[MATH-489] FastMath acos fails when input abs value is less than about 5.7851920321187236E-300 - returns NaN

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2, 3.0
• Fix Version/s: 2.2, 3.0
• Assignee: Unassigned
• Reporter: Sebb
• Created: 19/Jan/11 17:11
• Updated: 23/Mar/11 20:35
• Resolved: 21/Jan/11 03:33

Description

FastMath acos fails when input absolute value is less than about 5.7851920321187236E-300

It returns NaN instead of an expected value close to PI/2.0

This appears to be due to the following code:

// Compute ratio r = y/x
double r = y/x;
temp = r * 1073741824.0;

r and temp can become infinite or Nan.