Charles Broyden, Roger Fletcher, Donald Goldfarb and David Shanno

Alphabetically and from left to right, Charles Broyden, Roger Fletcher, Donald Goldfarb and David Shanno, for whom the BFGS nonlinear optimization update step is named, at the NATO Advanced Research Institute on Nonlinear Optimization, Cambridge University, in Cambridge, England, July 1981. (photo provided by Richard Cottle.)