| /* roots/convergence.c |
| * |
| * Copyright (C) 1996, 1997, 1998, 1999, 2000 Reid Priedhorsky, Brian Gough |
| * |
| * This program 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. |
| * |
| * This program 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 this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| */ |
| |
| #include <config.h> |
| #include <gsl/gsl_math.h> |
| #include <gsl/gsl_errno.h> |
| #include <gsl/gsl_roots.h> |
| |
| int |
| gsl_root_test_interval (double x_lower, double x_upper, double epsabs, double epsrel) |
| { |
| const double abs_lower = fabs(x_lower) ; |
| const double abs_upper = fabs(x_upper) ; |
| |
| double min_abs, tolerance; |
| |
| if (epsrel < 0.0) |
| GSL_ERROR ("relative tolerance is negative", GSL_EBADTOL); |
| |
| if (epsabs < 0.0) |
| GSL_ERROR ("absolute tolerance is negative", GSL_EBADTOL); |
| |
| if (x_lower > x_upper) |
| GSL_ERROR ("lower bound larger than upper bound", GSL_EINVAL); |
| |
| if ((x_lower > 0.0 && x_upper > 0.0) || (x_lower < 0.0 && x_upper < 0.0)) |
| { |
| min_abs = GSL_MIN_DBL(abs_lower, abs_upper) ; |
| } |
| else |
| { |
| min_abs = 0; |
| } |
| |
| tolerance = epsabs + epsrel * min_abs ; |
| |
| if (fabs(x_upper - x_lower) < tolerance) |
| return GSL_SUCCESS; |
| |
| return GSL_CONTINUE ; |
| } |
| |
| int |
| gsl_root_test_delta (double x1, double x0, double epsabs, double epsrel) |
| { |
| const double tolerance = epsabs + epsrel * fabs(x1) ; |
| |
| if (epsrel < 0.0) |
| GSL_ERROR ("relative tolerance is negative", GSL_EBADTOL); |
| |
| if (epsabs < 0.0) |
| GSL_ERROR ("absolute tolerance is negative", GSL_EBADTOL); |
| |
| if (fabs(x1 - x0) < tolerance || x1 == x0) |
| return GSL_SUCCESS; |
| |
| return GSL_CONTINUE ; |
| } |
| |
| int |
| gsl_root_test_residual (double f, double epsabs) |
| { |
| if (epsabs < 0.0) |
| GSL_ERROR ("absolute tolerance is negative", GSL_EBADTOL); |
| |
| if (fabs(f) < epsabs) |
| return GSL_SUCCESS; |
| |
| return GSL_CONTINUE ; |
| } |
| |