/* S01BA_A1W_F C Header Example Program.
 *
 * Copyright 2017 Numerical Algorithms Group.
 * Mark 26.2, 2017.
 */

#include <nag.h>
#include <nagad.h>
#include <stdio.h>
#include <nag_stdlib.h>

int main(void)
{
  /* Scalars */
  int               exit_status = 0;
  nagad_a1w_w_rtype x, y;
  Integer           i, ifail, n;
  double            dydx, inc, xr;

  /* Arrays */
  nagad_a1w_w_rtype *xv = 0;
  void              *ad_handle = 0;

  printf("S01BA_A1W_F C Header Example Program Results\n\n");
  /* Skip heading in data file */
#ifdef _WIN32
  scanf_s("%*[^\n]");
#else
  scanf("%*[^\n]");
#endif
#ifdef _WIN32
  scanf_s("%" NAG_IFMT "%*[^\n] ", &n);
#else
  scanf("%" NAG_IFMT "%*[^\n] ", &n);
#endif

  /* Allocate memory */
  if (!(xv = NAG_ALLOC(n, nagad_a1w_w_rtype)))
  {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Read x values from data file */
  for (i = 0; i < n; ++i) {
#ifdef _WIN32
    scanf_s("%lf", &xr);
#else
    scanf("%lf", &xr);
#endif
    xv[i].value = xr;
    xv[i].id = 0;
  }
#ifdef _WIN32
  scanf_s("%*[^\n] ");
#else
  scanf("%*[^\n] ");
#endif

  printf("\n       x       y=ln(1+x)     dy/dx\n");

  /*     Create AD tape */
  nagad_a1w_ir_create();

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

  for (i = 0; i < n; ++i) {
    x = xv[i];
    /*   Register variables to differentiate w.r.t. */
    nagad_a1w_ir_register_variable(&x);

    ifail = -1;
    s01ba_a1w_f_(&ad_handle,&x,&y,&ifail);
    
    nagad_a1w_ir_zero_adjoints();
    inc = 1.0;
    nagad_a1w_inc_derivative(&y,inc);
    ifail = 0;
    nagad_a1w_ir_interpret_adjoint(&ifail);

    /*       Get derivatives */
    dydx = nagad_a1w_get_derivative(x);

    if (ifail<0) {
      printf(" %12.4e %12s%" NAG_IFMT "\n", x.value, "fail = ", ifail);
    } else {
      printf(" %12.4e %12.4e %12.4e\n", x.value, y.value, dydx);
    }
  }

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

 END:
  NAG_FREE(xv);
  return exit_status;
}