James Weldon Demmel is an American mathematician and computer scientist, the Dr. Richard Carl Dehmel Distinguished Professor of Mathematics and Computer Science at the University of California,Berkeley.Demmel is known for his work on LAPACK, a software library for numerical linear algebra and more generally for research in numerical algorithms combining mathematical rigor with high performance implementation.Prometheus, a parallel multigrid finite element solver written by Demmel, Mark Adams, and Robert Taylor, won the Carl Benz Award at Supercomputing 1999 and the Gordon Bell Prize for Adams and his coworkers at Supercomputing 2004.He received Paris Kanellakis Award in 2014 for contributions to algorithms and software for numerical linear algebra used in scientific computing and large-scale data analysis.