| /* sys/infnan.c |
| * |
| * Copyright (C) 2001, 2004 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 <math.h> |
| |
| #if HAVE_IEEEFP_H |
| #include <ieeefp.h> |
| #endif |
| |
| double gsl_nan (void); |
| double gsl_posinf (void); |
| double gsl_neginf (void); |
| double gsl_fdiv (const double x, const double y); |
| |
| double gsl_nan (void) |
| { |
| return gsl_fdiv (0.0, 0.0); |
| } |
| |
| double gsl_posinf (void) |
| { |
| return gsl_fdiv (+1.0, 0.0); |
| } |
| |
| double gsl_neginf (void) |
| { |
| return gsl_fdiv (-1.0, 0.0); |
| } |
| |
| |
| int gsl_isnan (const double x); |
| int gsl_isinf (const double x); |
| int gsl_finite (const double x); |
| |
| #if defined(_MSC_VER) /* Microsoft Visual C++ */ |
| #include <float.h> |
| int |
| gsl_isnan (const double x) |
| { |
| return _isnan(x); |
| } |
| |
| int |
| gsl_isinf (const double x) |
| { |
| int fpc = _fpclass(x); |
| |
| if (fpc == _FPCLASS_PINF) |
| return +1; |
| else if (fpc == _FPCLASS_NINF) |
| return -1; |
| else |
| return 0; |
| } |
| |
| int |
| gsl_finite (const double x) |
| { |
| return _finite(x); |
| } |
| #elif HAVE_IEEE_COMPARISONS |
| int |
| gsl_isnan (const double x) |
| { |
| int status = (x != x); |
| return status; |
| } |
| |
| int |
| gsl_isinf (const double x) |
| { |
| double y = x - x; |
| int s = (y != y); |
| |
| if (s && x > 0) |
| return +1; |
| else if (s && x < 0) |
| return -1; |
| else |
| return 0; |
| } |
| |
| int |
| gsl_finite (const double x) |
| { |
| const double y = x - x; |
| int status = (y == y); |
| return status; |
| } |
| #else |
| |
| #if HAVE_DECL_ISNAN |
| int |
| gsl_isnan (const double x) |
| { |
| return isnan(x); |
| } |
| #endif |
| |
| #if HAVE_DECL_ISINF |
| int |
| gsl_isinf (const double x) |
| { |
| return isinf(x); |
| } |
| #else |
| int |
| gsl_isinf (const double x) |
| { |
| return (! gsl_finite(x)) && (! gsl_isnan(x)); |
| } |
| #endif |
| |
| |
| #if HAVE_DECL_FINITE |
| int |
| gsl_finite (const double x) |
| { |
| return finite(x); |
| } |
| #elif HAVE_DECL_ISFINITE |
| int |
| gsl_finite (const double x) |
| { |
| return isfinite(x); |
| } |
| #endif |
| |
| #endif |
| |