#
# Numerical Mathematics and Computing, Fifth Edition
# Ward Cheney & David Kincaid
# Brooks/Cole Publ. Co.
# (c) 2003
#
# file:  cubic_spline1
#
# Generate and plot the natural cubic spline function
# for the data (x,y) = {(-1,1), (0,2), (1,-1)}

 readlib(spline):
 S := spline([-1, 0, 1], [1, 2, -1], x, cubic);
 plot(S(x),x= -1..1);