src/m_divdiff.h

   1 /*$Id: m_divdiff.h,v 1.1 2009-10-23 12:01:45 felix 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>
  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 // vim:ts=8:sw=2:noet: