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Half.h
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//
// SPDX-License-Identifier: BSD-3-Clause
// Copyright Contributors to the OpenEXR Project.
//
//
// Primary original authors:
// Florian Kainz <kainz@ilm.com>
// Rod Bogart <rgb@ilm.com>
//
#ifndef OPENVDB_MATH_HALF_HAS_BEEN_INCLUDED
#define OPENVDB_MATH_HALF_HAS_BEEN_INCLUDED
/// @file half.h
/// The half type is a 16-bit floating number, compatible with the
/// IEEE 754-2008 binary16 type.
///
/// **Representation of a 32-bit float:**
///
/// We assume that a float, f, is an IEEE 754 single-precision
/// floating point number, whose bits are arranged as follows:
///
/// 31 (msb)
/// |
/// | 30 23
/// | | |
/// | | | 22 0 (lsb)
/// | | | | |
/// X XXXXXXXX XXXXXXXXXXXXXXXXXXXXXXX
///
/// s e m
///
/// S is the sign-bit, e is the exponent and m is the significand.
///
/// If e is between 1 and 254, f is a normalized number:
///
/// s e-127
/// f = (-1) * 2 * 1.m
///
/// If e is 0, and m is not zero, f is a denormalized number:
///
/// s -126
/// f = (-1) * 2 * 0.m
///
/// If e and m are both zero, f is zero:
///
/// f = 0.0
///
/// If e is 255, f is an "infinity" or "not a number" (NAN),
/// depending on whether m is zero or not.
///
/// Examples:
///
/// 0 00000000 00000000000000000000000 = 0.0
/// 0 01111110 00000000000000000000000 = 0.5
/// 0 01111111 00000000000000000000000 = 1.0
/// 0 10000000 00000000000000000000000 = 2.0
/// 0 10000000 10000000000000000000000 = 3.0
/// 1 10000101 11110000010000000000000 = -124.0625
/// 0 11111111 00000000000000000000000 = +infinity
/// 1 11111111 00000000000000000000000 = -infinity
/// 0 11111111 10000000000000000000000 = NAN
/// 1 11111111 11111111111111111111111 = NAN
///
/// **Representation of a 16-bit half:**
///
/// Here is the bit-layout for a half number, h:
///
/// 15 (msb)
/// |
/// | 14 10
/// | | |
/// | | | 9 0 (lsb)
/// | | | | |
/// X XXXXX XXXXXXXXXX
///
/// s e m
///
/// S is the sign-bit, e is the exponent and m is the significand.
///
/// If e is between 1 and 30, h is a normalized number:
///
/// s e-15
/// h = (-1) * 2 * 1.m
///
/// If e is 0, and m is not zero, h is a denormalized number:
///
/// S -14
/// h = (-1) * 2 * 0.m
///
/// If e and m are both zero, h is zero:
///
/// h = 0.0
///
/// If e is 31, h is an "infinity" or "not a number" (NAN),
/// depending on whether m is zero or not.
///
/// Examples:
///
/// 0 00000 0000000000 = 0.0
/// 0 01110 0000000000 = 0.5
/// 0 01111 0000000000 = 1.0
/// 0 10000 0000000000 = 2.0
/// 0 10000 1000000000 = 3.0
/// 1 10101 1111000001 = -124.0625
/// 0 11111 0000000000 = +infinity
/// 1 11111 0000000000 = -infinity
/// 0 11111 1000000000 = NAN
/// 1 11111 1111111111 = NAN
///
/// **Conversion via Lookup Table:**
///
/// Converting from half to float is performed by default using a
/// lookup table. There are only 65,536 different half numbers; each
/// of these numbers has been converted and stored in a table pointed
/// to by the ``imath_half_to_float_table`` pointer.
///
/// Prior to Imath v3.1, conversion from float to half was
/// accomplished with the help of an exponent look table, but this is
/// now replaced with explicit bit shifting.
///
/// **Conversion via Hardware:**
///
/// For Imath v3.1, the conversion routines have been extended to use
/// F16C SSE instructions whenever present and enabled by compiler
/// flags.
///
/// **Conversion via Bit-Shifting**
///
/// If F16C SSE instructions are not available, conversion can be
/// accomplished by a bit-shifting algorithm. For half-to-float
/// conversion, this is generally slower than the lookup table, but it
/// may be preferable when memory limits preclude storing of the
/// 65,536-entry lookup table.
///
/// The lookup table symbol is included in the compilation even if
/// ``IMATH_HALF_USE_LOOKUP_TABLE`` is false, because application code
/// using the exported ``half.h`` may choose to enable the use of the table.
