/* D01FB_P0W_F C++ Header Example Program.
*
* Copyright 2023 Numerical Algorithms Group.
* Mark 29.1, 2023.
*/
#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 ndim = 4;
cout << "D01FB_P0W_F C++ Header Example Program Results\n\n";
// Allocate memory
Integer *nptvec = 0;
double * abscis = 0, *weight = 0;
Integer lwa = 0;
nptvec = new Integer[ndim];
for (int i = 0; i < ndim; i++)
{
nptvec[i] = 4;
lwa = lwa + nptvec[i];
}
abscis = new double[lwa];
weight = new double[lwa];
nag::ad::handle_t ad_handle;
// Evaluate primal weights and abscisae in each dimension
int j = 0;
for (int i = 0; i < ndim; i++)
{
Integer ifail = 0, quadtype = 0;
double a, b;
switch (i)
{
case 0:
a = 1.0;
b = 2.0;
quadtype = 0;
break;
case 1:
a = 0.0;
b = 2.0;
quadtype = -3;
break;
case 2:
a = 0.0;
b = 0.5;
quadtype = -4;
break;
case 3:
a = 1.0;
b = 2.0;
quadtype = -5;
break;
}
nag::ad::d01tb(ad_handle, quadtype, a, b, nptvec[i], &weight[j], &abscis[j],
ifail);
j = j + nptvec[i];
}
// Call the passive routine
Integer ifail = 0;
double ans;
auto fun = [&](nag::ad::handle_t & ad_handle,
const Integer & ndim,
const double *x,
double & ret)
{
// dco/c++ overloading used here to perform AD
double p1 = 6.0, p2 = 8.0;
double r1, r2;
// Split the following function into manageable chunks
// ret = (pow(x[0]*x[1]*x[2],p1)/pow(x[3]+2.0,p2))*
// exp(-2.0*x[1]-0.5*x[2]*x[2]);
r1 = x[2] * x[2];
r1 = 0.5 * r1;
r2 = -2.0 * x[1];
r1 = r2 - r1;
ret = exp(r1);
r1 = x[0] * x[1] * x[2];
r1 = pow(r1, p1);
r2 = x[3] + 2.0;
r2 = pow(r2, p2);
r2 = r1 / r2;
ret = ret * r2;
};
nag::ad::d01fb(ad_handle, ndim, nptvec, lwa, weight, abscis, fun, ans, ifail);
cout.setf(ios::right);
cout.precision(4);
cout << "\n Solution, x = ";
cout.width(12);
cout << ans << endl;
delete[] nptvec;
delete[] abscis;
delete[] weight;
return exit_status;
}