/* D01GA_A1W_F C++ Header Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
* Mark 30.1, 2024.
*/
#include <dco.hpp>
#include <iostream>
#include <math.h>
#include <nag.h>
#include <nagad.h>
#include <stdio.h>
using namespace std;
int main()
{
// Scalars
int exit_status = 0;
Integer n = 21;
double ar = 1.0;
cout << "D01GA_A1W_F C++ Header Example Program Results\n\n";
// Allocate memory
nagad_a1w_w_rtype *x = 0, *y = 0;
if (!(x = NAG_ALLOC(n, nagad_a1w_w_rtype)) ||
!(y = NAG_ALLOC(n, nagad_a1w_w_rtype)))
{
printf("Allocation failure\n");
exit_status = -2;
}
if (exit_status == 0)
{
// Create AD tape
dco::ga1s<double>::global_tape = dco::ga1s<double>::tape_t::create();
// Create AD configuration data object
Integer ifail = 0;
nag::ad::handle_t ad_handle;
/* Register variables to differentiate w.r.t. */
nagad_a1w_w_rtype a;
a = ar;
dco::ga1s<double>::global_tape->register_variable(a);
// Initialize variables
for (int i = 0; i < n; i++)
{
double xr = (1.0 * i) / (1.0 * (n - 1));
nagad_a1w_w_rtype tmp;
x[i] = xr;
tmp = a * x[i];
y[i] = 4.0 / (1.0 + tmp * tmp);
}
// Call the AD routine
ifail = 0;
nagad_a1w_w_rtype ans, er;
nag::ad::d01ga(ad_handle, x, y, n, ans, er, ifail);
double inc = 1.0;
dco::derivative(ans) += inc;
dco::ga1s<double>::global_tape->sparse_interpret() = true;
dco::ga1s<double>::global_tape->interpret_adjoint();
cout << "\n Derivatives calculated: First order adjoints\n";
cout << " Computational mode : algorithmic\n";
// Get derivative
double da;
da = dco::derivative(a);
cout.setf(ios::scientific, ios::floatfield);
cout.setf(ios::right);
cout.precision(4);
cout << "\n Solution, ans = ";
double ans_value = dco::value(ans);
cout.width(12);
cout << ans_value << endl;
cout << "\n Derivative:\n";
cout << " d(ans)/da = ";
cout.width(12);
cout << da << endl;
dco::ga1s<double>::tape_t::remove(dco::ga1s<double>::global_tape);
}
NAG_FREE(x);
NAG_FREE(y);
return exit_status;
}