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- /* sys/infnan.c
- *
- * Copyright (C) 2001, 2004, 2007 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 3 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 "gsl__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);
- }
- #else
- # if HAVE_DECL_ISFINITE
- int
- gsl_finite (const double x)
- {
- return isfinite(x);
- }
- # elif HAVE_DECL_FINITE
- int
- gsl_finite (const double x)
- {
- return finite(x);
- }
- # elif HAVE_IEEE_COMPARISONS
- int
- gsl_finite (const double x)
- {
- const double y = x - x;
- int status = (y == y);
- return status;
- }
- # endif
- # if HAVE_DECL_ISNAN
- int
- gsl_isnan (const double x)
- {
- return isnan(x);
- }
- #elif HAVE_IEEE_COMPARISONS
- int
- gsl_isnan (const double x)
- {
- int status = (x != x);
- return status;
- }
- # endif
- # if HAVE_DECL_ISINF
- int
- gsl_isinf (const double x)
- {
- return isinf(x);
- }
- # else
- int
- gsl_isinf (const double x)
- {
- if (! gsl_finite(x) && ! gsl_isnan(x))
- {
- return (x > 0 ? +1 : -1);
- }
- else
- {
- return 0;
- }
- }
- # endif
- #endif
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