lbfgs is an implementation of the L-BFGS algorithm [1]
to solve unconstrained minimization problems via a limited-memory quasi-Newton (BFGS) algorithm.
It is called a limited-memory method because a low-rank approximation of the
Hessian matrix inverse is stored instead of the entire Hessian inverse.
The program was originally written in Fortran [2] by Jorge Nocedal,
incorporating some functions originally written by Jorge J. Moré and David J. Thuente,
and translated into Lisp automatically via the program f2cl.
The Maxima package lbfgs comprises the translated code plus
an interface function which manages some details.
References:
[1] D. Liu and J. Nocedal. "On the limited memory BFGS method for large scale optimization". Mathematical Programming B 45:503–528 (1989)