Velvel Kahan

Velvel Kahan’s casual identify in Yiddish, װעלװעל, means “little wolf.” If he wants a extra formal identify, Velvel makes use of William.

Contents

First Assembly

I first met Velvel in George Forsythe’s workplace at Stanford in 1962. Velvel had come to California from Toronto for a gathering of the IBM laptop customers group, SHARE, and visited Stanford on his method.

When Forsythe launched us, Velvel stated, “Oh, Cleve Moler, I’ve needed to see you. Do you’ve got a minute?” We went to my workplace and Velvel requested “Do you’ve got a replica of the report you wrote at JPL final summer time?” I retrieved the report from my meager assortment. Velvel opened it to web page 12, pointed to an equation, and stated

        "That is flawed."

He was proper.

Nameless Referee

I submitted the manuscript for my first paper, “Iterative Refinement in Floating Level”, to the Journal of the ACM in 1966. Forsythe was the editor who dealt with the submission. He despatched it to an nameless referee

The manuscript was 10 pages lengthy. The referee’s report was 12. Guess who refereed the paper.

Shut sufficient

In 1968, Velvel was pondering of leaving the College of Toronto. Forsythe instructed me he thought-about providing Kahan a place at Stanford, however he was afraid Velvel can be too disruptive. “I hope he involves Berkeley,” George stated. “That is shut sufficient.”

Velvel Kahan, 1968. (Photograph Credit score: George M. Bergman, Archives of the Mathematisches Forschungsinstitut Oberwolfach.)

Householder VII

I at all times met Velvel at Householder seminars. In 1977, the Householder seminar was at Asilomar, a California state park south of Monterey.

Velvel would start talks in regards to the significance of dependable floating-point arithmetic with a narrative that went one thing like this.

A doctor leaves Sacramento late one night. He flies his
personal airplane dwelling to Santa Barbara. After setting the autopilot,
he falls asleep. When the airplane is over the mountains north of the
airport, the autopilot fails with a floating-point overflow and
the airplane crashes. The physician’s property sues you as a result of your organization
wrote the autopilot software program.

This picture reveals Velvel telling that story with an overhead projector.

Householder XVII

In 1993, the Householder seminar was in California once more, this time at Lake Tahoe. Here’s a uncommon second when Velvel is definitely listening to me.

The Workplace

Each Velvel and Beresford Parlett have been on the college at U. C. Berkeley since 1968. Velvel’s pupil, Jerome Coonen, took this picture when he volunteered to assist filter Velvel’s workplace.

Turing Award

The quotation for Velvel’s Turing Award in 1989 reads:

For his basic contributions to numerical evaluation.
One of many foremost consultants on floating-point computations.
Kahan has devoted himself to “making the world secure for numerical
computations!”

https://amturing.acm.org/award_winners/kahan_1023746.cfm

IEEE 754

My buddy Axel Ruhe was from Sweden. He as soon as requested me the place he ought to go to on his first journey to the western United States. I really helpful

The conferences of the IEEE floating-point committee have been legendary. They might go on for hours at numerous spots in Silicon Valey. Affected by jetlag, Axel went to sleep on the ground of the convention room.

Right here is Velvel, remembering the committee. https://www.youtube.com/watch?v=ATCpecsyPE8.

Photograph Credit score: Alaina G. Levine, Heidelberg Laureate Discussion board.

Bibliography

Nelson Beebe has compiled this bibliography.

Oral Historical past

The manuscript of Thomas Haigh’s interview of Velvel in 2005 for SIAM’s oral historical past undertaking is 229 pages lengthy. Have a look. https://historical past.siam.org/oralhistories/kahan.htm.

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