I am working with a simple data vector and I need to find the occurrences of certain values. Here is a simplified version of the code, which amounts to a for loop and an equality check:
data=[1.5 1.6 1.7 1.8 1.9 2 2.1 2.2];
Running the code I see that in the first case, where only the first and last check should give an empty result, also other iterations give the "1×0 empty double row vector" output. For example, given that index=94.6 during debug, if I write the same line as "find(data==index)" it fails, if I write it with the corresponding index value it works (find(data==94.6) works). The positions where the check fails are always the same. The second for loop, with all the items matching, never fails.
Could it be a problem with the double format precision with logical operators? I have tried it in Matlab R2017a and R2013a, on different computers. I also tried to rewrite the same code without the find function, and the result is the same. If I change both data and index ranges, the behavior is the same but the check fails at different positions. All the numbers are in double format. If I multiply everything by 10, so that the numbers are integers, both loops work fine.
I would like to understand why, with decimal numbers, it doesn't work in just ONE case, the one where not all the numbers have a match.