William Kahan

Who is William Kahan?

William Morton Kahan is a mathematician and computer scientist who received the Turing Award in 1989 for "his fundamental contributions to numerical analysis", and was named an ACM Fellow in 1994.

He attended the University of Toronto, where he received his Bachelor's degree in 1954, his Master's degree in 1956, and his Ph.D. in 1958, all in the field of mathematics. Kahan is now emeritus professor of mathematics and of electrical engineering and computer sciences at the University of California, Berkeley.

Kahan was the primary architect behind the IEEE 754-1985 standard for floating-point computation. He has been called “The Father of Floating Point,” since he was instrumental in creating the original IEEE 754 specification. Kahan continued his contributions to the IEEE 754 revision that led to the current IEEE 754 standard.

In the 1980s he developed the program "paranoia", a benchmark that tests for a wide range of potential floating point bugs. It would go on to detect the infamous Pentium division bug, and continues to have important uses to this day. He also developed the Kahan summation algorithm, an important algorithm for minimizing error introduced when adding a sequence of finite precision floating point numbers. He coined the term "The Table-Maker's Dilemma" for the unknown cost of correctly rounding transcendental functions to some preassigned number of digits.