Can't identify the condition under which the variable is not defined in a function

The following is a code that is written for certain function I need inside the matlab function in simulink. a1,b1,c1 are the values that are being updated from outside the function block. These values will get updated according to the output y of the function block. When the code is run a message is being shown. "y is not assigned on certain paths". But I can't seem to find such a condition under which y is not defined.

Answer 1

[Walter Roberson]

Your while is an infinite loop if any B(i) < 20.

The analysis is noticing that y is only assigned if there is at least one loop of the "for", but the analysis is not strong enough to prove that n is positive (because B must not be empty because that would require u to have been empty and that would have created an error before you got there.)

In cases like this, just initialize the output variable before the for loop.

[Sreerag Kunnathu Sugathan]

Thank you. But from within that loop itself, output will come out, right? I expected that output signal to increase B(i). Am I missing something here?

[Walter Roberson]

Your "for" loop never changes B(i)