Thread Subject: B-Spline basis function extraction

Hi,

Given a knot sequence, I want to obtain the collection basis funtions
for the B-Spline that will stand on the knots. I thought the command
'bspline' would do it, but not.

Anyone?


Fajar

fajar <fajar96te@yahoo.com> wrote in message
> I thought the command
> 'bspline' would do it, but not.
>

help spline

Bruno

fajar <fajar96te@yahoo.com> wrote in message
<a5a66d2a-b0a5-4d47-8642-a5608bf0e734@b5g2000pri.googlegroups.com>...
>
> Hi,
>
> Given a knot sequence, I want to obtain the collection
basis funtions
> for the B-Spline that will stand on the knots. I thought
the command
> 'bspline' would do it, but not.
>
> Anyone?
>
>
> Fajar

Hello,

I'm also working on B-Splines now. You have to apply the
command 'spmak' to your knot sequence like

fnplt(spmak(0:10,1));

The command 'fnplt' plot it then.

I have one different problem which 3 dimensional Basis
Splines. If you have the solution for my question 'Picture
of Basis Splines.

Good luck!

Say I want to have 10 knots and splines of order 3, with the support
of each of the splines being [-1 2],[0 3],...,[8 11]
You can use the function spmak to generate a B-spline function of
dimension 10 that has a coefficient of 1 on each of the knots like
this

>> myspline=spmak(-1:11,eye(10))

myspline =

      form: 'B-'
     knots: [-1 0 1 2 3 4 5 6 7 8 9 10 11]
     coefs: [10x10 double]
    number: 10
     order: 3
       dim: 10

Each of the dimensions corresponds to an element of the basis

To visualize, then do for example
>> x=-1:0.1:11;
>> y=spval(myspline,x);
>> plot(x,y);