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/*
* Copyright (c) 1999-2001 Eric Gourgoulhon
*
* This file is part of LORENE.
*
* LORENE is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* LORENE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with LORENE; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
char int1d_cheb_C[] = "$Header: /cvsroot/Lorene/C++/Source/Non_class_members/Operators/int1d_cheb.C,v 1.2 2014/10/13 08:53:23 j_novak Exp $" ;
/*
* Calcul de l'integrale
*
* int_-1^1 f(x) dx (1)
*
* pour une fonction f(x) donnee par ses coefficients de Tchebyshev
*
* f(x) = som_{i=0}^{nr-1} c_i T_{i}(x) (2)
*
* Entree:
* ------
* int nr : Nombre de coefficients de Tchebyshev dans le
* developpement (2)
* const double* cf : Tableau des nr coefficients c_i de la fonction
* definis par (2). Le stokage doit etre le suivant
* cf[i] = c_i 0 <= i <= nr - 1
* L'espace memoire correspondant au pointeur cf doit
* etre de taille au moins nr et doit avoir ete
* alloue avant l'appel a la routine
*
* Sortie (valeur de retour) :
* ------
* double int1d_cheb : Valeur de l'integrale (1)
*
*/
/*
* $Id: int1d_cheb.C,v 1.2 2014/10/13 08:53:23 j_novak Exp $
* $Log: int1d_cheb.C,v $
* Revision 1.2 2014/10/13 08:53:23 j_novak
* Lorene classes and functions now belong to the namespace Lorene.
*
* Revision 1.1 2005/02/16 15:27:55 m_forot
* *** empty log message ***
*
*
* $Header: /cvsroot/Lorene/C++/Source/Non_class_members/Operators/int1d_cheb.C,v 1.2 2014/10/13 08:53:23 j_novak Exp $
*
*/
namespace Lorene {
//*****************************************************************************
double int1d_cheb(int nr, const double* cf){
double som = - cf[0] ;
const double* cc = cf + 2 ;
for (int i=2; i<nr ; i=i+2) {
som += *cc / (i*i - 1) ;
cc = cc + 2 ;
}
return -2*som ;
}
}
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