Patent ID: 6779006
Filing Date: 2004-08-17
Classification: G06F

Abstract:
A method for subtracting a first interval from a third interval to produce a resulting interval given knowledge that the third interval is the sum of the first interval and a second interval, comprising:computing a left endpoint of the resulting interval; wherein if the left endpoint of the third interval is negative infinity, the left endpoint of the resulting interval is assigned to be negative infinity, otherwise, the left endpoint of the resulting interval is computed by subtracting a left endpoint of the first interval from a left endpoint of the third interval using a floating-point arithmetic unit, and rounding down to a nearest smaller floating-point number; and computing a right endpoint of the resulting interval; wherein if the right endpoint of the third interval is positive infinity, the right endpoint of the resulting interval is assigned to be positive infinity, otherwise, the right endpoint of the resulting interval is computed by subtracting a right endpoint of the first interval from a right endpoint of the third interval using the floating-point arithmetic unit, and rounding up to a nearest larger floating-point number; whereby producing the resulting interval does not cause an exception condition when handling infinite or empty intervals.