//---------------------------------------------------------------------------
void spline (double x[], double y[], int n, double y2[]);
int splint (double xa[], double ya[], double y2[], int na, double xs[], double ys[], int ns);
int spld1(double xa[], double ya[], double y2[], int na, double xs[], double ys[], int ns);
int spli1(double xa[], double ya[], double y2[], int na, double xs[], double ys[], int ns);