Error defining a discontinous function: "Output argument "y2" (and possibly others) not assigned a value in the execution with "x2" function

I tried defining a function, x2(t), such that:

As such, I implemented in in MatLab as follows:

function y2 = x2(t)

if 0 <= t & t < 0.2 % First condition, 0 <= t < 0.2

y2 = 3;

elseif 0.2 <= t & t < 0.4 % Second condition, 0.2 <= t < 0.4

y2 = 1.5;

elseif 0.4 <= t & t < 0.7 % Third condition, 0.4 <= t < 0.7

y2 = -1.5;

elseif 0.7 <= t & t < 1 % Fourth condition, 0.7 <= t < 1

y2 = -3;

end

end

However, I wasn't able to run the following code:

t = 0:1/20000*pi:1;

a = x2(t);

As I got the following error message: Output argument "y2" (and possibly others) not assigned a value in the execution with "x2" function.

What exactly is causing the error and how should I implement this differently so that the function works?

Answer 1

[MJFcoNaN]

Your function does not consider a vector as input.

Use for loop, such as:

a=NaN(length(t));
for ii = 1:length(t)
    a(ii)=x2(t(ii));
end

or more efficiently modify your function by vectorization.

[Stephen23]

https://www.mathworks.com/help/matlab/matlab_prog/vectorization.html

[Tomás Rodríguez Yagui]

It worked, many thanks!