NAG Library Manual, Mark 27.2
Interfaces:  FL   CL   CPP   AD 

NAG AD Library Introduction
Example description
/* E04WB_A1W_F C++ Header Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 * Mark 27.2, 2021.
 */

#include <dco.hpp>
#include <iostream>
#include <math.h>
#include <nag.h>
#include <nagad.h>
#include <stdio.h>
#include <string>
using namespace std;

extern "C"
{
  static void NAG_CALL objfun(void *&                 ad_handle,
                              Integer &               mode,
                              const Integer &         m,
                              const Integer &         n,
                              const Integer &         ldfj,
                              const Integer &         needfi,
                              const nagad_a1w_w_rtype x[],
                              nagad_a1w_w_rtype       f[],
                              nagad_a1w_w_rtype       fjac[],
                              const Integer &         nstate,
                              Integer                 iuser[],
                              nagad_a1w_w_rtype       ruser[]);
  static void NAG_CALL confun(void *&                 ad_handle,
                              Integer &               mode,
                              const Integer &         ncnln,
                              const Integer &         n,
                              const Integer &         ldcj,
                              const Integer           needc[],
                              const nagad_a1w_w_rtype x[],
                              nagad_a1w_w_rtype       c[],
                              nagad_a1w_w_rtype       cjac[],
                              const Integer &         nstate,
                              Integer                 iuser[],
                              nagad_a1w_w_rtype       ruser[]);
}

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

  cout << "E04WB_A1W_F C++ Header Example Program Results\n\n";

  // Create AD tape
  dco::ga1s<double>::global_tape = dco::ga1s<double>::tape_t::create();

  // Create AD configuration data object
  Integer ifail     = 0;
  void *  ad_handle = 0;
  nag::ad::x10aa(ad_handle, ifail);

  // Skip first line of data file
  string mystr;
  getline(cin, mystr);

  // Read problem sizes
  Integer m, n, nclin, ncnln;
  cin >> m;
  cin >> n;
  cin >> nclin;
  cin >> ncnln;

  Integer liwork = 3 * n + nclin + 2 * ncnln;
  Integer lda = nclin, sda = n, ldcj = ncnln, ldfj = m, ldr = n;
  Integer lwork;

  lwork = 20 * n + m * (n + 3);
  if (nclin > 0)
    {
      lwork = lwork + 2 * n * n + 11 * nclin;
    }
  if (ncnln > 0)
    {
      lwork = lwork + n * nclin + (2 * n + 21) * ncnln;
    }
  Integer            lb = n + nclin + ncnln;
  nagad_a1w_w_rtype *a = 0, *bl = 0, *bu = 0, *y = 0, *c = 0, *cjac = 0, *f = 0;
  nagad_a1w_w_rtype *fjac = 0, *clamda = 0, *r = 0, *x = 0, *work = 0,
                    *rwsav = 0;
  Integer *istate = 0, *iwork = 0, *iwsav = 0;
  logical *lwsav = 0;
  double * dr = 0, *rwsav_r = 0;
  if (!(a = NAG_ALLOC(lda * sda, nagad_a1w_w_rtype)) ||
      !(bl = NAG_ALLOC(lb, nagad_a1w_w_rtype)) ||
      !(bu = NAG_ALLOC(lb, nagad_a1w_w_rtype)) ||
      !(y = NAG_ALLOC(m, nagad_a1w_w_rtype)) ||
      !(c = NAG_ALLOC(ncnln, nagad_a1w_w_rtype)) ||
      !(cjac = NAG_ALLOC(ncnln * n, nagad_a1w_w_rtype)) ||
      !(f = NAG_ALLOC(m, nagad_a1w_w_rtype)) ||
      !(fjac = NAG_ALLOC(m * n, nagad_a1w_w_rtype)) ||
      !(clamda = NAG_ALLOC(lb, nagad_a1w_w_rtype)) ||
      !(r = NAG_ALLOC(ldr * n, nagad_a1w_w_rtype)) ||
      !(x = NAG_ALLOC(n, nagad_a1w_w_rtype)) ||
      !(work = NAG_ALLOC(lwork, nagad_a1w_w_rtype)) ||
      !(rwsav = NAG_ALLOC(475, nagad_a1w_w_rtype)) ||
      !(lwsav = NAG_ALLOC(120, logical)) ||
      !(rwsav_r = NAG_ALLOC(475, double)) || !(dr = NAG_ALLOC(n * n, double)) ||
      !(istate = NAG_ALLOC(lb, Integer)) ||
      !(iwork = NAG_ALLOC(liwork, Integer)) ||
      !(iwsav = NAG_ALLOC(610, Integer)))
    {
      cout << "Allocation failure\n";
      exit_status = -1;
    }
  else
    {

