cubic spline interpolation

carl982002

New member
hi all

ive been searching the net for some time on the above topic and cant seem to find a clear a to z guide and hoped for some help.
my basic mission is to be able to create a curve from a cubic spline function.
ive a thin idea of the subject.
its my understanding that a domain of integras are used.
vertices are used as points on what i vision as a x,y map
here's where im failing, if i have say 3 vertices and want to plot a curve how do i feed these points into a cubic spline function?
and how do i obtion say 255 output points from the 3 original vertices? for a 255x255 x,y graph?

any help here would be greatly apprechiated
thanx

tkhunny

Moderator
Staff member
"vertices"?

Why would graphing a curve from a cubic spline be any different from a cruve not from a cubic spline?

carl982002

New member
i will do more research. however i dont fully understand how to the points vertices into the function to obtain y

carl982002

New member
im not sure wether my last reply will be added but how do i get the individual new output x,y co ords from 3 inputs. without having 255 x's to obtain y again i will research more.

tkhunny

Moderator
Staff member
There are a couple of purposes to the spline.

1) We don't really know the underlying function, and
2) The function we have is really ugly,

So, let's create one we can deal with. Since we can't create anything particularly convenient over the entire Domain, let's do just a piece at a time.

There is an old graphical device known as a "spline". It had weights and connectors of different stiffness. Look it up. It's an interesting read.

When you say "values from the spline function" I become nervous. Generally, we would want good values to represent the underlying function.