Walter Edwin Arnoldi (New York, December 14, 1917-October 5, 1995) was an American engineer known his Arnoldi iteration, an eigenvalue algorithm used in iteration in numerical linear algebra. Arnoldi graduated in mechanical engineering at the Stevens Institute of Technology in 1937 and attended a Master of Science course at Harvard. He worked at United Aircraft Corp. from 1939 to 1977. His main research interests included modelling vibrations, acoustics and aerodynamics of aircraft propellers. His 1951 paper The principle of minimized iterations in the solution of the eigenvalue problem is one of the most cited papers in numerical linear algebra.[1]