Dr James Hardy Wilkinson, FRS, who made an outstanding contribution to computing through his work on numerical analysis, died on October 5. He was 67.

Born on September 27, 1919, he was educated at Sir Joseph Williamson's Mathematical School, Rochester, and Trinity College, Cambridge, where, at the age of 16, he won a major scholarship in mathematics. He went on to gain first class honours in Part II of the Maths Tripos and a distinction in Part III.

He entered the Ministry of Supply in 1940, in an outstation of the armament research department at the Mathematical Laboratory, Cambridge. He transferred in 1943 to Fort Halstead where he was involved in solving day-to-day problems in ballistics and the thermodynamics of explosives by classical mathematical techniques and by numerical methods.

After the war he joined the National Physical Laboratory (NPL) to embark on the work which subsequently led to world-wide recognition and acclaim.

He played a key part in developing the ACE computer, one of the first to be built. He then concentrated on the application of computers for solving scientific problems, developing the numerical methods needed for the task. In this research, Wilkinson departed from existing approaches and devised a new type of analysis based on a different philosophy.

This Wilkinson called 'backwards error analysis'. In trying to find a numerical solution to a mathematical problem, he found himself solving not the original problem but another close to it. From this he then worked backwards to solving the initial problem.

He published *Rounding Errors in Algebraic Processes* and* The Algebraic Eigenvalue Problem*, both standard works. He also developed mathematical software in high-level languages, the most common of which is Fortran (formula translation).

Following his retirement from NPL he was appointed professor in the computer science department at Stanford University, California.

Wilkinson, despite the many honours bestowed upon him, never lost contact with those around him, nor adopted an ostentatious life-style. The bicycle remained his preferred form of transport, and at many international gatherings his numerous foreign admirers were surprised to see him arrive on two wheels. His zest for fine wines, good food and convival company was shown in the numerous parties that he and his wife gave for friends and colleagues.

He married, in 1945, Heather Ware, who was a continuous support to him. She and their son survive him, a daughter having predeceased him.

Copyright (C) The Times, 1986