[MATH-306] Method 'divide' in class 'Complex' uses a false formula for a special case resulting in erroneous division by zero.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.1, 1.2, 2.0
• Fix Version/s: 2.1

Environment

all

• Assignee: Unassigned
• Reporter: Joerg Huber
• Created: 24/Oct/09 14:23
• Updated: 14/Apr/10 00:05
• Resolved: 27/Oct/09 01:33

Description

The formula that 'divide' wants to implement is

( a + bi ) / ( c + di ) = ( ac + bd + ( bc - ad ) i ) / ( c^2 + d^2 )

as correctly written in the description.

When c == 0.0 this leads to the special case

( a + bi ) / di = ( b / d ) - ( a / d ) i

But the corresponding code is:

if (c == 0.0) {
return createComplex(imaginary/d, -real/c);
}

The bug is the last division -real/c, which should obviously be -real/d.