///
/// An implementation can eliminate the table from compilation by
/// defining the ``IMATH_HALF_NO_LOOKUP_TABLE`` preprocessor symbol.
/// Simply add:
///
/// #define IMATH_HALF_NO_LOOKUP_TABLE
///
/// before including ``half.h``, or define the symbol on the compile
/// command line.
///
/// Furthermore, an implementation wishing to receive ``FE_OVERFLOW``
/// and ``FE_UNDERFLOW`` floating point exceptions when converting
/// float to half by the bit-shift algorithm can define the
/// preprocessor symbol ``IMATH_HALF_ENABLE_FP_EXCEPTIONS`` prior to
/// including ``half.h``:
///
/// #define IMATH_HALF_ENABLE_FP_EXCEPTIONS
///
/// **Conversion Performance Comparison:**
///
/// Testing on a Core i9, the timings are approximately:
///
/// half to float
/// - table: 0.71 ns / call
/// - no table: 1.06 ns / call
/// - f16c: 0.45 ns / call
///
/// float-to-half:
/// - original: 5.2 ns / call
/// - no exp table + opt: 1.27 ns / call
/// - f16c: 0.45 ns / call
///
/// **Note:** the timing above depends on the distribution of the
/// floats in question.
///
#include <openvdb/Platform.h>
#include <openvdb/version.h>
#include <iostream>
OPENVDB_NO_TYPE_CONVERSION_WARNING_BEGIN
#if defined(_WIN32)
#include <intrin.h>
#elif defined(__x86_64__)
#include <x86intrin.h>
#elif defined(__F16C__)
#include <immintrin.h>
#endif
#include <stdint.h>
#include <stdio.h>
#ifdef IMATH_HALF_ENABLE_FP_EXCEPTIONS
#include <fenv.h>
#endif
namespace openvdb {
OPENVDB_USE_VERSION_NAMESPACE
namespace OPENVDB_VERSION_NAME {
namespace math {
namespace internal {
// Use of lookup table is explicitly suppressed and the generation of
// a lookup table is suppressed. This is required because we namespace
// our type, but the lookup table is extern "C" and lacks a namespace.
// Thus any attempt to link two versions of OpenVDB with different
// namespaces will clash due to redefinition with a new type.
// The default was not to use a lookup table.
#undef IMATH_HALF_USE_LOOKUP_TABLE
#define IMATH_HALF_NO_LOOKUP_TABLE
//-------------------------------------------------------------------------
// Limits
//
// Visual C++ will complain if VDBB_HALF_DENORM_MIN, VDB_HALF_NRM_MIN etc. are not float
// constants, but at least one other compiler (gcc 2.96) produces incorrect
// results if they are.
//-------------------------------------------------------------------------
#if (defined _WIN32 || defined _WIN64) && defined _MSC_VER
/// Smallest positive denormalized half
#define VDBB_HALF_DENORM_MIN 5.96046448e-08f
/// Smallest positive normalized half
#define VDB_HALF_NRM_MIN 6.10351562e-05f
/// Smallest positive normalized half
#define VDB_HALF_MIN 6.10351562e-05f
/// Largest positive half
#define VDB_HALF_MAX 65504.0f
/// Smallest positive e for which ``half(1.0 + e) != half(1.0)``
#define VDB_HALF_EPSILON 0.00097656f
#else
/// Smallest positive denormalized half
#define VDBB_HALF_DENORM_MIN 5.96046448e-08
/// Smallest positive normalized half
#define VDB_HALF_NRM_MIN 6.10351562e-05
/// Smallest positive normalized half
#define VDB_HALF_MIN 6.10351562e-05f
/// Largest positive half
#define VDB_HALF_MAX 65504.0
/// Smallest positive e for which ``half(1.0 + e) != half(1.0)``
#define VDB_HALF_EPSILON 0.00097656
#endif
/// Number of digits in mantissa (significand + hidden leading 1)
#define VDB_HALF_MANT_DIG 11
/// Number of base 10 digits that can be represented without change:
///
