Talk:De Boor's algorithm

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Untitled

In the definition of the 0-th degree B-spline basis functions, the closed interval between u[i] and u[i+1] should be replaced by the half-open interval between u[i] and u[i+1].

Expressed otherwise, the article presently gives the requirement that we should have u[i] <= x <= u[i+1] but this requirement should really be u[i] <= x < u[i+1].

I would make this change myself, but I do not know how to do this in MathML.

Rdfuhr (talk) 06:15, 14 June 2010 (UTC)[reply]

Done. --TN (talk) 08:53, 4 August 2017 (UTC)[reply]

Why are n and p reversed?

I believe it is a fairly standard convention to have p be the degree of the curve and n either be the highest index (modus Peigl and Tiller), or the number of control points (highest index + 1).

Why is this convention reversed so that p is the number of control points and n is the degree?

CodieCodemonkey (talk) 08:52, 22 May 2012 (UTC)[reply]

Misleading terminology in introduction

In the introduction, there is some unclarity whether the autor is talking about 'control points' or 'internal knots'. Control points do not (neccessarily) lie on the b-spline curve. The introduction states that the curve should try to satisfy $\mathbf {s} (u_{0})=\mathbf {d} _{0},\dots ,\mathbf {s} (u_{p-1})=\mathbf {d} _{p-1}$ , which would be valid if $\mathbf {d} _{i}$ were the knot points / internal knots, but not for the control points! Might be that I misunderstood the meaning, but it's not written very clearly. Timitry (talk) 13:20, 11 July 2016 (UTC)[reply]