/* nag_nag_2d_shep_interp (e01sgc) Example Program.
 *
 * Copyright 2005 Numerical Algorithms Group.
 *
 * Mark 8, 2005.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nage01.h>

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;

  /* Scalars */
  Integer  exit_status, i, m, n, nq, nw;
  Integer  liq, lrq;

  /* Arrays */
  double   *f = 0, *q = 0, *qx = 0, *qy = 0, *rq = 0, *u = 0, *v = 0, *x = 0;
  double   *y = 0;
  Integer  *iq = 0;

  /* Nag Types */
  NagError fail;

  exit_status = 0;
  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  fprintf(fpout, "nag_2d_shep_interp (e01sgc) Example Program Results\n\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");

  /* Input the number of nodes. */
  fscanf(fpin, "%ld%*[^\n] ", &m);
  if (m > 6)
    {
      liq = 2*m+1;
      lrq = 6*m+5;
      /* Allocate memory */
      if (!(f = NAG_ALLOC(m, double)) ||
          !(rq = NAG_ALLOC(lrq, double)) ||
          !(x = NAG_ALLOC(m, double)) ||
          !(y = NAG_ALLOC(m, double)) ||
          !(iq = NAG_ALLOC(liq, Integer)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      fprintf(fpout, "Invalid m.\n");
      exit_status = 1;
      return exit_status;
    }

  /* Input the data points X,Y and F. */

  for (i = 1; i <= m; ++i)
    {
      fscanf(fpin, "%lf%lf%lf%*[^\n] ", &x[i - 1], &y[i - 1], &f[i - 1]);
    }

  /* Generate the interpolant. */
  nq = 0;
  nw = 0;
  /* nag_2d_shep_interp (e01sgc).
   * Interpolating functions, modified Shepard's method, two
   * variables
   */
  nag_2d_shep_interp(m, x, y, f, nw, nq, iq, rq, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_2d_shep_interp (e01sgc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Input the number of evaluation points. */
  fscanf(fpin, "%ld%*[^\n] ", &n);
  if (!(q = NAG_ALLOC(n, double)) ||
      !(qx = NAG_ALLOC(n, double)) ||
      !(qy = NAG_ALLOC(n, double)) ||
      !(u = NAG_ALLOC(n, double)) ||
      !(v = NAG_ALLOC(n, double)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = 1;
      goto END;
    }

  /* Input the evaluation points. */

  for (i = 1; i <= n; ++i)
    {
      fscanf(fpin, "%lf%lf%*[^\n] ", &u[i - 1], &v[i - 1]);
    }

  /* Evaluate the interpolant using nag_2d_shep_eval (e01shc). */

  /* nag_2d_shep_eval (e01shc).
   * Interpolated values, evaluate interpolant computed by
   * nag_2d_shep_interp (e01sgc), function and first
   * derivatives, two variables
   */
  nag_2d_shep_eval(m, x, y, f, iq, rq, n, u, v, q, qx, qy, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_2d_shep_interp (e01sgc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  fprintf(fpout, "%s", "     I      U(I)      V(I)      Q(I)");
  fprintf(fpout, "\n");
  for (i = 1; i <= n; ++i)
    {
      fprintf(fpout, "%6ld%10.2f%10.2f%10.2f\n", i, u[i - 1], v[i - 1],
              q[i - 1]);
    }

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (f) NAG_FREE(f);
  if (q) NAG_FREE(q);
  if (qx) NAG_FREE(qx);
  if (qy) NAG_FREE(qy);
  if (rq) NAG_FREE(rq);
  if (u) NAG_FREE(u);
  if (v) NAG_FREE(v);
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);
  if (iq) NAG_FREE(iq);

  return exit_status;
}