/* S15AD_A1W_F C++ Header Example Program.
 *
 * Copyright 2022 Numerical Algorithms Group.
 * Mark 28.4, 2022.
 */

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

int main()
{
  int exit_status = 0;

  // Input and output variables
  nagad_a1w_w_rtype e, x;

  cout << "S15AD_A1W_F C++ Header Example Program Results\n\n";

  // Create AD tape
  dco::ga1s<double>::global_tape = dco::ga1s<double>::tape_t::create();

  x = -1.;

  // Create AD configuration data object
  nag::ad::handle_t ad_handle;

  cout << "       x         erfc(x)   derfc/dx\n";
  cout.setf(ios::scientific, ios::floatfield);
  cout.setf(ios::right);
  cout.precision(4);

  // Register x, i.e. differentiate w.r.t. x
  dco::ga1s<double>::global_tape->register_variable(x);

  // Call NAG AD Routine
  Integer ifail = 0;
  nag::ad::s15ad(ad_handle, x, e, ifail);

  // Reset adjoints, increment e, and evaluate adjoint of erfc w.r.t. x
  dco::ga1s<double>::global_tape->zero_adjoints();
  double inc = 1.0;
  dco::derivative(e) += inc;
  ifail                                              = 0;
  dco::ga1s<double>::global_tape->sparse_interpret() = true;
  dco::ga1s<double>::global_tape->interpret_adjoint();

  // Get derivative, derfcdx and output values
  double dedx;
  dedx = dco::derivative(x);

  cout.width(12);
  cout << dco::value(x);
  cout.width(12);
  cout << dco::value(e);
  cout.width(12);
  cout << dedx << endl;

  dco::ga1s<double>::tape_t::remove(dco::ga1s<double>::global_tape);

  return exit_status;
}