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
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
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

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