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When do you call a comparison an epsilon comparison?


Asked by Colter Patrick on Dec 01, 2021 FAQ



If the magnitude of the difference of the two numbers is less than a very small value ( in this case), we consider the numbers equal. We usually refer to the small number representing allowable error as EPSILON. Thus, a comparison of this type is usually referred to as an EPSILON comparison.
One may also ask,
The problem with comparing doubles is that when you do a comparison between two different math results that are equal but which, due to rounding errors, aren't evaluating to the same value, they will have some difference...which is larger than epsilon, except on edge cases. And using a reliable epsilon value is also difficult.
Additionally, #416 – Use an Epsilon to Compare Two Floating Point Numbers. Because of problems with the precision of floating point numbers, two numbers that would ought to be considered equal might actually have different values. Because of this, you typically don’t want to use the == operator on floating point numbers, when checking for equality.
In this manner,
Thus, a comparison of this type is usually referred to as an EPSILON comparison. At the Python interactive prompt, enter the expression above and note the result. You should see something like the following: For the C++ example, consider the same code testing the two values of as shown above, but now using an EPSILON comparison:
Indeed,
There are numbers that exist between 0 and epsilon because epsilon is the difference between 1 and the next highest number that can be represented above 1 and not the difference between 0 and the next highest number that can be represented above 0 (if it were, that code would do very little):-.