/* F01FC_A1W_F C++ Header Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 * Mark 27, 2019.
 */

#include <dco_light.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 << "F01FC_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;
  Complex           *ac=0;
  nagad_a1w_w_rtype *ar=0, *ai=0;

  a    =  new nagad_a1w_w_ctype [n*n];  
  a_in =  new nagad_a1w_w_ctype [n*n];
  ar   =  new nagad_a1w_w_rtype [n*n];
  ai   =  new nagad_a1w_w_rtype [n*n];
  ac   =  new Complex           [n*n];
  
  // Create AD tape
  nagad_a1w_ir_create();

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

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

  // Find exp(A)
  ifail = 0;
  f01fc_a1w_f_(ad_handle,n,a,n,ifail);

  // Print exp(A)
  for (int i = 0; i<n; i++) {
    for (int j = 0; j<n; j++) {
      int k = i + j*n;
      
      ac[k].re = nagad_a1w_get_value(real(a[k]));
      ac[k].im = nagad_a1w_get_value(imag(a[k]));
    }
  }

  cout << endl;
  NagError  fail;
  INIT_FAIL(fail);
  x04dac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ac,n,
         "  Exp(A)",0,&fail);

  cout << "\n\n Derivatives calculated: First order adjoints\n";
  cout << " Computational mode    : algorithmic\n";
  cout << "\n Derivatives of diagional of exp(A) w.r.t diagonal of imag(A):\n";
  
  // Obtain derivatives
  for (int i=0; i<n; i++) {
    nagad_a1w_ir_zero_adjoints();
    double  inc = 1.0;
    Integer k = i*n+i;
    nagad_a1w_w_rtype avr;
    avr = real(a[k]);
    nagad_a1w_inc_derivative(&avr,inc);

    ifail = 0;
    nagad_a1w_ir_interpret_adjoint(ifail);
  
    for (int j=0; j<n; j++) {
      Integer l = j + j*n, p = i + j*n;
      double dd = nagad_a1w_get_derivative(ai[l]);
      ac[p].re = dd;
    }
    
    nagad_a1w_ir_zero_adjoints();
    nagad_a1w_w_rtype avi;
    avi = imag(a[k]);
    nagad_a1w_inc_derivative(&avi,inc);

    ifail = 0;
    nagad_a1w_ir_interpret_adjoint(ifail);
  
    for (int j=0; j<n; j++) {
      Integer l = j + j*n, p = i + j*n;
      double dd = nagad_a1w_get_derivative(ai[l]);
      ac[p].im = dd;
    }
  }

  // Print derivatives
  cout << endl;
  INIT_FAIL(fail);
  x04dac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ac,n,
         "     d(expA(i,i)/dImag(A(j,j))",0,&fail);

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

  return exit_status;
}