/* F08AH_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>
#include <string>
using namespace std;

// typedef DCO_TYPE nagad_t1w_w_rtype
typedef double DCO_BASE_TYPE;
typedef dco::gt1s<DCO_BASE_TYPE> DCO_MODE;
typedef DCO_MODE::type DCO_TYPE;

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

  cout << "F08AH_T1W_F C++ Header Example Program Results\n\n";

  // Create handle
  void    *ad_handle = 0;
  Integer ifail = 0;
  x10aa_t1w_f_(ad_handle,ifail);

  // Skip heading in data file
  string mystr;
  getline (cin, mystr);
  
  Integer m, n;
  cin >> m; cin >> n;

  Integer pda = m;
  Integer lwork = 64 * n;

  Integer tau_len;
  if (m<n) {
    tau_len = m;
  } else {
    tau_len = n;
  }

  // Allocate arrays
  // nagad_t1w_w_rtype *a = 0, *tau = 0, *a_in = 0, *work = 0;
  DCO_TYPE             *a = 0, *tau = 0, *work = 0, *a_in = 0;
  double               *l = 0, *dlda = 0;
  a    = new DCO_TYPE [m * n];
  work = new DCO_TYPE [lwork];
  a_in = new DCO_TYPE [m * n];
  tau  = new DCO_TYPE[tau_len];
  l    = new double [m * m];
  dlda = new double [m * n];

  // Read A from data file
  double   tmp;
  for (int i = 0; i < m; ++i) {
    for (int j = 0; j < n; ++j){
      cin >> tmp;
      a_in[i+j*m] = tmp;
    }
  }

  double d_zero = 0.0;
  for (int i = 0; i < m * n; i++) {
    // nagad_t1w_set_derivative(&a_in[i],d_zero);
    dco::derivative(a_in[i]) = d_zero;
    a[i] = a_in[i];
  }

  double d_one = 1.0;
  for (int j  = 0;  j < n; j++) {
    // nagad_t1w_set_derivative(&a[j*m],d_one);
    dco::derivative(a[j*m]) = d_one;
    f08ah_t1w_f_(ad_handle, m, n, a, pda, tau, work, lwork, ifail);
    if (ifail != 0) {
      printf("Error from F08AH_T1W_F .\n%" NAG_IFMT " ", ifail);
      exit_status = 1;
      goto END;
    }
    if (j==0) {
      for (int i = 0; i < m*m; ++i) {
        // l[i] = a[i].value
        l[i] = dco::value(a[i]);
      }
    }
   
    for (int i = 0; i < m; i++) {
      int ld = i*(m+1);
      int k = j*m + i;
      // drda[k] = a[l].tangent
      dlda[k] = dco::derivative(a[ld]);
    }

    for (int i = 0; i < m * n; i++)
      a[i] = a_in[i];
  }

  NagError  fail;
  INIT_FAIL(fail);
  x04cac(Nag_ColMajor,Nag_LowerMatrix,Nag_NonUnitDiag,m,m,l,m,
         "L from Q factorization of A",0,&fail);
  printf("\nDerivatives of diagonal of L w.r.t. first row of A\n");
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,m,n,dlda,m,
         "dL_ii/dA_j1",0,&fail);

 END:
  // Remove computational data object
  x10ab_t1w_f_(ad_handle,ifail);
  delete [] a;
  delete [] a_in;
  delete [] tau;
  delete [] l;
  delete [] dlda;
  delete [] work;

  return exit_status;
}