/* D01RJ_T1W_F C++ Header Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 * Mark 27, 2019.
 */

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

extern "C"
{
  static void NAG_CALL f(void * &ad_handle,
                         const nagad_t1w_w_rtype x[],
                         const Integer &nx,
                         nagad_t1w_w_rtype fv[],
                         Integer &iflag,
                         Integer iuser[],
                         nagad_t1w_w_rtype ruser[],
                         const void *&cpuser);
}

int main(void)
{
  // Scalars
  int               exit_status = 0;

  cout << "D01RJ_T1W_F C++ Header Example Program Results\n\n";

  // The example function can raise various exceptions - it contains
  // a division by zero and a log singularity - although its integral
  // is well behaved.

  Integer exmode[3], exmode_old[3];
  nag_get_ieee_exception_mode(exmode_old);
  // Save the original halting mode.

  // Turn exception halting mode off for the three common exceptions.
  for (int i=0; i<3; i++) {
    exmode[i] = 0;
  }
  nag_set_ieee_exception_mode(exmode);
  
  double            pi = X01AAC;
  nagad_t1w_w_rtype a, b, epsabs, epsrel;
  a = 0.0;
  b = 2.0*pi;
  epsabs = 0.0;
  epsrel = 1.0e-4;
  
  Integer           maxsub = 20;
  Integer           lrinfo = 80;
  Integer           liinfo = 20;
  nagad_t1w_w_rtype *rinfo = 0;
  Integer           *iinfo = 0;
  
  rinfo = new nagad_t1w_w_rtype [lrinfo];
  iinfo = new Integer [liinfo];

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

  double            inc = 1.0, zero = 0.0;
  nagad_t1w_w_rtype result, abserr, ruser[2];
  Integer           iuser[1];
  const void        *cpuser = 0;
  iuser[0] = 0;
  ruser[0] = 4.0*pi*pi;
  ruser[1] = 30.0;
  
  // Call the AD routine with first active input derivative incremented
  nagad_t1w_inc_derivative(&ruser[0],inc);
  ifail = -1;
  d01rj_t1w_f_(ad_handle,f,a,b,epsabs,epsrel,maxsub,result,abserr,rinfo,iinfo,
               iuser,ruser,cpuser,ifail);
  nagad_t1w_set_derivative(&ruser[0],zero);
  if (ifail<0) {
    cout << "\n ** d01rj_t1w_f_ failed error exit ifail = " << ifail << endl;
    goto END;
  }
  // Print inputs and primal outputs.
  cout << "\n lower limit of integration (a) = " << nagad_t1w_get_value(a) << endl;
  cout << " upper limit of integration (b) = " << nagad_t1w_get_value(b) << endl;
  cout << " absolute accuracy requested    = " << nagad_t1w_get_value(epsabs) << endl;
  cout << " relative accuracy requested    = " << nagad_t1w_get_value(epsrel) << endl;
  cout << " maximum number of subintervals = " << maxsub << endl;
  cout.setf(ios::scientific,ios::floatfield);
  cout.precision(4);
  if (ifail >= 0) {
    cout << "\n approximation to the integral  : " << nagad_t1w_get_value(result) << endl;
    cout << " estimate of the absolute error : " << nagad_t1w_get_value(abserr) << endl;
    cout << " number of function evaluations : " << iinfo[0] << endl;
  }

  cout << "\n Derivatives calculated: First order tangents\n";
  cout << " Computational mode    : algorithmic\n";
  
  // Get derivatives
  double dr;
  dr = nagad_t1w_get_derivative(result);
  cout << "\n Derivative of solution w.r.t to parameter in ruser:\n";
  cout << " dI/druser[0] = " << dr << endl;

  
  nagad_t1w_inc_derivative(&ruser[1],inc);
  ifail = -1;
  d01rj_t1w_f_(ad_handle,f,a,b,epsabs,epsrel,maxsub,result,abserr,rinfo,iinfo,
               iuser,ruser,cpuser,ifail);
  dr = nagad_t1w_get_derivative(result);
  cout << " dI/druser[1] = " << dr << endl;

END:
  // Remove computational data object
  x10ab_t1w_f_(ad_handle,ifail);

  // Restore the original halting mode
  nag_set_ieee_exception_mode(exmode_old);
  
  delete [] rinfo;
  delete [] iinfo;
  return exit_status;
}

static void NAG_CALL f(void * &ad_handle,
                       const nagad_t1w_w_rtype x[],
                       const Integer &nx,
                       nagad_t1w_w_rtype fv[],
                       Integer &iflag,
                       Integer iuser[],
                       nagad_t1w_w_rtype ruser[],
                       const void *&cpuser)
{
  // dco/c++ used here to perform AD of the following
  nagad_t1w_w_rtype tmp1, tmp2;
  for (int i=0; i<nx; i++) {
    if (x[i] == 1.0) {
      iflag = -1;
      iuser[0] = iflag;
    } else {
      tmp1 = sqrt(1.0-x[i]*x[i]/ruser[0]);
      tmp2 = x[i]*sin(ruser[1]*x[i]);
      fv[i] = tmp2/tmp1;
    }
  }
  return;
}