/* F03BN_A1W_F C++ Header Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 * Mark 27, 2019.
 */

#include <dco.hpp>
#include <nag.h>
#include <nagx04.h>
#include <nagad.h>
#include <stdio.h>
#include <string>
#include <iostream>
using namespace std;

int main(void)
{
  int       exit_status = 0;
  void      *ad_handle = 0;
  Integer   ifail = 0;

  cout << "F03BN_A1W_F C++ Header Example Program Results\n\n";
  // Skip heading in data file
  string mystr;
  getline (cin, mystr);

  // Read problem size and number of right-hand-sides 
  Integer n;
  cin >> n;

  // Allocate arrays containing A and its factorized form, B
  // and the solution X.
  nagad_a1w_w_ctype *a=0, *a_in=0;
  nagad_a1w_w_rtype *a_r=0, *a_i=0;
  Complex           *ar=0;
  Integer           *ipiv=0;
  a    =  new nagad_a1w_w_ctype [n*n];  
  a_in =  new nagad_a1w_w_ctype [n*n];
  a_r  =  new nagad_a1w_w_rtype [n*n];
  a_i  =  new nagad_a1w_w_rtype [n*n];
  ipiv =  new Integer           [n];  
  ar   =  new Complex           [n*n];
  
  // Create AD tape
  nagad_a1w_ir_create();

  // Read the matrix A, register and copy
  double dr, di;
  Complex dc;
  for (int i = 0; i<n; ++i) {
    for (int j = 0; j<n; ++j) {
      cin >> dr >> di;
      Integer k = i + j*n;
      a_r[k] = dr;
      a_i[k] = di;
      nagad_a1w_ir_register_variable(&a_r[k]);
      nagad_a1w_ir_register_variable(&a_i[k]);
      a[k].real(a_r[k]);
      a[k].imag(a_i[k]);
      ar[k].re = dr;
      ar[k].im = di;
    }
  }

  // Print matrix A
  cout << endl;
  NagError  fail;
  INIT_FAIL(fail);
  x04dac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ar,n,
         "  A",0,&fail);

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

  // Factorize the matrix A
  ifail = 0;
  f07ar_a1w_f_(ad_handle,n,n,a,n,ipiv,ifail);

  // Print Factorization of A
  for (int i = 0; i<n; i++) {
    for (int j = 0; j<n; j++) {
      int k = i + j*n;
      
      nagad_a1w_w_rtype akr, aki;
      akr = real(a[k]);
      aki = imag(a[k]);
      ar[k].re = nagad_a1w_get_value(akr);
      ar[k].im = nagad_a1w_get_value(aki);
    }
  }
  cout << endl;
  // NagError  fail;
  INIT_FAIL(fail);
  x04dac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ar,n,
         "  Array A after factorization",0,&fail);

  nagad_a1w_w_ctype d;
  Integer           id[2];
  ifail = 0;
  f03bn_a1w_f_(ad_handle,n,a,n,ipiv,d,id,ifail);

  nagad_a1w_w_rtype dcr, dci;
  dcr = real(d);
  dci = imag(d);
  dr = nagad_a1w_get_value(dcr);
  di = nagad_a1w_get_value(dci);
  cout << " d = (" << dr << "," << di << ") id = ";
  cout << id[0] << ", " << id[1] << endl;
  dr = dr*pow(2.0,id[0]);
  di = di*pow(2.0,id[1]);
  cout << "\n value of determinant = (" << dr << "," << di << ")" << endl;

  cout << "\n\n Derivatives calculated: First order adjoints\n";
  cout << " Computational mode    : algorithmic\n";
  cout << "\n Derivatives of real(d) w.r.t A:\n";

  // Obtain derivatives
  double inc = 1.0;
  nagad_a1w_w_rtype dt;
  dt = real(d);
  nagad_a1w_inc_derivative(&dt,inc);
  ifail = 0;
  nagad_a1w_ir_interpret_adjoint(ifail);
  
  for (int i=0; i<n; i++) {
    for (int j=0; j<n; j++) {
      Integer k = i + j*n;
      double dr = nagad_a1w_get_derivative(a_r[k]);
      double di = nagad_a1w_get_derivative(a_i[k]);
      ar[k].re = dr;
      ar[k].im = di;
    }
  }

  // Print derivatives
  cout << endl;
  INIT_FAIL(fail);
  x04dac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ar,n,
         "           d(dreal)/da(i,j)",0,&fail);

 END:
  // Remove computational data object and tape
  ifail = 0;
  x10ab_a1w_f_(ad_handle,ifail);
  nagad_a1w_ir_remove();

  return exit_status;
}