% Octave/Matlab example to plot a cubic spline through specified
%  points
%
% modified from
%  https://octave.sourceforge.io/octave/function/spline.html
%
% M.V.Wickerhauser
% 2019-10-11
% 
%

 x = 0:3; y = [1 1 5 6];       % knots
 xp = 0:0.1:3;                 % interpolated points
 yns = spline (x,y,xp);        % natural spline
 ycs = spline (x,[0,y,0],xp);  % clamped spline

% plot the knots, the natural spline, and the clamped spline
plot ( x,y,"r*", xp, yns,"g-", xp, ycs, "b-");
title ("Cubic spline fits to specified points", "fontsize",16);
legend ("knots","natural spline","clamped spline", "location","southeast" );