3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough
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.
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.
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.
21 #include <gsl/gsl_math.h>
22 #include <gsl/gsl_errno.h>
23 #include <gsl/gsl_min.h>
26 gsl_min_test_interval (double x_lower, double x_upper, double epsabs, double epsrel)
28 const double lower = x_lower;
29 const double upper = x_upper;
31 const double abs_lower = fabs(lower) ;
32 const double abs_upper = fabs(upper) ;
34 double min_abs, tolerance;
37 GSL_ERROR ("relative tolerance is negative", GSL_EBADTOL);
40 GSL_ERROR ("absolute tolerance is negative", GSL_EBADTOL);
43 GSL_ERROR ("lower bound larger than upper_bound", GSL_EINVAL);
45 if ((lower > 0 && upper > 0) || (lower < 0 && upper < 0))
47 min_abs = GSL_MIN_DBL(abs_lower, abs_upper) ;
54 tolerance = epsabs + epsrel * min_abs ;
56 if (fabs(upper - lower) < tolerance)