[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: fulfill the (cubic) basis splines the partition of unity at all poin

From: Patrick Alken
Subject: Re: fulfill the (cubic) basis splines the partition of unity at all points in [a,b]?
Date: Wed, 8 Mar 2023 00:11:24 -0500
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1

Its also worth mentioning that there has been a substantial overhaul to the B-splines routines since v2.7. The new routines are on the git repository, along with documentation. If you have the ability to clone the git and build the documentation from there I highly encourage it. There are many example programs in the git documentation which are not in the 2.7 docs which may help you.

On 3/7/23 22:07, Rhys Ulerich wrote:
This time remembering to CC the mailing list...

On Tue, Mar 7, 2023, 9:57 PM Rhys Ulerich <> wrote:

On Tue, Mar 7, 2023, 5:11 PM Simon Wiesheier <>

After reading the manual, it is not clear to me how GNU internally
constructs the knot vector.
There are the functions,
that create the knot vector based on given breakpoints.

I encourage you to initialize a cubic workspace (k=4, pick nbreak) then to
use gsl_bspline_knots_uniform to have the GSL construct the knot vector for
you given some [a, b]. You will be able to observe the multiplicity of the
various knots in the resulting w->knots. The multiplicity is a consequence
of the chosen k meaning that if you opted for quadratic or quintic k you
will see a different knot multiplicity. Play around a bit.

You may (or may not) find the routines at to be
useful worked examples. Those include forming linear combinations of the

- Rhys

reply via email to

[Prev in Thread] Current Thread [Next in Thread]