/* E04DG_P0W_F C++ Header Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 * Mark 27, 2019.
 */

#include <nag.h>
#include <nagad.h>
#include <stdio.h>
#include <math.h>
#include <nagx02.h>
#include <string>
#include <iostream>
using namespace std;

extern "C"
{
  static void NAG_CALL objfun(void* &ad_handle, Integer &mode,
                              const Integer &n, const double x[],
                              double &objf, double objgrd[],
                              const Integer &nstate, Integer iuser[],
                              double ruser[]);
}

int main(void)
{
  int     exit_status = 0;
  double  objf;
  cout << "E04DG_P0W_F C++ Header Example Program Results\n\n";

  Integer ifail = 0;
  void    *ad_handle = 0;

  // Read problem parameters and register for differentiation
  // Skip first line of data file
  string mystr;
  getline (cin, mystr);

  Integer n;
  cin >> n;
  
  // passive routine fixed length array arguments
  Integer        iuser[1], iwsav[610];
  double         ruser[1], rwsav[475];
  char           cwsav[1];
  logical        lwsav[120];
  const Charlen  name_l = 6, cwsav_l = 1;

  // passive routine variable length arrays 
  Integer        *iwork = 0;
  double         *x = 0, *x_in = 0, *objgrd = 0, *work = 0;

  iwork  = new Integer [n+1];
  x      = new double  [n];
  x_in   = new double  [n];
  objgrd = new double  [n];
  work   = new double  [13*n];
  
  for (int i=0; i<n; i++) {
    cin >> x[i];
  }

  // Initialize sav arrays
  ifail = 0;
  e04wb_p0w_f_("E04DGA",cwsav,1,lwsav,120,iwsav,610,rwsav,475,ifail,name_l,
               cwsav_l);

  // Solve the problem
  Integer iter;
  ifail = 0;
  e04dg_p0w_f_(ad_handle,n,objfun,iter,objf,objgrd,x,iwork,work,iuser,
               ruser,lwsav,iwsav,rwsav,ifail);

  // Primal results
  cout.setf(ios::scientific,ios::floatfield);
  cout.precision(3);
  cout << "\n Objective value = ";
  cout.width(12); cout << objf;
  cout << "\n Solution point  = ";
  for (int i=0; i<n; i++) {
    cout.width(12); cout << x[i];
  }

  cout << "\n Estim gradient  = ";
  for (int i=0; i<n; i++) {
    cout.width(12); cout << objgrd[i];
  }

  delete [] iwork;
  delete [] x;
  delete [] x_in;
  delete [] objgrd;
  delete [] work;
  return exit_status;
}

static void NAG_CALL objfun(void* &ad_handle, Integer &mode,
                            const Integer &n, const double x[],
                            double &objf, double objgrd[],
                            const Integer &nstate, Integer iuser[],
                            double ruser[])
{
  
  double  x1, x2, y1, y2, expx1;
  
  x1 = x[0];
  x2 = x[1];
  expx1 = exp(x1);
  y1 = 2.0*x1;
  y1 = y1 + x2;
  y2 = x2 + 1.0;
  x1 = y1*y1;
  x2 = y2*y2;
  x1 = x1 + x2;
  objf = expx1*x1;
  
  if (mode==2) {
    y2 = y1 + y2;
    y2 = 2.0*y2;
    y1 = 4.0*y1;
    y1 = expx1*y1;
    objgrd[0] = y1 + objf;
    objgrd[1] = expx1*y2;
  }
  
  return;
}