1 /*$Id: m_divdiff.h,v 26.81 2008/05/27 05:34:00 al Exp $ -*- C++ -*-
2 * Copyright (C) 2001 Albert Davis
3 * Author: Albert Davis <aldavis@gnu.org>
4 *
5 * This file is part of "Gnucap", the Gnu Circuit Analysis Package
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 * 02110-1301, USA.
21 *------------------------------------------------------------------
22 * divided differences
23 * in:
24 * c = numerator (data points) (lost)
25 * t = denominator (time)
26 * n = size of array
27 * # of divided differences == n-1
28 * out:
29 * c = "divided differences" (mult by n! to get derivative)
30 */
31 //testing=script,complete 2006.07.13
32 /*--------------------------------------------------------------------------*/
33 #if 0
34 template<class T1, class T2>
35 inline void divided_differences(T1 c[], int n, const T2 t[])
36 {
37 untested();
38 for (int d=1; d<n; ++d) {
39 untested();
40 for (int i=n-1; i>=d; --i) {
41 untested();
42 c[i] = (c[i-1] - c[i]) / (t[i-d] - t[i]);
43 }
44 }
45 }
46 #endif
47 /*--------------------------------------------------------------------------*/
48 template<class T1, class T2>
derivatives(T1 c[],int n,const T2 t[])49 inline void derivatives(T1 c[], int n, const T2 t[])
50 {
51 for (int d=1; d<n; ++d) {
52 for (int i=n-1; i>=d; --i) {
53 c[i] = d * (c[i-1] - c[i]) / (t[i-d] - t[i]);
54 }
55 }
56 }
57 /*--------------------------------------------------------------------------*/
58 /*--------------------------------------------------------------------------*/
59