Modifications to a classic BFGS library for use with SIMD-equipped hardware and an AAD library

Abstract

We introduce certain modifications of the BFGS method for functions that are not parallelizable by nature (having consecutive operations only) taking advantage of SIMD. We also provide a modified LBFGS\texttt{++} library that takes advantage of these modifications, and the use of AAD, and give an interface for AAD users that takes advantage of the modified library automatically. We give two examples to illustrate the performance. The modified library is up to 3.8 times faster for European Swaption curve calibration in ORE (not parallelizable) and 1.4 times faster for calibrating the LMM model by a set of European options.