/* C05QD_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 <nagx04.h>
#include <iostream>
#include <string>
using namespace std;

int main (void)
{
  // Scalars
  int               exit_status = 0;
  const Integer     mode = 2, n = 7;

  cout << "C05QD_P0W_F C++ Header Example Program Results\n\n";

  // problem parameters and starting value
  double            ruser[5], x[7];

  ruser[0] = -1.0;
  ruser[1] =  3.0;
  ruser[2] = -2.0;
  ruser[3] = -2.0;
  ruser[4] = -1.0;

  for (int i=0; i<n; ++i) {
    x[i] = -1.0;
  }

  Integer ifail = 0;
  void    *ad_handle = 0;
  double diag[n], epsfcn, fjac[n*n], factor, fvec[n],
                    qtf[n], r[n*(n+1)/2], rwsav[4*n+10], xtol;
  Integer           irevcm, iwsav[17], ml, mu;

  xtol = sqrt(X02AJC);
  factor = 100.;
  for (int i=0; i<n; ++i) {
    diag[i] = 1.;
  }
  ml = 1;
  mu = 1;
  epsfcn = 0.;

  irevcm = 0;

  do {
    ifail = 0;
    c05qd_p0w_f_(ad_handle,irevcm,n,x,fvec,xtol,ml,mu,epsfcn,mode,
                 diag,factor,fjac,r,qtf,iwsav,rwsav,ifail);

    switch (irevcm) {
    case 1:
      // Monitoring exit
      continue;
    case 2:
      for (int i=0; i<n; ++i) {
        fvec[i] = (ruser[1] + ruser[2]*x[i])*x[i] - ruser[4];
      }
      for (int i=1; i<n; ++i) {
        fvec[i] = fvec[i] + ruser[0]*x[i-1];
      }
      for (int i=0; i<n-1; ++i) {
        fvec[i] = fvec[i] + ruser[3]*x[i+1];
      }
      break;
    }

  } while (irevcm != 0);

  cout.setf(ios::scientific,ios::floatfield);
  cout.precision(4);
  cout << "           Solution:\n";
  for (int i=0; i<n; ++i) {
    cout.width(10);
    cout << i+1;
    cout.width(20);
    cout << x[i] << endl;
  }

  return exit_status;
}