summaryrefslogtreecommitdiffstats
blob: 40f6e14ba5e94aa338cfd1a23521e978762322a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
//  Copyright John Maddock 2005-2008.
//  Copyright (c) 2006-2008 Johan Rade
//  Use, modification and distribution are subject to the
//  Boost Software License, Version 1.0. (See accompanying file
//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_MATH_FPCLASSIFY_HPP
#define BOOST_MATH_FPCLASSIFY_HPP

#ifdef _MSC_VER
#pragma once
#endif

#include <math.h>
#include <boost/config/no_tr1/cmath.hpp>
#include <boost/limits.hpp>
#include <boost/math/tools/real_cast.hpp>
#include <boost/type_traits/is_floating_point.hpp>
#include <boost/math/special_functions/math_fwd.hpp>
#include <boost/math/special_functions/detail/fp_traits.hpp>
/*!
  \file fpclassify.hpp
  \brief Classify floating-point value as normal, subnormal, zero, infinite, or NaN.
  \version 1.0
  \author John Maddock
 */

/*

1. If the platform is C99 compliant, then the native floating point
classification functions are used.  However, note that we must only
define the functions which call std::fpclassify etc if that function
really does exist: otherwise a compiler may reject the code even though
the template is never instantiated.

2. If the platform is not C99 compliant, and the binary format for
a floating point type (float, double or long double) can be determined
at compile time, then the following algorithm is used:

        If all exponent bits, the flag bit (if there is one),
        and all significand bits are 0, then the number is zero.

        If all exponent bits and the flag bit (if there is one) are 0,
        and at least one significand bit is 1, then the number is subnormal.

        If all exponent bits are 1 and all significand bits are 0,
        then the number is infinity.

        If all exponent bits are 1 and at least one significand bit is 1,
        then the number is a not-a-number.

        Otherwise the number is normal.

        This algorithm works for the IEEE 754 representation,
        and also for several non IEEE 754 formats.

    Most formats have the structure
        sign bit + exponent bits + significand bits.

    A few have the structure
        sign bit + exponent bits + flag bit + significand bits.
    The flag bit is 0 for zero and subnormal numbers,
        and 1 for normal numbers and NaN.
        It is 0 (Motorola 68K) or 1 (Intel) for infinity.

    To get the bits, the four or eight most significant bytes are copied
    into an uint32_t or uint64_t and bit masks are applied.
    This covers all the exponent bits and the flag bit (if there is one),
    but not always all the significand bits.
    Some of the functions below have two implementations,
    depending on whether all the significand bits are copied or not.

3. If the platform is not C99 compliant, and the binary format for
a floating point type (float, double or long double) can not be determined
at compile time, then comparison with std::numeric_limits values
is used.

*/

#if defined(_MSC_VER) || defined(__BORLANDC__)
#include <float.h>
#endif

#ifdef BOOST_NO_STDC_NAMESPACE
  namespace std{ using ::abs; using ::fabs; }
#endif

namespace boost{

//
// This must not be located in any namespace under boost::math
// otherwise we can get into an infinite loop if isnan is
// a #define for "isnan" !
//
namespace math_detail{

#ifdef BOOST_MSVC
#pragma warning(push)
#pragma warning(disable:4800)
#endif

template <class T>
inline bool is_nan_helper(T t, const boost::true_type&)
{
#ifdef isnan
   return isnan(t);
#elif defined(BOOST_MATH_DISABLE_STD_FPCLASSIFY) || !defined(BOOST_HAS_FPCLASSIFY)
   (void)t;
   return false;
#else // BOOST_HAS_FPCLASSIFY
   return (BOOST_FPCLASSIFY_PREFIX fpclassify(t) == (int)FP_NAN);
#endif
}

#ifdef BOOST_MSVC
#pragma warning(pop)
#endif

template <class T>
inline bool is_nan_helper(T, const boost::false_type&)
{
   return false;
}

}

namespace math{

namespace detail{

#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
template <class T>
inline int fpclassify_imp BOOST_NO_MACRO_EXPAND(T t, const native_tag&)
{
   return (std::fpclassify)(t);
}
#endif

template <class T>
inline int fpclassify_imp BOOST_NO_MACRO_EXPAND(T t, const generic_tag<true>&)
{
   BOOST_MATH_INSTRUMENT_VARIABLE(t);

   // whenever possible check for Nan's first:
#if defined(BOOST_HAS_FPCLASSIFY)  && !defined(BOOST_MATH_DISABLE_STD_FPCLASSIFY)
   if(::boost::math_detail::is_nan_helper(t, ::boost::is_floating_point<T>()))
      return FP_NAN;
#elif defined(isnan)
   if(boost::math_detail::is_nan_helper(t, ::boost::is_floating_point<T>()))
      return FP_NAN;
#elif defined(_MSC_VER) || defined(__BORLANDC__)
   if(::_isnan(boost::math::tools::real_cast<double>(t)))
      return FP_NAN;
#endif
   // std::fabs broken on a few systems especially for long long!!!!
   T at = (t < T(0)) ? -t : t;

