Overwriting While-loop conditional with +Inf

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Douglas Bock
Douglas Bock on 20 Apr 2017
Edited: Andrew Newell on 21 Apr 2017
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
  3 Comments
Stephen23
Stephen23 on 21 Apr 2017
@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?

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Answers (2)

Andrew Newell
Andrew Newell on 21 Apr 2017
Edited: Andrew Newell on 21 Apr 2017
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.

hmi amid
hmi amid on 21 Apr 2017
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

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