/* F01EC_T1W_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;
  NagError  fail;
  INIT_FAIL(fail);

  cout << "F01EC_T1W_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_t1w_w_rtype *a=0, *a_in=0;
  double            *ar=0;

  a    =  new nagad_t1w_w_rtype [n*n];  
  a_in =  new nagad_t1w_w_rtype [n*n];
  ar   =  new double            [n*n];
  
  // Read the matrix A, register and copy
  double dd;
  for (int i = 0; i<n; ++i) {
    for (int j = 0; j<n; ++j) {
      cin >> dd;
      Integer k = i + j*n;
      a_in[k] = dd;
    }
  }

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

  for (int i=0; i<n; ++i) {
    {
      double  inc = 1.0;
      Integer k = i*n+i;
      nagad_t1w_inc_derivative(&a_in[k],inc);
    }
    for (int j = 0; j<n*n; ++j) {
      a[j] = a_in[j];
    }
    // Find exp(A)
    ifail = 0;
    f01ec_t1w_f_(ad_handle,n,a,n,ifail);

    if (i==0) {
      // Print exp(A)
      for (int j = 0; j<n*n; j++) {
	ar[j] = nagad_t1w_get_value(a[j]);
      }

      cout << endl;
      x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ar,n,
	     "  Exp(A)",0,&fail);
    }
    
    for (int j=0; j<n; j++) {
      Integer l = j + j*n, p = i*n + j;
      double dd = nagad_t1w_get_derivative(a[l]);
      ar[p] = dd;
    }
    {
      double  zero = 0.0;
      Integer k = i*n+i;
      nagad_t1w_set_derivative(&a_in[k],zero);
    }
  }
  
  cout << "\n\n Derivatives calculated: First order tangents\n";
  cout << " Computational mode    : algorithmic\n";
  cout << "\n Derivatives of diagonal of exp(A) w.r.t diagonal of A:\n";
  
  // Print derivatives
  cout << endl;
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,n,ar,n,
         "     d(expA(i,i)/dA(j,j)",0,&fail);

  // Remove computational data object
  ifail = 0;
  x10ab_t1w_f_(ad_handle,ifail);

  delete [] a;
  delete [] a_in;
  delete [] ar;
  
  return exit_status;
}