Large-scale unconstrained minimization
The method implemented in LBFGS is the limited-memory BFGS algorithm, as described Liu and Nocedal [1989]. It is intended for problems with many variables. In this method quasi-Newton corrections are stored in vector form; when the available storage is used up, the oldest correction is deleted to make space for a new one. The user specifies the number m of BFGS corrections that should be stored. LBFGS requires 2m(n+1)+4n storage locations.
The steplength is determined at each iteration by a line-search routine (supplied by J. Moré and D. Thuente) that enforces a sufficient decrease condition and a curvature condition.
LBFGS is written in Fortran 77. Single- and double-precision versions of the software are available. Machine dependencies are restricted to BLOCK DATA LB2.
LBFGS is also available in the Harwell Library under the name VA15.
Contact:
Jorge Nocedal Northwestern University Department of Electric Engineering and Computer Science Evanston, IL 60208 Phone: (708) 491-5038 E-Mail: nocedal@eecs.nwu.edu
D. C. Liu and J. Nocedal, On the limited memory BFGS method for large-scale optimization, Math. Programming 45 (1989), pp. 503--528.
J. Nocedal, Updating quasi-Newton matrices with limited storage, Math. Comp. 24 (1980), pp. 773--782.
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