      // Read problem parameters and register for differentiation
      double yr;
      for (int i = 0; i < nclin; i++)
        {
          for (int j = 0; j < sda; j++)
            {
              Integer k = i + j * nclin;
              cin >> yr;
              a[k] = yr;
            }
        }
      for (int i = 0; i < m; i++)
        {
          cin >> yr;
          y[i] = yr;
        }
      for (int i = 0; i < lb; i++)
        {
          cin >> yr;
          bl[i] = yr;
        }
      for (int i = 0; i < lb; i++)
        {
          cin >> yr;
          bu[i] = yr;
        }
      for (int i = 0; i < n; i++)
        {
          cin >> yr;
          x[i] = yr;
        }

      double rr[44] = {8.0,  8.0,  10.0, 10.0, 10.0, 10.0, 12.0, 12.0, 12.0,
                       12.0, 14.0, 14.0, 14.0, 16.0, 16.0, 16.0, 18.0, 18.0,
                       20.0, 20.0, 20.0, 22.0, 22.0, 22.0, 24.0, 24.0, 24.0,
                       26.0, 26.0, 26.0, 28.0, 28.0, 30.0, 30.0, 30.0, 32.0,
                       32.0, 34.0, 36.0, 36.0, 38.0, 38.0, 40.0, 42.0};
      nagad_a1w_w_rtype ruser[44];
      for (int i = 0; i < 44; i++)
        {
          ruser[i] = rr[i];
          dco::ga1s<double>::global_tape->register_variable(ruser[i]);
        }

      // Initialize sav arrays
      ifail = 0;
      char cwsav[1];
      nag::ad::e04wb("E04USA", cwsav, 1, lwsav, 120, iwsav, 610, rwsav, 475,
                     ifail);

      // Solve the problem
      Integer           iter, iuser[1];
      nagad_a1w_w_rtype objf;
      ifail = -1;
      nag::ad::e04us(ad_handle, m, n, nclin, ncnln, lda, ldcj, ldfj, ldr, a, bl,
                     bu, y, confun, objfun, iter, istate, c, cjac, f, fjac,
                     clamda, objf, r, x, iwork, liwork, work, lwork, -1, iuser,
                     -1, ruser, lwsav, iwsav, rwsav, ifail);

      // Primal results
      cout.setf(ios::scientific, ios::floatfield);
      if (ifail == 0 || ifail > 1)
        {
          cout.precision(4);
          cout << "\n Optimal objective function value = ";
          cout.width(12);
          cout << dco::value(objf);
          cout << "\n Solution point = ";
          for (int i = 0; i < n; i++)
            {
              cout.width(12);
              cout << dco::value(x[i]);
            }
          cout << endl;
        }
      else
        {
          cout << "nag::ad::e04us failed with ifail = " << ifail << endl;
          goto END;
        }

      cout << "\n Derivatives calculated: First order adjoints\n";
      cout << " Computational mode    : algorithmic\n\n";
      cout << " Derivatives:\n\n";

      // Setup evaluation of derivatives of fsumsq via adjoints.
      double inc = 1.0;
      dco::derivative(x[0]) += inc;
      ifail                                              = 0;
      dco::ga1s<double>::global_tape->sparse_interpret() = true;
      dco::ga1s<double>::global_tape->interpret_adjoint();

      // Get derivatives of x[0] w.r.t. ruser
      cout << "  derivatives of x[0] w.r.t ruser[0:43]:\n";
      for (int i = 0; i < 44; i++)
        {
          double d = dco::derivative(ruser[i]);
          cout.width(12);
          cout << d;
          if (i % 4 == 3)
            {
              cout << endl;
            }
        }
    }
END:
  // Remove computational data object and tape
  nag::ad::x10ab(ad_handle, ifail);
  dco::ga1s<double>::tape_t::remove(dco::ga1s<double>::global_tape);

  return exit_status;
}

static void NAG_CALL objfun(void *&                 ad_handle,
                            Integer &               mode,
                            const Integer &         m,
                            const Integer &         n,
                            const Integer &         ldfj,
                            const Integer &         needfi,
                            const nagad_a1w_w_rtype x[],
                            nagad_a1w_w_rtype       f[],
                            nagad_a1w_w_rtype       fjac[],
                            const Integer &         nstate,
                            Integer                 iuser[],
                            nagad_a1w_w_rtype       ruser[])
{
  nagad_a1w_w_rtype x1, x2;
  x1 = x[0];
  x2 = x[1];

  if (mode == 0 && needfi > 0)
    {
      f[needfi - 1] = x1 + (0.49 - x1) * exp(-x2 * (ruser[needfi - 1] - 8.0));
    }
  else
    {
      for (int i = 0; i < m; ++i)
        {
          nagad_a1w_w_rtype ai   = ruser[i] - 8.0;
          nagad_a1w_w_rtype temp = exp(-x2 * ai);

          if (mode == 0 || mode == 2)
            {
              f[i] = x1 + (0.49 - x1) * temp;
            }
          if (mode == 1 || mode == 2)
            {
              fjac[i]     = 1.0 - temp;
              fjac[i + m] = -(0.49 - x1) * ai * temp;
            }
        }
    }
  return;
}
static void NAG_CALL confun(void *&                 ad_handle,
                            Integer &               mode,
                            const Integer &         ncnln,
                            const Integer &         n,
                            const Integer &         ldcj,
                            const Integer           needc[],
                            const nagad_a1w_w_rtype x[],
                            nagad_a1w_w_rtype       c[],
                            nagad_a1w_w_rtype       cjac[],
                            const Integer &         nstate,
                            Integer                 iuser[],
                            nagad_a1w_w_rtype       ruser[])
{
  if (nstate == 1)
    {
      for (int i = 0; i < ncnln * n; ++i)
        {
          cjac[i] = 0.0;
        }
    }
  if (needc[0] > 0)
    {
      if (mode == 0 || mode == 2)
        {
          c[0] = -0.09 - x[0] * x[1] + 0.49 * x[1];
        }
      if (mode == 1 || mode == 2)
        {
          cjac[0]     = -x[1];
          cjac[ncnln] = -x[0] + 0.49;
        }
    }
  return;
}