/* D01PA_A1W_F C++ Header Example Program.
 *
 * Copyright 2017 Numerical Algorithms Group.
 * Mark 26.2, 2017.
 */

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

extern "C"
{
  static void NAG_CALL functn(void* &ad_handle,
                              const Integer& ndim,
                              const nagad_a1w_w_rtype x[],
                              nagad_a1w_w_rtype& ret,
                              Integer iuser[],
                              nagad_a1w_w_rtype ruser[]);
}

int main(void)
{
  // Scalars
  int               exit_status = 0;
  Integer           mxord = 5, ndim = 3, sdvert = 8, ldvert = 4;

  cout << "D01PA_A1W_F C++ Header Example Program Results\n\n";

  // Allocate memory
  nagad_a1w_w_rtype *finvls = 0, *vert = 0, *vert_in = 0;
  if (!(finvls = NAG_ALLOC(mxord, nagad_a1w_w_rtype)) ||
      !(vert = NAG_ALLOC(ldvert*sdvert, nagad_a1w_w_rtype)) ||
      !(vert_in = NAG_ALLOC(ldvert*ndim, nagad_a1w_w_rtype))) {
    cout << "Allocation failure\n";
    exit_status = -1;
  } else {

    for (int i=0;i<ndim*ldvert;i++) {
      vert_in[i] = 0.0;
    }
    for (int i=1;i<ndim*ldvert;i=i+ldvert+1) {
      vert_in[i] = 1.0;
    }

    // Create AD tape
    nagad_a1w_ir_create();

    // Create AD configuration data object
    Integer ifail = 0;
    void    *ad_handle = 0;
    x10aa_a1w_f_(ad_handle,ifail);

    /* Register variables to differentiate w.r.t. */
    for (int i = 0; i < ndim*ldvert; i++) {
      nagad_a1w_ir_register_variable(&vert_in[i]);
    }
    
    for (int i=0;i<ndim*ldvert;i++) {
      vert[i] = vert_in[i];
    }
    
    cout << "\n Maxord   Estimated      Estimated         Integrand\n";
    cout << "           value         accuracy        evaluations\n";
    cout.setf(ios::scientific,ios::floatfield);
    cout.precision(4);
    Integer minord = 0, nevals = 1;
    for (Integer maxord = 1; maxord<=mxord; maxord++) {
      
      // Call the AD routine
      nagad_a1w_w_rtype esterr, ruser[1];
      Integer           iuser[1];
      ifail = 0;
      d01pa_a1w_f_(ad_handle,ndim,vert,ldvert,sdvert,functn,minord,
                  maxord,finvls,esterr,iuser,ruser,ifail);
      double finv_r = nagad_a1w_get_value(finvls[maxord-1]);
      double estr_r = nagad_a1w_get_value(esterr);
      cout.width(5); cout << maxord;
      cout.width(15); cout << finv_r;
      cout.width(15); cout << estr_r;
      cout.width(12); cout << nevals << endl;
      
      nevals = (nevals*(maxord+ndim+1))/maxord;
    }

    cout << "\n Derivatives calculated: First order adjoints\n";
    cout << " Computational mode    : algorithmic\n";

    // Get derivatives
    double inc = 1.0;
    nagad_a1w_w_rtype sol = finvls[mxord-1];
    
    nagad_a1w_inc_derivative(&sol,inc);
    nagad_a1w_ir_interpret_adjoint(ifail);

    cout.setf(ios::right);
    cout.precision(4);
    cout << "\n Solution, I = ";
    double ans_value = nagad_a1w_get_value(finvls[mxord-1]);
    cout.width(12); cout << ans_value << endl;
    cout << "\n Derivatives w.r.t vertices:\n";
    cout << "   i   j    d/dv(i,j)\n";

    cout.setf(ios::scientific,ios::floatfield);

    int k = -1;
    for (int i = 1; i <= ndim+1; i++) {
      for (int j = 1; j <= ndim; j++) {
        k = k + 1;
        double dfdv = nagad_a1w_get_derivative(vert_in[k]);
      
        cout.width(4); cout << i;
        cout.width(4); cout << j;
        cout.width(14); cout << dfdv << endl;
      }
    }

    // Remove computational data object and tape
    x10ab_a1w_f_(ad_handle,ifail);
    nagad_a1w_ir_remove();
  }

  NAG_FREE(vert);
  NAG_FREE(vert_in);
  NAG_FREE(finvls);

  return exit_status;
}
static void NAG_CALL functn(void* &ad_handle,
                            const Integer& ndim,
                            const nagad_a1w_w_rtype x[],
                            nagad_a1w_w_rtype& ret,
                            Integer iuser[],
                            nagad_a1w_w_rtype ruser[])
{
  // dco/c++ used here to perform AD of the following 
  ret = exp(x[0] + x[1] + x[2])*cos(x[0] + x[1] + x[2]);
  return;
}