e02bfce.c

/* nag_fit_dim1_spline_deriv_vector (e02bfc) Example Program.
 *
 * Copyright 2025 Numerical Algorithms Group.
 *
 * Mark 31.1, 2025.
 */
#include<nag.h>
#include<stdio.h>
intmain(void){
#define S(I, J) s[(J - 1) * pds + I - 1]
Integerexit_status=0;
doublefp,sfac;
Integerpds,liwrk,m,nest,nx,d,j;
double*s=0,*wdata=0,*x=0,*xdata=0,*ydata=0;
Integer*iwrk=0,*ixloc=0;
Nag_Commwarmstartinf;
Nag_Splinespline;
Nag_Startstart_e02bec;
Nag_SplineVectorSortstart;
Nag_Booleanxord;
Nag_DerivTypederiv;
NagErrorfail;
printf("nag_fit_dim1_spline_deriv_vector (e02bfc) Example Program Results\n");
INIT_FAIL(fail);
/* Initialize spline */
spline.lamda=0;
spline.c=0;
warmstartinf.nag_w=0;
warmstartinf.nag_iw=0;
/* Skip heading in data file */
scanf("%*[^\n] ");
/* Input the number of data points for the spline, */
/* followed by the data points (xdata), the function values (ydata) */
/* and the weights (wdata). */
scanf("%"NAG_IFMT"",&m);
scanf("%*[^\n] ");
nest=m+4;
if(m>=4){
if(!(wdata=NAG_ALLOC(m,double))||!(xdata=NAG_ALLOC(m,double))||
!(ydata=NAG_ALLOC(m,double))){
printf("Allocation failure\n");
exit_status=-1;
gotoEND;
}
}else{
printf("Invalid m.\n");
exit_status=1;
returnexit_status;
}
start_e02bec=Nag_Cold;
for(j=0;j<m;j++){
scanf("%lf",&xdata[j]);
scanf("%lf",&ydata[j]);
scanf("%lf",&wdata[j]);
}
scanf("%*[^\n] ");
/* Read in the requested smoothing factor. */
scanf("%lf",&sfac);
scanf("%*[^\n] ");
/* Determine the spline approximation.
 * nag_fit_dim1_spline_auto (e02bec).
 * Least squares cubic spline curve fit, automatic knot placement,
 * one variable.
 */
nag_fit_dim1_spline_auto(start_e02bec,m,xdata,ydata,wdata,sfac,nest,
&fp,&warmstartinf,&spline,&fail);
if(fail.code!=NE_NOERROR){
printf("Error from nag_fit_dim1_spline_auto (e02bec).\n%s\n",fail.message);
exit_status=2;
gotoEND;
}
/* Read in the number of sample points requested. */
scanf("%"NAG_IFMT"",&nx);
scanf("%*[^\n] ");
/* Allocate memory for sample point locations and */
/* function and derivative approximations. */
pds=nx;
liwrk=3+3*nx;
if(!(x=NAG_ALLOC(nx,double))||!(s=NAG_ALLOC(pds*4,double))||
!(ixloc=NAG_ALLOC(nx,Integer))||
!(iwrk=NAG_ALLOC(liwrk,Integer))){
printf("Allocation failure\n");
exit_status=-1;
gotoEND;
}
/* Read in sample points. */
for(j=0;j<nx;j++)
scanf("%lf",&x[j]);
scanf("%*[^\n] ");
xord=Nag_FALSE;
start=Nag_SplineVectorSort_Sorted;
deriv=Nag_RightDerivs_3;
/*
 * nag_fit_dim1_spline_deriv_vector (e02bfc).
 * Evaluation of fitted cubic spline, function and optionally derivatives
 * at a vector of points.
 */
nag_fit_dim1_spline_deriv_vector(start,&spline,deriv,xord,x,ixloc,nx,s,
pds,iwrk,liwrk,&fail);
switch(fail.code){
caseNE_NOERROR:
caseNW_SOME_SOLUTIONS:{
/* Output the results. */
printf("\n");
printf(" x ixloc s(x) ");
printf(" ds/dx d2s/dx2 d3s/dx3\n");
for(j=0;j<nx;j++){
if(ixloc[j]>=4&&ixloc[j]<=spline.n-3){
printf("%8.4f %7"NAG_IFMT" ",x[j],ixloc[j]);
for(d=0;d<4;d++)
printf("%12.4e ",S(j+1,d+1));
printf("\n");
}else
printf("%f %"NAG_IFMT"\n",x[j],ixloc[j]);
}
break;
}
default:{
printf("Error from nag_fit_dim1_spline_deriv_vector (e02bfc).\n%s\n",
fail.message);
exit_status=3;
gotoEND;
}
}
END:
NAG_FREE(xdata);
NAG_FREE(ydata);
NAG_FREE(wdata);
NAG_FREE(warmstartinf.nag_w);
NAG_FREE(warmstartinf.nag_iw);
NAG_FREE(spline.lamda);
NAG_FREE(spline.c);
NAG_FREE(x);
NAG_FREE(ixloc);
NAG_FREE(s);
NAG_FREE(iwrk);
returnexit_status;
}