Fix (10 May 1939 – 10 March 2002) was an American mathematician who collaborated on several seminal papers and books in the field of finite element method.

In addition to his work in mathematics, Fix was a beer and homebrewing enthusiast and educator, as well as the author of several books about brewing.

[1] While there, he met Gilbert Strang, and collaborated with him on a paper regarding the Fourier analysis of finite element methods (FEM).

[1] In 1973, he and Strang published An Analysis of the Finite Element Method, a book that gave the latest advances in FEM "publicity and respectability".

[2] (Max Gunzburger of Iowa State University called it "one of the most important and influential applied mathematics books ever published.