1 /* integration/err.c 2 * 3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 3 of the License, or (at 8 * your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, but 11 * WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 * General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 18 */ 19 20 #include "gsl__config.h" 21 #include <math.h> 22 #include <float.h> 23 #include "gsl_math.h" 24 #include "gsl_integration.h" 25 26 static double rescale_error (double err, const double result_abs, const double result_asc) ; 27 28 static double 29 rescale_error (double err, const double result_abs, const double result_asc) 30 { 31 err = fabs(err) ; 32 33 if (result_asc != 0 && err != 0) 34 { 35 double scale = pow((200 * err / result_asc), 1.5) ; 36 37 if (scale < 1) 38 { 39 err = result_asc * scale ; 40 } 41 else 42 { 43 err = result_asc ; 44 } 45 } 46 if (result_abs > GSL_DBL_MIN / (50 * GSL_DBL_EPSILON)) 47 { 48 double min_err = 50 * GSL_DBL_EPSILON * result_abs ; 49 50 if (min_err > err) 51 { 52 err = min_err ; 53 } 54 } 55 56 return err ; 57 } 58 59