/* E01EA_T1W_F C++ Header Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 * Mark 27, 2019.
 */

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

int main(void)
{
  // Scalars
  int               exit_status = 0;
  
  cout << "E01EA_T1W_F C++ Header Example Program Results\n\n";

  // Skip first line of data file
  string mystr;
  getline (cin, mystr);
  // Read number of data points
  Integer n;
  cin >> n;

  // Allocate arrays for data and interpolant
  nagad_t1w_w_rtype *x = 0, *y = 0, *f = 0;
  Integer           *triang = 0;
  x      = new nagad_t1w_w_rtype [n];
  y      = new nagad_t1w_w_rtype [n];
  f      = new nagad_t1w_w_rtype [n];
  triang = new Integer           [7*n];

  // Create AD configuration data object
  Integer ifail = 0;
  void    *ad_handle = 0;
  x10aa_t1w_f_(ad_handle,ifail);

  // Read data and register variables
  for (int i=0; i<n; i++) {
    double xr, yr, fr;
    cin >> xr >> yr >> fr;
    x[i] = xr;
    y[i] = yr;
    f[i] = fr;
  }
    
  ifail = 0;
  e01ea_t1w_f_(n,x,y,triang,ifail);
  // Evaluate interpolant and derivatives at a mid-point
  nagad_t1w_w_rtype px[1], py[1], pf[1];
  double            xint, yint;
  xint = 0.5*(nagad_t1w_get_value(x[n/2-1]) + nagad_t1w_get_value(x[n/2]));
  yint = 0.5*(nagad_t1w_get_value(y[n/2-1]) + nagad_t1w_get_value(y[n/2]));
  px[0] = xint;
  py[0] = yint;

  // Call the AD routine
  double inc = 1.0, zero = 0.0;
  Integer     m = 1;
  nagad_t1w_inc_derivative(&px[0],inc);
  ifail = 0;
  e01eb_t1w_f_(ad_handle,m,n,x,y,f,triang,px,py,pf,ifail);
  double dx = nagad_t1w_get_derivative(pf[0]);
  nagad_t1w_set_derivative(&px[0],zero);

  nagad_t1w_inc_derivative(&py[0],inc);
  ifail = 0;
  e01eb_t1w_f_(ad_handle,m,n,x,y,f,triang,px,py,pf,ifail);
  double dy = nagad_t1w_get_derivative(pf[0]);

  cout << "\n Interpolant point: x = " << xint << " y = " << yint << endl;
  cout.precision(5);
  cout << " Interpolated value = " << nagad_t1w_get_value(pf[0]) << endl;

  cout << "\n Derivatives calculated: First order tangents\n";
  cout << " Computational mode    : algorithmic\n";
  
  cout.setf(ios::scientific,ios::floatfield);
  cout.precision(4);
  cout << "\n Derivatives of fitted value w.r.t. fit point:\n\n";
  cout << "     d/dx  = " << dx << endl;
  cout << "     d/dy  = " << dy << endl;

  // Remove computational data object
  x10ab_t1w_f_(ad_handle,ifail);
  
  delete [] x;
  delete [] y;
  delete [] f;
  delete [] triang;
  return exit_status;
}