By Matt Schudel

Washington Post Staff Writer

Wednesday, March 25, 2009

John W. Wrench Jr., 97, a retired mathematician with the Navy's Applied Mathematics Laboratory who once set a record by calculating the value of pi to more than 100,000 digits, died Feb. 27 of pneumonia at Northampton Manor Health Care Center in Frederick.

Before the use of computers became widespread, Dr. Wrench had an international reputation for computation. He later became a pioneer in the use of computers for mathematical calculations.

He came to Washington in 1939 to teach at George Washington University but spent most of his career doing theoretical research and developing high-speed computational methods for the Navy Department.

During World War II, he did classified research for the National Defense Research Council under contract at GWU and Catholic University. From 1945 to 1953, while working for the Navy, he worked on secret projects concerning the movement of underwater sound waves and the response of structures to underwater explosions.

In 1953, Dr. Wrench became deputy head of the applied mathematics laboratory at the Navy's David W. Taylor Model Basin at Carderock. He developed high-speed numerical methods for use in structural design, hydrodynamics, aerodynamics and data analysis. He became head of the laboratory about two years before he retired in 1974.

Dr. Wrench had long been fascinated by the mathematical concept of pi. In 1948, he and fellow mathematician Levi Smith used a primitive gear-driven calculating device to compute the value of pi to more than 1,000 digits. In 1961, Dr. Wrench and Daniel Shanks used an IBM 7090 computer to calculate pi to 100,265 places. They presented their printout to the Smithsonian Institution, and their feat was recognized in the Guinness Book of Records. With more advanced computers, the value of pi has been calculated to more than 1 trillion digits.

John William Wrench Jr. was born in Westfield, N.Y., and was a summa cum laude graduate of what is now the State University of New York at Buffalo. He received master's and doctoral degrees in mathematics from Yale University in 1935 and 1938, respectively.

Before coming to Washington, Dr. Wrench had faculty postings at Yale and Wesleyan University in Connecticut. While working for the Navy, he had brief faculty appointments at the University of Maryland and American University.

Dr. Wrench was a member of many professional societies and was a fellow of the Washington Academy of Sciences. He published more than 150 scientific papers. His wife said he wrote exclusively with a pen, even when he was doing complicated mathematical computations.

His interests included crossword puzzles, playing the piano and building elaborate dollhouses. In 1968, he hiked the length of the C&O Canal.

He was a Potomac resident before retiring to Frederick in 1974.

Survivors include his wife of 65 years, Constance Philpitt Wrench of Frederick; a daughter, Paula W. Weston of Sheridan, Wyo.; two sisters; a brother; two granddaughters; six great-grandchildren; and two great-great-grandchildren.

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