Computing the Sign of a Dot Product Sum.

A real number usually cannot be exactly represented by a floating-point number in a computer. Namely, a floating-point number frequently stands for any real number in a specific interval. In this paper, we present a method for computing the sign of a dot product sum. Each initial datum that is a floating-point number is considered as an interval. With interval analysis and floating-point summation methods, an explicit formula for calculating the minimal interval of a dot product sum is presented. Error analysis and some examples are provided as well. Keywords: Floating-point arithmetic; Rounding error; Interval analysis. [ABSTRACT FROM AUTHOR]