/* F03BF_A1W_F C++ Header Example Program.
*
* Copyright 2023 Numerical Algorithms Group.
* Mark 29.2, 2023.
*/
#include <dco.hpp>
#include <iostream>
#include <nag.h>
#include <nagad.h>
#include <nagx04.h>
#include <stdio.h>
#include <string>
using namespace std;
int main()
{
int exit_status = 0;
nag::ad::handle_t ad_handle;
Integer ifail = 0;
cout << "F03BF_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_rtype *a = 0, *a_in = 0;
double * ar = 0;
a = new nagad_a1w_w_rtype[n * n];
a_in = new nagad_a1w_w_rtype[n * n];
ar = new double[n * n];
// Create AD tape
dco::ga1s<double>::global_tape = dco::ga1s<double>::tape_t::create();
// 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;
if (j <= i)
{
dco::ga1s<double>::global_tape->register_variable(a_in[k]);
}
a[k] = a_in[k];
ar[k] = dco::value(a[k]);
}
}
// Print matrix A
cout << endl;
NagError fail;
INIT_FAIL(fail);
x04cac(Nag_ColMajor, Nag_LowerMatrix, Nag_NonUnitDiag, n, n, ar, n, " A", 0,
&fail);
// Create AD configuration data object
ifail = 0;
// Factorize the matrix A
ifail = 0;
nag::ad::f07fd(ad_handle, "L", n, a, n, ifail);
// Print Factorization of A
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
int k = i + j * n;
ar[k] = dco::value(a[k]);
}
}
cout << endl;
// NagError fail;
INIT_FAIL(fail);
x04cac(Nag_ColMajor, Nag_LowerMatrix, Nag_NonUnitDiag, n, n, ar, n,
" Array A after factorization", 0, &fail);
nagad_a1w_w_rtype d;
Integer id;
ifail = 0;
nag::ad::f03bf(ad_handle, n, a, n, d, id, ifail);
cout << "\n d = " << dco::value(d) << " id = " << id << endl;
cout << "\n value of determinant = " << dco::value(d) * pow(2.0, id);
cout << endl;
// Obtain derivatives
cout << "\n\n Derivatives calculated: First order adjoints\n";
cout << " Computational mode : algorithmic\n";
cout << "\n Derivatives of d w.r.t to A:\n";
double inc = 1.0;
dco::derivative(d) += inc;
ifail = 0;
dco::ga1s<double>::global_tape->sparse_interpret() = true;
dco::ga1s<double>::global_tape->interpret_adjoint();
for (int i = 0; i < n; i++)
{
for (int j = 0; j <= i; j++)
{
Integer k = i + j * n;
double dd = dco::derivative(a_in[k]);
ar[k] = dd;
}
}
// Print derivatives
cout << endl;
INIT_FAIL(fail);
x04cac(Nag_ColMajor, Nag_LowerMatrix, Nag_NonUnitDiag, n, n, ar, n,
" d(d)/da(i,j)", 0, &fail);
ifail = 0;
dco::ga1s<double>::tape_t::remove(dco::ga1s<double>::global_tape);
return exit_status;
}