“…The most important is the use of the spectral steplength choice, also known as the BarzilaiBorwein choice, ( [2,13,17,22]) that has proved to yield fast local convergence for the solution of nonlinear optimization problems ( [4,5,6,15,23]). However, this special choice of step size cannot guarantee global convergence by itself, as it usually happens with other variations (see, e.g., [7,11,12,24,26]). For that, we combine its use with a tolerant globalization strategy, that represents the second new feature.…”