A FORTRAN-90 CODE FOR UNCONSTRAINED NONLINEAR MINIMIZATION

This paper describes a Fortran 90 implementation of ACM Transactions o n Mathematical Software Algorithm 630, a minimization algorithm design ed for use in a limited-memory environment. It includes implementation of the Buckley-LeNir method, Nocedal's limited memory algorithm, and an experimental limited-memory implementation of a factored update due to Powell, as well as a fairly standard quasi-Newton implementation d ue originally to Shanno. This algorithm uses a number of the new featu res of Fortran 90 to offer capabilities that were not formerly availab le.