message: added HagerZhang line search to steepest descent example
diff: @@ -16,6 +16,7 @@ extern crate argmin_derive;
  use argmin::prelude::*;
  use argmin::solver::gradientdescent::*;
  // use argmin::solver::linesearch::BacktrackingLineSearch;
  +use argmin::solver::linesearch::HagerZhangLineSearch;
  use argmin::solver::linesearch::MoreThuenteLineSearch;
  use argmin::testfunctions::{rosenbrock_2d, rosenbrock_2d_derivative};
  @@ -39,14 +40,15 @@ fn run() -> Result<(), Error> {
  let cost = MyProblem {};
  // definie inital parameter vector
  - // let init_param: Vec<f64> = vec![1.2, 1.2];
  - let init_param: Vec<f64> = vec![-1.2, 1.0];
  + let init_param: Vec<f64> = vec![1.2, 1.2];
  + // let init_param: Vec<f64> = vec![-1.2, 1.0];
  - let mut linesearch = MoreThuenteLineSearch::new(Box::new(cost.clone()));
  + // let mut linesearch = MoreThuenteLineSearch::new(Box::new(cost.clone()));
  + let mut linesearch = HagerZhangLineSearch::new(Box::new(cost.clone()));
  // let mut linesearch = BacktrackingLineSearch::new(Box::new(cost.clone()));
  linesearch.set_initial_alpha(1.0)?;
  // linesearch.set_initial_alpha(10.0)?;
  - linesearch.set_max_iters(10);
  + linesearch.set_max_iters(200);
  // linesearch.set_rho(0.5);
  let iters = 10000;
  