The following input data should be provided to run SECANT METHOD (for unconstrained minimization).

A. In main Program:

  1. n  - number of variables

  2. nbundle - the maximum number of subgradients or discrete
  gradients which can be calculated at each iteration

  3. The parameter: ngradient.  

  This parameter is 0 (ngradient = 0) is subgradients of the objective
  function are not available. In this case subgradients are
  approximated using the values of the objective function. ngradient =
  1 if subgradients of the objective function are available (for
  example, for maximum function they can be calculated explicitly.

  4. Starting point: x0

B. In Subroutine FUNC the objective function is described

C. In Subroutine GRADIENT subgradients of the objective function are
calculted (It will called if ngradient = 1 in Main Program).

The rest of the source code should not be changed.

The code generates one output file: RESULTS.TXT. It contains the following information:
    1. The value of the objective function at the starting point;
    2. The value of the objective function at the solution;
    3. The number of the objective function evaluations;
    4. The number of subgradient evaluations;
    5. CPU time
