William B. Gragg (1936–2016) ended his career as an emeritus professor in the Department of Applied Mathematics at the
Naval Postgraduate School
The Naval Postgraduate School (NPS) is a public graduate school operated by the United States Navy and located in Monterey, California.
It offers master’s and doctoral degrees in more than 70 fields of study to the U.S. Armed Forces, DOD ci ...
. He has made fundamental contributions in
numerical analysis, particularly the areas of
numerical linear algebra and
numerical methods for ordinary differential equations.
He received his PhD at
UCLA in 1964 under the direction of
Peter Henrici
Peter Henrici (born 31 March 1928) is a Swiss Jesuit priest, Blondelian philosopher and professor (1960–1993) at the Gregorian University. He was Auxiliary Bishop of Chur from 1993 to 2007.
Biography
Born on 31 March 1928 at Zurich, Henrici ...
. His dissertation work resulted in the
Gragg Extrapolation method for the numerical solution of
ordinary differential equations
In mathematics, an ordinary differential equation (ODE) is a differential equation whose unknown(s) consists of one (or more) function(s) of one variable and involves the derivatives of those functions. The term ''ordinary'' is used in contrast w ...
(sometimes also called the
Bulirsch–Stoer algorithm In numerical analysis, the Bulirsch–Stoer algorithm is a method for the numerical solution of ordinary differential equations which combines three powerful ideas: Richardson extrapolation, the use of rational function extrapolation in Richardson- ...
).
Gragg is also well known for his work on the
QR algorithm for
unitary
Unitary may refer to:
Mathematics
* Unitary divisor
* Unitary element
* Unitary group
* Unitary matrix
* Unitary morphism
* Unitary operator
* Unitary transformation
* Unitary representation
* Unitarity (physics)
* ''E''-unitary inverse semigroup ...
Hessenberg matrices, on updating the
QR factorization
In linear algebra, a QR decomposition, also known as a QR factorization or QU factorization, is a decomposition of a matrix ''A'' into a product ''A'' = ''QR'' of an orthogonal matrix ''Q'' and an upper triangular matrix ''R''. QR decomp ...
,
superfast solution of
Toeplitz systems, parallel algorithms for solving eigenvalue problems, as well as his exposition on the
Pade table
Pade is a village in Hsawlaw Township in Myitkyina District in the Kachin State of north-eastern Burma.Maplandia world gazetteer
References
External linksSatellite map at Maplandia.com
Populated places in Kachin State
Hsawlaw Township
...
and its relation to a large number of algorithms in
numerical analysis.
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References
External links
*
{{DEFAULTSORT:Gragg, William
1936 births
2016 deaths
20th-century American mathematicians
21st-century American mathematicians
Numerical analysts
People from Bakersfield, California