   // Use a process of exclusion to figure out
   // what kind of type we have, this relies on
   // IEEE conforming reals that will treat
   // Nan's as unordered.  Some compilers
   // don't do this once optimisations are
   // turned on, hence the check for nan's above.
   if(at <= (std::numeric_limits<T>::max)())
   {
      if(at >= (std::numeric_limits<T>::min)())
         return FP_NORMAL;
      return (at != 0) ? FP_SUBNORMAL : FP_ZERO;
   }
   else if(at > (std::numeric_limits<T>::max)())
      return FP_INFINITE;
   return FP_NAN;
}

template <class T>
inline int fpclassify_imp BOOST_NO_MACRO_EXPAND(T t, const generic_tag<false>&)
{
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
   if(std::numeric_limits<T>::is_specialized)
      return fpclassify_imp(t, generic_tag<true>());
#endif
   //
   // An unknown type with no numeric_limits support,
   // so what are we supposed to do we do here?
   //
   BOOST_MATH_INSTRUMENT_VARIABLE(t);

   return t == 0 ? FP_ZERO : FP_NORMAL;
}

template<class T>
int fpclassify_imp BOOST_NO_MACRO_EXPAND(T x, ieee_copy_all_bits_tag)
{
   typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;

   BOOST_MATH_INSTRUMENT_VARIABLE(x);

   BOOST_DEDUCED_TYPENAME traits::bits a;
   traits::get_bits(x,a);
   BOOST_MATH_INSTRUMENT_VARIABLE(a);
   a &= traits::exponent | traits::flag | traits::significand;
   BOOST_MATH_INSTRUMENT_VARIABLE((traits::exponent | traits::flag | traits::significand));
   BOOST_MATH_INSTRUMENT_VARIABLE(a);

   if(a <= traits::significand) {
      if(a == 0)
         return FP_ZERO;
      else
         return FP_SUBNORMAL;
   }

   if(a < traits::exponent) return FP_NORMAL;

   a &= traits::significand;
   if(a == 0) return FP_INFINITE;

   return FP_NAN;
}

template<class T>
int fpclassify_imp BOOST_NO_MACRO_EXPAND(T x, ieee_copy_leading_bits_tag)
{
   typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;

   BOOST_MATH_INSTRUMENT_VARIABLE(x);

   BOOST_DEDUCED_TYPENAME traits::bits a;
   traits::get_bits(x,a);
   a &= traits::exponent | traits::flag | traits::significand;

   if(a <= traits::significand) {
      if(x == 0)
         return FP_ZERO;
      else
         return FP_SUBNORMAL;
   }

   if(a < traits::exponent) return FP_NORMAL;

   a &= traits::significand;
   traits::set_bits(x,a);
   if(x == 0) return FP_INFINITE;

   return FP_NAN;
}

#if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && (defined(BOOST_MATH_NO_NATIVE_LONG_DOUBLE_FP_CLASSIFY) || defined(BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS))
inline int fpclassify_imp BOOST_NO_MACRO_EXPAND(long double t, const native_tag&)
{
   return boost::math::detail::fpclassify_imp(t, generic_tag<true>());
}
#endif

}  // namespace detail

template <class T>
inline int fpclassify BOOST_NO_MACRO_EXPAND(T t)
{
   typedef typename detail::fp_traits<T>::type traits;
   typedef typename traits::method method;
   typedef typename tools::promote_args_permissive<T>::type value_type;
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
   if(std::numeric_limits<T>::is_specialized && detail::is_generic_tag_false(static_cast<method*>(0)))
      return detail::fpclassify_imp(static_cast<value_type>(t), detail::generic_tag<true>());
   return detail::fpclassify_imp(static_cast<value_type>(t), method());
#else
   return detail::fpclassify_imp(static_cast<value_type>(t), method());
#endif
}

