Error while using embedded matlab function block in simulink

 I want to use this code in the simulink through embedded matlab function block.

    function [unew] = cycomplet(u,t)

    unew=[];
    unew = zeros(1, length(t));

    for i = 2:length(t)-1;

        if (u(i-1)<u(i))&& (u(i+1)<u(i));

            unew(i)=u(i);

        else unew(i)=0;

        end
    end

These code are working fine in matlab, but when i use these code in simulink through embedded matlab function block it is giving following two error.

*error No 1* Coder error:-Matlab function:-Size computation for unew (#23) failed. The size definition did not evaluate to a positive integer value.

error No 2* Error using ==> sf Size computation for unew (#23) failed. The size definition did not evaluate to a positive integer value.

Can anybody please tell me why this error is coming in simulink?? and how to resolve it??

Regards Jeevan Patil

[TAB]

Statement 'unew=[]' is useless as you are initializing unew in next statement.

What are the inputs to the block?

[Jeevan Patil]

Tabrez,

Yes unew=[] is useless, But even if i remove that it is giving the same error.

there are two input to this block. 1st input is vector and 2nd input will be also vector of time.

[TAB]

What are size of input vectors?

Which blocks are feeding these 2 inputs of embedded matlab block?

[Jeevan Patil]

presently for testing only, i am feeding 2 input through constant block. In constant block i am entering the input vector of dimension 1x101

[Walter Roberson]

Perhaps in your code you code disp() the actual size received for u and t ?

Answer 1

[Walter Roberson]

Simulink arrays cannot be completely variable sized. You must have a maximum length defined for them.

Also, if I recall past postings properly, Simulink does not permit empty arrays. We have no proof in the code you show that t will be non-empty and thus that length(t) will be positive.

[Walter Roberson]

What would your code compute if length(t) is 1 or 2 ? length(t)-1 would then be less than 2 so the for loop would not execute.

Sorry, we were both cleaning up the posting at the same time, so one of your responses got deleted. You were asking what to do and for examples of how to do it.

[Jeevan Patil]

if length(t) is 1 , my code is not calculating anything. Basically i want to find peak in the signal.

My output will be signal which is having values of peak only, rest of the values should be zero.