/* nag_1d_spline_fit_knots(e02bac) Example Program
 *
 * Copyright 1996 Numerical Algorithms Group.
 *
 * Mark 4, 1996.
 *
 * Mark 6 revised, 2000.
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nage02.h>

#define MMAX 200

int main(void)
{
  Integer ncap, ncap7, j, m, r, wght;
  double weights[MMAX], x[MMAX], y[MMAX], xarg, ss, fit;
  Nag_Spline spline;

  Vprintf("e02bac Example Program Results\n");
  Vscanf("%*[^\n]");  /* Skip heading in data file */
  while(scanf("%ld",&m) != EOF)
    {
      if (m>0 && m<=MMAX)
        {
          Vscanf("%ld%ld",&ncap,&wght);
          if (ncap>0)
            {
              ncap7 = ncap+7;
              spline.n = ncap7;
              spline.lamda = NAG_ALLOC(ncap7, double);
              if (spline.lamda != (double *)0)
                {
                  for (j=4; j<ncap+3; ++j)
                    Vscanf("%lf",&(spline.lamda[j]));
                  for (r=0; r<m; ++r)
                    {
                      if (wght==1)
                        {
                          Vscanf("%lf%lf",&x[r],&y[r]);
                          weights[r] = 1.0;
                        }
                      else
                        Vscanf("%lf%lf%lf",&x[r],&y[r],&weights[r]);
                    }
                  e02bac(m, x, y, weights, &ss, &spline, NAGERR_DEFAULT);
                  Vprintf("\nNumber of distinct knots = %ld\n\n", ncap+1);
                  Vprintf("Distinct knots located at \n\n");
                  for (j=3; j<ncap+4; j++)
                    Vprintf("%8.4f%s",spline.lamda[j],
                            (j-3)%6==5 || j==ncap+3 ? "\n" : " ");
                  Vprintf("\n\n    J    B-spline coeff c\n\n");
                  for (j=0;  j<ncap+3; ++j)
                    Vprintf("    %ld  %13.4f\n",j+1,spline.c[j]);
                  Vprintf("\nResidual sum of squares = ");
                  Vprintf("%9.2e\n\n",ss);
                  Vprintf("Cubic spline approximation and residuals\n");
                  Vprintf("  r        Abscissa        Weight       Ordinate"
                          "          Spline      Residual\n\n");
                  for (r=0; r<m; ++r)
                    {
                      e02bbc(x[r], &fit, &spline, NAGERR_DEFAULT);
                      Vprintf("%3ld    %11.4f    %11.4f    %11.4f     %11.4f"
                              "    %10.1e\n",r+1,x[r],weights[r],y[r],fit,fit-y[r]);
                      if (r<m-1)
                        {
                          xarg = (x[r] + x[r+1]) * 0.5;
                          e02bbc(xarg, &fit, &spline, NAGERR_DEFAULT);
                          Vprintf("    %14.4f             %33.4f\n",xarg,fit);
                        }
                    }
                  /* Free memory used by spline */
                  NAG_FREE(spline.lamda);
                  NAG_FREE(spline.c);
                }
              else
                {
                  Vfprintf(stderr,"Sufficient space is not available, "
                           "reduce the value of ncap");
                  return EXIT_FAILURE;
                }
            }
          else
            {
              Vfprintf(stderr,"ncap is negative or zero: ncap = %ld\n",ncap);
              return EXIT_FAILURE;
            }
        }
      else
        {
          Vfprintf(stderr,"m is out of range : m = %ld\n",m);
          return EXIT_FAILURE;
        }
    }
  return EXIT_SUCCESS;
}