#ifdef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
template <>
inline int fpclassify<long double> BOOST_NO_MACRO_EXPAND(long double t)
{
   typedef detail::fp_traits<long double>::type traits;
   typedef traits::method method;
   typedef long double value_type;
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
   if(std::numeric_limits<long double>::is_specialized && detail::is_generic_tag_false(static_cast<method*>(0)))
      return detail::fpclassify_imp(static_cast<value_type>(t), detail::generic_tag<true>());
   return detail::fpclassify_imp(static_cast<value_type>(t), method());
#else
   return detail::fpclassify_imp(static_cast<value_type>(t), method());
#endif
}
#endif

namespace detail {

#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
    template<class T>
    inline bool isfinite_impl(T x, native_tag const&)
    {
        return (std::isfinite)(x);
    }
#endif

    template<class T>
    inline bool isfinite_impl(T x, generic_tag<true> const&)
    {
        return x >= -(std::numeric_limits<T>::max)()
            && x <= (std::numeric_limits<T>::max)();
    }

    template<class T>
    inline bool isfinite_impl(T x, generic_tag<false> const&)
    {
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
      if(std::numeric_limits<T>::is_specialized)
         return isfinite_impl(x, generic_tag<true>());
#endif
       (void)x; // warning supression.
       return true;
    }

    template<class T>
    inline bool isfinite_impl(T x, ieee_tag const&)
    {
        typedef BOOST_DEDUCED_TYPENAME detail::fp_traits<T>::type traits;
        BOOST_DEDUCED_TYPENAME traits::bits a;
        traits::get_bits(x,a);
        a &= traits::exponent;
        return a != traits::exponent;
    }

#if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && defined(BOOST_MATH_NO_NATIVE_LONG_DOUBLE_FP_CLASSIFY)
inline bool isfinite_impl BOOST_NO_MACRO_EXPAND(long double t, const native_tag&)
{
   return boost::math::detail::isfinite_impl(t, generic_tag<true>());
}
#endif

}

template<class T>
inline bool (isfinite)(T x)
{ //!< \brief return true if floating-point type t is finite.
   typedef typename detail::fp_traits<T>::type traits;
   typedef typename traits::method method;
   // typedef typename boost::is_floating_point<T>::type fp_tag;
   typedef typename tools::promote_args_permissive<T>::type value_type;
   return detail::isfinite_impl(static_cast<value_type>(x), method());
}

#ifdef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
template<>
inline bool (isfinite)(long double x)
{ //!< \brief return true if floating-point type t is finite.
   typedef detail::fp_traits<long double>::type traits;
   typedef traits::method method;
   //typedef boost::is_floating_point<long double>::type fp_tag;
   typedef long double value_type;
   return detail::isfinite_impl(static_cast<value_type>(x), method());
}
#endif

//------------------------------------------------------------------------------

namespace detail {

#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
    template<class T>
    inline bool isnormal_impl(T x, native_tag const&)
    {
        return (std::isnormal)(x);
    }
#endif

    template<class T>
    inline bool isnormal_impl(T x, generic_tag<true> const&)
    {
        if(x < 0) x = -x;
        return x >= (std::numeric_limits<T>::min)()
            && x <= (std::numeric_limits<T>::max)();
    }

    template<class T>
    inline bool isnormal_impl(T x, generic_tag<false> const&)
    {
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
      if(std::numeric_limits<T>::is_specialized)
         return isnormal_impl(x, generic_tag<true>());
#endif
       return !(x == 0);
    }

    template<class T>
    inline bool isnormal_impl(T x, ieee_tag const&)
    {
        typedef BOOST_DEDUCED_TYPENAME detail::fp_traits<T>::type traits;
        BOOST_DEDUCED_TYPENAME traits::bits a;
        traits::get_bits(x,a);
        a &= traits::exponent | traits::flag;
        return (a != 0) && (a < traits::exponent);
    }

#if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && defined(BOOST_MATH_NO_NATIVE_LONG_DOUBLE_FP_CLASSIFY)
inline bool isnormal_impl BOOST_NO_MACRO_EXPAND(long double t, const native_tag&)
{
   return boost::math::detail::isnormal_impl(t, generic_tag<true>());
}
#endif

}

template<class T>
inline bool (isnormal)(T x)
{
   typedef typename detail::fp_traits<T>::type traits;
   typedef typename traits::method method;
   //typedef typename boost::is_floating_point<T>::type fp_tag;
   typedef typename tools::promote_args_permissive<T>::type value_type;
   return detail::isnormal_impl(static_cast<value_type>(x), method());
}

#ifdef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
template<>
inline bool (isnormal)(long double x)
{
   typedef detail::fp_traits<long double>::type traits;
   typedef traits::method method;
   //typedef boost::is_floating_point<long double>::type fp_tag;
   typedef long double value_type;
   return detail::isnormal_impl(static_cast<value_type>(x), method());
}
#endif

//------------------------------------------------------------------------------

namespace detail {

#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
    template<class T>
    inline bool isinf_impl(T x, native_tag const&)
    {
        return (std::isinf)(x);
    }
#endif

    template<class T>
    inline bool isinf_impl(T x, generic_tag<true> const&)
    {
        (void)x; // in case the compiler thinks that x is unused because std::numeric_limits<T>::has_infinity is false
        return std::numeric_limits<T>::has_infinity
            && ( x == std::numeric_limits<T>::infinity()
                 || x == -std::numeric_limits<T>::infinity());
    }

    template<class T>
    inline bool isinf_impl(T x, generic_tag<false> const&)
    {
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
      if(std::numeric_limits<T>::is_specialized)
         return isinf_impl(x, generic_tag<true>());
#endif
        (void)x; // warning supression.
        return false;
    }

    template<class T>
    inline bool isinf_impl(T x, ieee_copy_all_bits_tag const&)
    {
        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;

