From 4027d3af0f1a3d447da4eb97f16908538420ffe4 Mon Sep 17 00:00:00 2001 From: Martin Thoma Date: Sun, 6 Mar 2016 15:10:39 +0100 Subject: [PATCH] Remove document as it is out of scope for this project --- documents/c2-bezier-spline/Makefile | 8 --- .../c2-bezier-spline/minimal-document.tex | 50 ------------------- 2 files changed, 58 deletions(-) delete mode 100644 documents/c2-bezier-spline/Makefile delete mode 100644 documents/c2-bezier-spline/minimal-document.tex diff --git a/documents/c2-bezier-spline/Makefile b/documents/c2-bezier-spline/Makefile deleted file mode 100644 index 4bc4573..0000000 --- a/documents/c2-bezier-spline/Makefile +++ /dev/null @@ -1,8 +0,0 @@ -SOURCE=minimal-document - -make: - pdflatex $(SOURCE).tex -output-format=pdf - make clean - -clean: - rm -rf $(TARGET) *.class *.html *.log *.aux *.out diff --git a/documents/c2-bezier-spline/minimal-document.tex b/documents/c2-bezier-spline/minimal-document.tex deleted file mode 100644 index 91d1d4c..0000000 --- a/documents/c2-bezier-spline/minimal-document.tex +++ /dev/null @@ -1,50 +0,0 @@ -\documentclass[a4paper]{scrartcl} -\usepackage[ngerman]{babel} -\usepackage[utf8]{inputenc} -\usepackage{amssymb,amsmath} - -\begin{document} - Wann ist ein kubischer Bezier-Splines $S(u) = [F(2 \cdot u), G(2(u-1))]$, - welche Kontrollpunkte in $\mathbb{R}^2$ haben, $C^2$-stetig? - - Sei im folgenden $a = P_0$, $b = P_1$, $c = P_2$, $d= P_3$. Dann gilt: - - \begin{align} - F(x) &= \sum_{i=0}^3 \mathbf{b}_i^n P_i\\ - &= \sum_{i=0}^3 \begin{pmatrix}n\\i\end{pmatrix} x^{i} (1-x)^{n-i} P_i\\ - &= (1-x)^3 P_0 + 3 x (1-x)^2 P_1 + 3 x^2 (1-x) P_2 + x^3 P_3\\ - &= -a x^3+3 a x^2-3 a x+a+3 b x^3-6 b x^2+3 b x-3 c x^3+3 c x^2+d x^3\\ - &= (-a + 3 b-3 c+d) x^3 + (3 a-6 b+3 c) x^2 + (-3 a+3 b) x + a\\ - F'(x)&= 3 (-a + 3 b-3 c+d) x^2 + 2 (3 a-6 b+3 c) x + (-3 a+3 b)\\ - F''(x) &= 6 (-a + 3 b-3 c+d) x + 2 (3 a-6 b+3 c) - \end{align} - - Damit $S$ nun $C^0$-stetig ist, muss $F(1) = G(0)$ gelten. Also: - - \begin{align} - G(0) &= F(1)\\ - \Leftrightarrow a_G - &= (-a_F + 3 b_F-3 c_F+d_F) + (3 a_F-6 b_F+3 c_F) + (-3 a_F+3 b_F) + (2+a_F)\\ - \Leftrightarrow a_G &= d_F\\ - \end{align} - - Damit $S$ nun $C^1$-stetig ist, muss zusätzlich $F'(1) = G'(0)$ gelten. Also: - - \begin{align} - G'(0) &= F'(1)\\ - \Leftrightarrow -3 a_G+3 b_G - &= 3 (-a_F + 3 b_F-3 c_F+d_F) + 2 (3 a_F-6 b_F+3 c_F) + (-3 a_F+3 b_F)\\ - \Leftrightarrow -3 (a_G-b_G) &= 3 (- c_F+d_F)\\ - \Leftrightarrow -a_G + b_G &= - c_F + d_F - \end{align} - - Damit $S$ nun $C^2$-stetig ist, muss zusätzlich $F''(1) = G''(0)$ gelten. Also: - - \begin{align} - G''(0) &= F''(1)\\ - \Leftrightarrow 2 (3 a_G-6 b_G+3 c_G) - &= 6 (-a_F + 3 b_F-3 c_F+d_F) + 2 (3 a_F-6 b_F+3 c_F)\\ - \Leftrightarrow 6 (a_G - 2 b_G + c_G) &= 6 (b_F-2 c_F+d_F)\\ - \Leftrightarrow a_G - 2 b_G + c_G &= b_F-2 c_F+d_F - \end{align} -\end{document}