re used to solve 
% unconstrained nonlinear optimization problems. They are extensions of the
% conjugate gradient iterative method for solving linear systems adapted to
% solve unconstrained nonlinear optimization problems.
%
% The Poblano function for the nonlinear conjugate gradient methods is
% called |ncg|.
%%
%
% <html><hr></html>
%% Method Description
%
% The general steps of NCG methods are given below in high-level
% pseudo-code:
%%
%
% 
% $$
% \begin{tabular}{ll}
% \emph{1.} & Input: $x_0$, a star