snitch_all.hpp is the only header required to use the library; other headers may be provided for convenience functions (e.g., reporters for common CI frameworks) and these must still be included ...

Only one header file "lbfgs.hpp" is all you need. The library implements Limited-Memory Broyden-Fletcher-Goldfarb-Shanno Method (L-BFGS). A highly robust line search proposed by Lewis and Overton has ...