readlib(bspline):
with(plots):

#
#	Construct basis functions of degree n in variable u for knot vector k.
#
Bfunction := proc(n, k, u)
	local i,j;

	seq( convert(bspline(n,u,[k[i]$i=j..j+n+1]), procedure),
		j=1..nops(k)-n-1);
end:


pairs := proc(x,y)
	local i;
	[x[i], y[i]] $ i=1..nops(x);
end:

#
#	Construct degree-n B-spline approximation to points x on knot vector k
#	over indeterminate t.
#

BsplineApprox := proc(n,x,k,u)
	local i,BS;

	BS := Bfunction(n,k,u); 
	sum(x[i+n-1]*BS[i],i=1..nops(k)-n-1);
end: