L-BFGS-B is a hugely popular algorithm for box-constrained minimisation and the best implementation is still in Fortran. This is commonly used in machine learni

L-BFGS-B is a hugely popular algorithm for box-constrained minimisation and the best implementation is still in Fortran. This is commonly used in machine learning. Things like scipy.optimize.fmin_l_bfgs_b are just wrappers for the Fortran code.