Re: Spline

[Carlo de Falco]

On 15/gen/09, at 11:15, dmelliott wrote:

> Dear Help,
>
>     It is not clear to me whether the derivatives to be used in the  
> spline function are those at the ends of the old range or those to  
> be applied at the ends of the new range.  Since the new domain and  
> the old can be quite different, this could cause problems.
>                                                                                                                  Thanks 
>   
> again 
> ,                                                                                                                       dmelliott

I am not sure what you mean by "new range" and "old range" the help  
text says:

If the length of Y is `N + 2',
then the first and last values of the vector Y are the values of
the first derivative of the cubic spline at the end-points.

which means that the piece-wise polynomial S(x) produced by 'spline'  
is such that

S'(x(1)) = y(1)
S'(x(end)) = y(end)

c.