Brian S. McCormick created MATH-1386: ----------------------------------------
Summary: EPSILON value in org.apache.commons.math.util.MathUtils seems like half of what it should be Key: MATH-1386 URL: https://issues.apache.org/jira/browse/MATH-1386 Project: Commons Math Issue Type: Bug Environment: win 7 Reporter: Brian S. McCormick I've always used 1.1920929E-7 for dealing with float epsilon values. When dealing with double I've always used 2.220446049250313E-16 for epsilon. You have it defined in org.apache.commons.math.util.MathUtils as 1.1102230246251565E-16 which is half what I think it should be. I come up with these numbers using the following: float fEps = Float.intBitsToFloat(Float.floatToIntBits(1f) + 1) - 1; double dEps = Double.longBitsToDouble(Double.doubleToLongBits(1) + 1) - 1; Am I correct? I don't really know. I do know that float epsilon in every legacy C/C++ compiler etc I have ever used is defined as about 1e-7 and this is the value using the formula for fEps above. When I started doing comps using doubles instead of floats I started using the formula for dEps above which looks to me like the equivalent for double numbers. -- This message was sent by Atlassian JIRA (v6.3.4#6332)