How to compare that sequence of doubles are all “approximately equal” in Java?

Question

I have a method in java that returns a double number and I want to compare every double number that is returned every time I call the method(say 5 times), so that I can conclude

Answer 1

The Apache commons-math library provides the nice Precision class (see API Docs), that can compare doubles in different ways:

Precision.equals(a, b, 0.1); // Tell if |a-b| <= 0.1
Precision.equals(a, b, 10); // Tell if a and b are less than 10 Ulps apart
Precision.equalsWithRelativeTolerance(a, b, 0.05); // Tell if a and b are less than 5% apart