MATLAB: Unexpected for loop behaviour

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This for loop is supposed to run for 2 iterations i.e. for i=0 and i=-0.1 as variable outputOverVoltageChange_65 = -0.1. Why is it running for only i=0?

Best Answer

"Unexpected for loop behaviour"
The value -0.1 cannot be represented exactly using floating point numbers, and you could quite easily be using different values of "-0.1", even though you think that they are the same value:
>> V = -0.1
V =
-0.1000
>> V = V+eps
V =
-0.1000
>> fprintf('%.30f\n',V)
-0.099999999999999784000000000000
>> 0:-0.1:V
ans =
0
What you see printed in the command window is the closest representation to 5 or 16 significant digits, depending on your current format setting. To see the "real" value download James Tursa's FEX submission:
Use James Tursa's num2strexact and you will see that none of those values really have the exact value -0.1. All you are looking at is a representation of those floating point numbers displayed in the command window, to the precision defined by your format setting. Just because you see -0.1 displayed tells you nothing about the "real" floating point number's value.
Note that you can change how the value is displayed by changing the format.
You need to learn about the limits of floating point numbers. Start by reading these:
This is worth reading as well: