/* F06PA_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 <math.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 << "F06PA_A1W_F C++ Header Example Program Results\n\n";
  // Skip heading in data file
  string mystr;
  getline (cin, mystr);

  // Read problem size and parameters
  Integer m, n;
  cin >> m >> n;
  double alphar, betar;
  cin >> alphar >> betar;
  nagad_a1w_w_rtype alpha, beta;
  alpha = alphar;
  beta  = betar;
  
  // Allocate arrays containing A and its factorized form, B
  // and the solution X.
  nagad_a1w_w_rtype *a=0, *b=0, *y=0;
  double            *ar=0, *br=0, *yr=0, *da=0, *db=0;
  a    =  new nagad_a1w_w_rtype [m*n];
  b    =  new nagad_a1w_w_rtype [m];
  y    =  new nagad_a1w_w_rtype [n];
  ar   =  new double [m*n];
  br   =  new double [m];
  yr   =  new double [n];
  da   =  new double [n];
  db   =  new double [n];
  
  // Read the matrix A
  double dd;
  for (int i = 0; i<m; ++i) {
    for (int j = 0; j<n; ++j) {
      cin >> dd;
      Integer k = i + j*m;
      ar[k] = dd;
      a[k] = dd;
    }
  }
  for (int i = 0; i<m; ++i) {
    cin >> dd;
    br[i] = dd;
    b[i] = dd;
  }
  for (int i = 0; i<n; ++i) {
    yr[i] = 1.0;
    y[i] = 1.0;
  }

  // Create AD tape
  nagad_a1w_ir_create();

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

  nagad_a1w_ir_register_variable(&alpha);
  nagad_a1w_ir_register_variable(&beta);
  
  for (int i = 0; i<n; ++i) {
    yr[i] = nagad_a1w_get_value(y[i]);
  }

  //  y = beta*y + alpha*A^T*b
  ifail = 0;
  f06pa_a1w_f_(ad_handle,"T",m,n,alpha,a,m,b,1,beta,y,1,ifail,1);

  for (int i = 0; i<n; ++i) {
    yr[i] = nagad_a1w_get_value(y[i]);
  }

  cout << endl;
  NagError  fail;
  INIT_FAIL(fail);
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,n,1,yr,n,
         "  Array y after update",0,&fail);

  cout << "\n\n Derivatives calculated: First order adjoints\n";
  cout << " Computational mode    : algorithmic\n";
  cout << "\n Derivatives of y w.r.t alpha and beta:\n";

  for (int i = 0; i < n; ++i) {
    nagad_a1w_ir_zero_adjoints();
    double inc = 1.0;
    nagad_a1w_inc_derivative(&y[i],inc);
    ifail = 0;
    nagad_a1w_ir_interpret_adjoint(ifail);
    da[i] = nagad_a1w_get_derivative(alpha);
    db[i] = nagad_a1w_get_derivative(beta);
  }

  // Print derivatives
  cout << endl;
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,1,n,da,1,
         "           dy/dalpha",0,&fail);
  cout << endl;
  x04cac(Nag_ColMajor,Nag_GeneralMatrix,Nag_NonUnitDiag,1,n,db,1,
         "           dy/dbeta",0,&fail);

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

  return exit_status;
}