        BOOST_DEDUCED_TYPENAME traits::bits a;
        traits::get_bits(x,a);
        a &= traits::exponent | traits::significand;
        return a == traits::exponent;
    }

    template<class T>
    inline bool isinf_impl(T x, ieee_copy_leading_bits_tag const&)
    {
        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;

        BOOST_DEDUCED_TYPENAME traits::bits a;
        traits::get_bits(x,a);
        a &= traits::exponent | traits::significand;
        if(a != traits::exponent)
            return false;

        traits::set_bits(x,0);
        return x == 0;
    }

#if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && defined(BOOST_MATH_NO_NATIVE_LONG_DOUBLE_FP_CLASSIFY)
inline bool isinf_impl BOOST_NO_MACRO_EXPAND(long double t, const native_tag&)
{
   return boost::math::detail::isinf_impl(t, generic_tag<true>());
}
#endif

}   // namespace detail

template<class T>
inline bool (isinf)(T x)
{
   typedef typename detail::fp_traits<T>::type traits;
   typedef typename traits::method method;
   // typedef typename boost::is_floating_point<T>::type fp_tag;
   typedef typename tools::promote_args_permissive<T>::type value_type;
   return detail::isinf_impl(static_cast<value_type>(x), method());
}

#ifdef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
template<>
inline bool (isinf)(long double x)
{
   typedef detail::fp_traits<long double>::type traits;
   typedef traits::method method;
   //typedef boost::is_floating_point<long double>::type fp_tag;
   typedef long double value_type;
   return detail::isinf_impl(static_cast<value_type>(x), method());
}
#endif

//------------------------------------------------------------------------------

namespace detail {

#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
    template<class T>
    inline bool isnan_impl(T x, native_tag const&)
    {
        return (std::isnan)(x);
    }
#endif

    template<class T>
    inline bool isnan_impl(T x, generic_tag<true> const&)
    {
        return std::numeric_limits<T>::has_infinity
            ? !(x <= std::numeric_limits<T>::infinity())
            : x != x;
    }

    template<class T>
    inline bool isnan_impl(T x, generic_tag<false> const&)
    {
#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
      if(std::numeric_limits<T>::is_specialized)
         return isnan_impl(x, generic_tag<true>());
#endif
        (void)x; // warning supression
        return false;
    }

    template<class T>
    inline bool isnan_impl(T x, ieee_copy_all_bits_tag const&)
    {
        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;

        BOOST_DEDUCED_TYPENAME traits::bits a;
        traits::get_bits(x,a);
        a &= traits::exponent | traits::significand;
        return a > traits::exponent;
    }

    template<class T>
    inline bool isnan_impl(T x, ieee_copy_leading_bits_tag const&)
    {
        typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;

        BOOST_DEDUCED_TYPENAME traits::bits a;
        traits::get_bits(x,a);

        a &= traits::exponent | traits::significand;
        if(a < traits::exponent)
            return false;

        a &= traits::significand;
        traits::set_bits(x,a);
        return x != 0;
    }

}   // namespace detail

template<class T>
inline bool (isnan)(T x)
{ //!< \brief return true if floating-point type t is NaN (Not A Number).
   typedef typename detail::fp_traits<T>::type traits;
   typedef typename traits::method method;
   // typedef typename boost::is_floating_point<T>::type fp_tag;
   return detail::isnan_impl(x, method());
}

#ifdef isnan
template <> inline bool isnan BOOST_NO_MACRO_EXPAND<float>(float t){ return ::boost::math_detail::is_nan_helper(t, boost::true_type()); }
template <> inline bool isnan BOOST_NO_MACRO_EXPAND<double>(double t){ return ::boost::math_detail::is_nan_helper(t, boost::true_type()); }
template <> inline bool isnan BOOST_NO_MACRO_EXPAND<long double>(long double t){ return ::boost::math_detail::is_nan_helper(t, boost::true_type()); }
#elif defined(BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS)
template<>
inline bool (isnan)(long double x)
{ //!< \brief return true if floating-point type t is NaN (Not A Number).
   typedef detail::fp_traits<long double>::type traits;
   typedef traits::method method;
   //typedef boost::is_floating_point<long double>::type fp_tag;
   return detail::isnan_impl(x, method());
}
#endif

} // namespace math
} // namespace boost

#endif // BOOST_MATH_FPCLASSIFY_HPP