi([1 k(13)-L],1,1);
    y1 = x(13,r:r+L);
    y2 = acc_y(r:r+L,13);
    y3 = acc_z(r:r+L,13);
elseif u  < 65
    r = randi([1 k(14)-L],1,1);
    y1 = x(r:r+L,14);
    y2 = acc_y(r:r+L,14);
    y3 = acc_z(r:r+L,14);
elseif u  < 70
    r = randi([1 k(15)-L],1,1);
    y1 = x(r:r+L,15);
    y2 = acc_y(r:r+L,15);
    y3 = acc_z(r:r+L,15);
elseif u  < 75
    r = randi([1 k(16)-L],1,1);
    y1 = x(r:r+L,16);
    y2 = acc_y(r:r+L,16);
    y3 = acc_z(r:r+L,16);
else
    r = randi([1 k(17)-L],1,1);
    y1 = x(r:r+L,17);
    y2 = acc_y(r:r+L,17);
    y3 = acc_z(r:r+L,17);
end
L = L;

The setting of y1 is the following:

Answer 1

[Chaitanya Mallela]

you must specify a numerical upperbound in the size column in Ports and Data Manager to make Simulink realize a variable sized array. In this case you may declare size as [1,L].

Refer the documentation that demonstrates variable size declarations

https://www.mathworks.com/help/simulink/ug/declare-variable-size-inputs-and-outputs.html