William Kahan

Ph.D. (Math., University of Toronto, 1958)

Professor Emeritus of Mathematics, and of E.E. & Computer Science
863 Evans Hall (Math), and 513 Soda Hall (CS)
Now that I am "retired", I work in my
offices sporadically at least once or
twice a week during each semester.
Phone: (510) 642-5638 (rings in both offices)
E-mail to me at this address obfuscated to diminish spam:
wkahan at (omit underscores) E_E_C_S_D0T_B_E_R_K_E_L_E_Y_D0T_E_D_U

My e-mail is read at most once every week or two. There is much too much of it.

Better ways to communicate with me are ...
... by paper mail: EECS Dept., MS#1776, Univ. of Calif., Berkeley CA 94720-1776
... by telephone (or leave a message for me to call back), or
... by visiting when I am in my office (telephone me first).
Use e-mail only if you must; but be advised that the University's
e-mail is not so secure that you can trust its confidentiality.


Awards etc.

Keynote Speaker at IEEE Sponsored ARITH 17 Symposium on Computer Arithmetic dedicated to W. Kahan, 2005
Foreign (Canadian) Associate, National Academy of Engineering, U.S.A., 2005
Distinguished Mentor of Undergraduate Research in the College of Letters & Science, 2004
American Academy of Arts & Sciences, 2003
IEEE Emanuel R. Piore Award, 2000
Honorary Doctor of Mathematics, University of Waterloo, Canada, 1998 (PDF file)
Soc. Indust. & Appl. Math., 1997 John von Neumann Memorial Lecture
ACM Fellow, 1994
Honorary Doctor of Mathematics, Chalmers Inst., Goteborg, Sweden, 1993
SIAM Activity Group on Linear Algebra, Prize for 1988-90's Outstanding Paper (with J. Demmel), 1991
ACM Turing Award, 1989
ACM 1st G. E. Forsythe Memorial Award, 1972

Selected Publications

7094II System Support for Numerical Analysis
IBM SHARE Secretarial Distribution SSD#159 Item C-4537 (1966), and in
Error in Numerical Computation, Univ. of Mich. Eng'g Summer Conf'ce #6818
Numerical Analysis (1968) (A retyped reproduction)(PDF file)
Analysis and Refutation of the LCAS
ACM SIGNUM Newsletter, Vol. 26, No. 3, July 1991, pp. 2-15.
Also, ACM SIGPLAN Notices, Vol. 27, No. 1, January 1992, pp.61-74.
Accurate Singular Values of Bidiagonal Matrices
(with J. Demmel), SIAM J. Scientific Statistical Computation, Vol. 11, No. 5, 1990, pp. 873-912.
Branch Cuts for Complex Elementary Functions, or Much Ado About Nothing's Sign Bit
in The State of the Art in Numerical Analysis, (eds. Iserles and Powell), Clarendon Press, Oxford, 1987.
A Wordsize- and Radix-Independent Standard for Floating-Point Arithmetic
(with W. J. Cody et al.), IEEE Micro, August 1984, pp. 86-100.
Mathematics Written in Sand
Proc. Joint Statistical Mtg. of the American Statistical Association, 1983, pp. 12-26.
(A legible reproduction is available below) (PDF file)
Norm-Preserving Dilations and Their Applications to Optimal Error Bounds
(with C. Davis and H. F. Weinberger), SIAM J. Numerical Analysis, Vol. 19, 1982, pp. 445-469.
Residual Bounds on Approximate Eigensystems of Nonnormal Matrices
(with B. N. Parlett and E. Liang), SIAM J. Numerical Analysis, Vol. 19, 1982, pp. 470-484.
A Family of Anadromic Numerical Methods for Matrix Riccati Differential Equations
(with Ren-Cang Li), Mathematics of Computation, Vol. 81 #227, Jan. 2012, pp. 233-265.
(PDF file)
Unconventional Schemes for a Class of Ordinary Differential Equations --
-- With Applications to the Korteweg-deVries Equation
(with Ren-Cang Li), J. Computational Physics, Vol. 134, 1997, pp. 316-331.
Composition Constants for Raising the Orders of Unconventional Schemes for Ordinary Differential Equations
(with Ren-Cang Li), Math. of Computation, Vol. 66, 1997, pp. 1089-1099.
Pinchings and Norms of Scaled Triangular Matrices
(with Ren-Cang Li & Rajendra Bhatia), Linear & Multilinear Algebra, Vol. 50, 2002, pp. 15-21.
Is there a small skew Cayley transform with zero diagonal ?
Linear Algebra and its Applications 417 (2006) pp. 335-341.
(A version with fewer misprints is available here:) (PDF file)
Error bounds from extra-precise iterative refinement (with J.W. Demmel et al.)
ACM Transactions on Mathematical Software (TOMS) archive 32, Issue 2 (June 2006) pp. 325 - 351
(PDF file)

Files available from this homepage, last updated 9 Aug. 2012

self-portrait thumbnail W. Kahan's self-portrait.

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