/// ``floor( (HALF_MANT_DIG - 1) * log10(2) ) => 3.01... -> 3``
#define VDB_HALF_DIG 3
/// Number of base-10 digits that are necessary to uniquely represent
/// all distinct values:
///
/// ``ceil(HALF_MANT_DIG * log10(2) + 1) => 4.31... -> 5``
#define VDB_HALF_DECIMAL_DIG 5
/// Base of the exponent
#define VDB_HALF_RADIX 2
/// Minimum negative integer such that ``HALF_RADIX`` raised to the power
/// of one less than that integer is a normalized half
#define VDBB_HALF_DENORM_MIN_EXP -13
/// Maximum positive integer such that ``HALF_RADIX`` raised to the power
/// of one less than that integer is a normalized half
#define VDB_HALF_MAX_EXP 16
/// Minimum positive integer such that 10 raised to that power is a
/// normalized half
#define VDBB_HALF_DENORM_MIN_10_EXP -4
/// Maximum positive integer such that 10 raised to that power is a
/// normalized half
#define VDB_HALF_MAX_10_EXP 4
/// a type for both C-only programs and C++ to use the same utilities
typedef union imath_half_uif
{
uint32_t i;
float f;
} imath_half_uif_t;
/// a type for both C-only programs and C++ to use the same utilities
typedef uint16_t imath_half_bits_t;
#if !defined(__cplusplus) && !defined(__CUDACC__)
/// if we're in a C-only context, alias the half bits type to half
typedef imath_half_bits_t half;
#endif
#if !defined(IMATH_HALF_NO_LOOKUP_TABLE)
#if defined(__cplusplus)
extern "C"
#else
extern
#endif
OPENVDB_API const imath_half_uif_t* imath_half_to_float_table;
#endif
///
/// Convert half to float
///
static inline float
imath_half_to_float (imath_half_bits_t h)
{
#if defined(__F16C__)
// NB: The intel implementation does seem to treat NaN slightly
// different than the original toFloat table does (i.e. where the
// 1 bits are, meaning the signalling or not bits). This seems
// benign, given that the original library didn't really deal with
// signalling vs non-signalling NaNs
# ifdef _MSC_VER
/* msvc does not seem to have cvtsh_ss :( */
return _mm_cvtss_f32 (_mm_cvtph_ps (_mm_set1_epi16 (h)));
# else
return _cvtsh_ss (h);
# endif
#elif defined(IMATH_HALF_USE_LOOKUP_TABLE) && !defined(IMATH_HALF_NO_LOOKUP_TABLE)
return imath_half_to_float_table[h].f;
#else
imath_half_uif_t v;
// this code would be clearer, although it does appear to be faster
// (1.06 vs 1.08 ns/call) to avoid the constants and just do 4
// shifts.
//
uint32_t hexpmant = ( (uint32_t)(h) << 17 ) >> 4;
v.i = ((uint32_t)(h >> 15)) << 31;
// the likely really does help if most of your numbers are "normal" half numbers
if (OPENVDB_LIKELY ((hexpmant >= 0x00800000)))
{
v.i |= hexpmant;
// either we are a normal number, in which case add in the bias difference
// otherwise make sure all exponent bits are set
if (OPENVDB_LIKELY ((hexpmant < 0x0f800000)))
v.i += 0x38000000;
else
v.i |= 0x7f800000;
}
else if (hexpmant != 0)
{
// exponent is 0 because we're denormal, don't have to extract
// the mantissa, can just use as is
//
//
// other compilers may provide count-leading-zeros primitives,
// but we need the community to inform us of the variants
uint32_t lc;
# if defined(_MSC_VER) && (_M_IX86 || _M_X64)
lc = __lzcnt (hexpmant);
# elif defined(__GNUC__) || defined(__clang__)
lc = (uint32_t) __builtin_clz (hexpmant);
# else
lc = 0;
while (0 == ((hexpmant << lc) & 0x80000000))
++lc;
# endif
lc -= 8;
// so nominally we want to remove that extra bit we shifted
// up, but we are going to add that bit back in, then subtract
// from it with the 0x38800000 - (lc << 23)....
