Overwriting While-loop conditional with +Inf

In my code, I have this loop:

while a~=1 && b <= totCycles
  ...
end

I want the loop to run as long as the conditions hold, obviously.

Sometimes, however, I do not want the second condition. I want to effectively make it always true.

Setting totCycles = +Inf looke like the right way to do this, but it doesnt seem to work!

Any ideas why this might be? Or any other workaround?

Many Thanks

Doug

[Andrew Newell]

How exactly does it not work?

[Douglas Bock]

The loop keeps iterating, even if the first condition is no longer met.

[Stephen23]

@Douglas Bock: how do you know that the first condition is not met? How did you check this? Are the two values integer or floating point?

Answer 1

[Andrew Newell]

MATLAB evaluates a logical expression like your while condition from left to right. If a==1, it knows the expression is false and does not even look at the second part. So I suspect that a is a floating point number, and when you think it is equal to 1 it is not exactly equal to 1. See this FAQ.

Answer 2

[hmi amid]

You can try this :

 while a~=1 && (b <= totCycles || idontcare_b)
   ...
   idontcare_b = true % in a place you dont care about the value of b
 end