SPLINE Cubic spline data interpolation.
Given data vectors X and Y, and a new abscissa vector XI, the
function YI = SPLINE(X,Y,XI) uses cubic spline interpolation
to find a vector YI corresponding to XI.
Here's an example that generates a coarse sine curve, then
interpolates over a finer abscissa:
x = 0:10; y = sin(x);
xi = 0:.25:10;
yi = spline(x,y,xi);
plot(x,y,'o',xi,yi)
PP = spline(x,y) returns the pp-form of the cubic spline interpolant
instead, for later use with ppval, etc.
See also INTERP1, INTERP2, PPVAL, MKPP, UNMKPP, the Spline Toolbox.
PPVAL Evaluate piecewise polynomial.
v = ppval(pp,xx)
returns the value of the pp function pp at xx.
See also MKPP, UNMKPP, SPLINE.
MKPP Make piece-wise polynomial.
pp = mkpp(breaks,coefs)
puts together a pp function from the breaks and coefficients input or
requested. The number l of polynomial pieces is determined as
l := length(breaks)-1 .
The order k of the pp is obtained as
k := length(coefs)/l ,
and this ratio had better be an integer.
See also UNMKPP, PPVAL, SPLINE.
UNMKPP Supply details about piecewise polynomial.
[breaks,coefs,l,k] = unmkpp(pp)
takes apart the pp function into its pieces.
See also MKPP, SPLINE, PPVAL.