William M. Kahan

Research Areas

Computer Architecture & Engineering (ARC)
Scientific Computing (SCI)
Computer architecture; Scientific computing; Numerical analysis

Biography

William "Velvel" Kahan was born in Canada and attended the University of Toronto for both his undergraduate and graduate studies in mathematics, and was eventually hired there as a professor. He joined the Berkeley faculty in 1968 with a joint appointment in the Math Department and as a member of the new Computer Science Department in the College of Letters and Science--before it merged with the EECS Department in the College of Engineering in 1973. He retired from the University in 2008. Kahan was instrumental in creating the IEEE 754-1985 standard for floating-point computation in the late 1970s and early 1980s. He developed a program called "paranoia' in the 1980s to test for potential floating point bugs and developed the Kaham summation algorithm which helps minimize errors introduced when adding a sequences of finite precision floating point numbers. Kahan won the ACM A.M. Turing Award in 1989.

Education

1958, Ph.D., Mathematics, University of Toronto
1956, Master's, Mathematics, University of Toronto
1954, B.A., Mathematics, University of Toronto

Selected Publications

W. M. Kahan, "Is there a small skew Cayley transform with zero diagonal?," Linear Algebra and Its Applications, vol. 417, no. 2-3, pp. 335-341, Sep. 2006.
R. Bhatia, W. M. Kahan, and R. Li, "Pinchings and norms of scaled triangular matrices," Linear and Multilinear Algebra, vol. 50, no. 1, pp. 15-21, March 2002.
W. M. Kahan and R. Li, "Unconventional schemes for a class of ordinary differential equations - With applications to the Korteweg-de Vries Equation," J. Computational Physics, vol. 134, no. 2, pp. 316-331, July 1997.
W. M. Kahan and R. Li, "Composition constants for raising the orders of unconventional schemes for ordinary differential equations," Mathematics of Computation, vol. 66, no. 219, pp. 1089-1099, July 1997.
W. M. Kahan, "Analysis and refutation of the LCAS," ACM SIGNUM Newsletter, vol. 26, no. 3, pp. 2-15, July 1991.
J. Demmel and W. M. Kahan, "Accurate singular values of bidiagonal matrices," SIAM Journal on Scientific and Statistical Computing, vol. 11, no. 5, pp. 873-912, Sep. 1990.
W. M. Kahan, "Branch cuts for complex elementary functions, or much ado about nothing's sign bit," in The State of the Art in Numerical Analysis: Proc. 3rd Joint IMA/SIAM Conf., A. Iserles and M. J. D. Powell, Eds., Institute of Mathematics and Its Applications Conference Series, Vol. 9, Oxford, England, UK: Oxford University Press, 1987, pp. 165-211.
W. J. Cody, J. T. Coonen, D. M. Gay, K. Hanson, D. Hough, W. M. Kahan, R. Karpinski, J. Palmer, F. N. Ris, and D. Stevenson, "A proposed radix- and word-length-independent standard for floating-point arithmetic," ACM SIGNUM Newsletter, vol. 20, no. 1, pp. 86-100, Jan. 1985.
W. M. Kahan, "Mathematics written in sand," in Proc. Joint Statistical Meeting of the American Statistical Association, Alexandria, VA: American Statistical Association, 1983, pp. 12-26.
W. M. Kahan, B. N. Parlett, and E. Jiang, "Residual bounds on approximate eigensystems of nonnormal matrices," SIAM J. Numerical Analysis, vol. 19, no. 3, pp. 470-484, June 1982.
C. Davis, W. M. Kahan, and H. F. Weinberger, "Norm-preserving dilations and their applications to optimal error bounds," SIAM J. Numerical Analysis, vol. 19, no. 3, pp. 445-469, June 1982.