Remembering G.W. “Pete” Stewart (1940-2026)

G.W. “Pete” Stewart, a former faculty member in the University of Maryland Department of Computer Science whose work focused on numerical linear algebra and mathematical software, passed away on June 9, 2026. 

Stewart joined UMD in 1974 and remained a full-time professor until his retirement in 2008. In addition to the Department of Computer Science, he held appointments in the Applied Mathematics Program, the Institute for Physical Science and Technology and the University of Maryland Institute for Advanced Computer Studies. After retiring, he continued to be involved in research with the department and was named Distinguished University Professor Emeritus.

Stewart received his bachelor’s and doctoral degrees from the University of Tennessee. Before coming to UMD, he taught at the University of Texas at Austin and Carnegie Mellon University.

His research centered on matrix computations, including matrix decompositions, least squares problems, eigenvalue problems, singular value decomposition and perturbation theory. These areas are part of the numerical methods used in scientific computing, engineering analysis and applied mathematics.

Stewart was one of the developers of LINPACK, a portable software package for dense matrix computations. The project, developed with Cleve Moler, Jim Bunch and later Jack Dongarra, was built on basic linear algebra subprograms that could be adapted for different computer architectures. LINPACK became a standard tool for solving systems of linear equations and computing matrix decompositions, and its benchmark codes were used for years to evaluate computer performance.

Stewart authored eight books and more than 170 articles, and he supervised six doctoral students. His books covered matrix decompositions, perturbation theory and numerical methods. He also had an interest in the history of mathematics and translated works by Carl Friedrich Gauss on least squares from Latin and German into English, adding commentary.

Stewart is survived by his wife, Astrid Schmidt-Nielsen; his children, Michael and Laura; and his stepchildren, Mimi and Tom.

—Text adapted from a news brief by SIAM