double dpoly (int_t n, double x, const double* xp, const double* yp)
{
double value, err;
dpolint (xp - 1, yp - 1, n, x, &value, &err);
return value;
}
int dpolcof(double *xa, double *ya, int n, double *cof) {
double xmin=0.0,dy=0.0;
double *x=NULL,*y=NULL;
int i=0,j=0,k=0;
/* Allocate memory for temporary arrays and fill them */
if ((x=darray(n))==NULL) {
errormsg("dpolcof(): Cannot allocate memory to x array\n\to size %s",n);
return 0;
}
if ((y=darray(n))==NULL) {
errormsg("dpolcof(): Cannot allocate memory to y array\n\to size %s",n);
return 0;
}
for (i=0; i<n; i++) { x[i]=xa[i]; y[i]=ya[i]; }
for (j=0; j<n; j++) {
if (!dpolint(x,y,n-j,0.0,&cof[j],&dy)) {
nferrormsg("dpolcof(): Error returned from dpolint()"); return 0;
}
xmin=FIT_INFIN; k=-1;
for (i=0; i<n-j; i++) {
if (abs(x[i])<xmin) { xmin=fabs(x[i]); k=i; }
if (x[i]) y[i]=(y[i]-cof[j])/x[i];
}
for (i=k+1; i<n-j; i++) { y[i-1]=y[i]; x[i-1]=x[i]; }
}
/* Clean up */
free(x); free(y);
return 1;
}