//
// by combining, this allows us to skip the & operation (and
// remove a constant)
//
// hexpmant &= ~0x00800000;
v.i |= 0x38800000;
// lc is now x, where the desired exponent is then
// -14 - lc
// + 127 -> new exponent
v.i |= (hexpmant << lc);
v.i -= (lc << 23);
}
return v.f;
#endif
}
///
/// Convert half to float
///
/// Note: This only supports the "round to even" rounding mode, which
/// was the only mode supported by the original OpenEXR library
///
static inline imath_half_bits_t
imath_float_to_half (float f)
{
#if defined(__F16C__)
# ifdef _MSC_VER
// msvc does not seem to have cvtsh_ss :(
return _mm_extract_epi16 (
_mm_cvtps_ph (_mm_set_ss (f), (_MM_FROUND_TO_NEAREST_INT | _MM_FROUND_NO_EXC)),
0);
# else
// preserve the fixed rounding mode to nearest
return _cvtss_sh (f, (_MM_FROUND_TO_NEAREST_INT | _MM_FROUND_NO_EXC));
# endif
#else
imath_half_uif_t v;
imath_half_bits_t ret;
uint32_t e, m, ui, r, shift;
v.f = f;
ui = (v.i & ~0x80000000);
ret = ((v.i >> 16) & 0x8000);
// exponent large enough to result in a normal number, round and return
if (ui >= 0x38800000)
{
// inf or nan
if (OPENVDB_UNLIKELY (ui >= 0x7f800000))
{
ret |= 0x7c00;
if (ui == 0x7f800000)
return ret;
m = (ui & 0x7fffff) >> 13;
// make sure we have at least one bit after shift to preserve nan-ness
return ret | (uint16_t)m | (uint16_t)(m == 0);
}
// too large, round to infinity
if (OPENVDB_UNLIKELY (ui > 0x477fefff))
{
# ifdef IMATH_HALF_ENABLE_FP_EXCEPTIONS
feraiseexcept (FE_OVERFLOW);
# endif
return ret | 0x7c00;
}
ui -= 0x38000000;
ui = ((ui + 0x00000fff + ((ui >> 13) & 1)) >> 13);
return ret | (uint16_t)ui;
}
// zero or flush to 0
if (ui < 0x33000001)
{
# ifdef IMATH_HALF_ENABLE_FP_EXCEPTIONS
if (ui == 0)
return ret;
feraiseexcept (FE_UNDERFLOW);
# endif
return ret;
}
// produce a denormalized half
e = (ui >> 23);
shift = 0x7e - e;
m = 0x800000 | (ui & 0x7fffff);
r = m << (32 - shift);
ret |= (m >> shift);
if (r > 0x80000000 || (r == 0x80000000 && (ret & 0x1) != 0))
++ret;
return ret;
#endif
}
////////////////////////////////////////
///
///
/// class half -- 16-bit floating point number
///
/// Type half can represent positive and negative numbers whose
/// magnitude is between roughly 6.1e-5 and 6.5e+4 with a relative
/// error of 9.8e-4; numbers smaller than 6.1e-5 can be represented
/// with an absolute error of 6.0e-8. All integers from -2048 to
/// +2048 can be represented exactly.
///
/// Type half behaves (almost) like the built-in C++ floating point
/// types. In arithmetic expressions, half, float and double can be
/// mixed freely. Here are a few examples:
///
/// half a (3.5);
/// float b (a + sqrt (a));
/// a += b;
/// b += a;
/// b = a + 7;
///
/// Conversions from half to float are lossless; all half numbers
/// are exactly representable as floats.
///
/// Conversions from float to half may not preserve a float's value
/// exactly. If a float is not representable as a half, then the
/// float value is rounded to the nearest representable half. If a
/// float value is exactly in the middle between the two closest
/// representable half values, then the float value is rounded to
/// the closest half whose least significant bit is zero.
///
/// Overflows during float-to-half conversions cause arithmetic
/// exceptions. An overflow occurs when the float value to be
/// converted is too large to be represented as a half, or if the
/// float value is an infinity or a NAN.
///
/// The implementation of type half makes the following assumptions
/// about the implementation of the built-in C++ types:
///
/// * float is an IEEE 754 single-precision number
/// * sizeof (float) == 4
/// * sizeof (unsigned int) == sizeof (float)
/// * alignof (unsigned int) == alignof (float)
/// * sizeof (uint16_t) == 2
///
class OPENVDB_API half
{
public:
/// A special tag that lets us initialize a half from the raw bits.
enum OPENVDB_API FromBitsTag
{
FromBits
};
/// @{
/// @name Constructors
/// Default construction provides no initialization (hence it is
/// not constexpr).
half() noexcept = default;
/// Construct from float
half (float f) noexcept;
/// Construct from bit-vector
constexpr half (FromBitsTag, uint16_t bits) noexcept;
/// Copy constructor
constexpr half (const half&) noexcept = default;
/// Move constructor
constexpr half (half&&) noexcept = default;
/// Destructor
~half() noexcept = default;
/// @}
/// Conversion to float
operator float() const noexcept;
/// @{
/// @name Basic Algebra
/// Unary minus
constexpr half operator-() const noexcept;
/// Assignment
half& operator= (const half& h) noexcept = default;
/// Move assignment
half& operator= (half&& h) noexcept = default;
/// Assignment from float
half& operator= (float f) noexcept;
/// Addition assignment
half& operator+= (half h) noexcept;
/// Addition assignment from float
half& operator+= (float f) noexcept;
/// Subtraction assignment
half& operator-= (half h) noexcept;
/// Subtraction assignment from float
half& operator-= (float f) noexcept;
/// Multiplication assignment
half& operator*= (half h) noexcept;
/// Multiplication assignment from float
half& operator*= (float f) noexcept;
/// Division assignment
half& operator/= (half h) noexcept;
/// Division assignment from float
half& operator/= (float f) noexcept;
/// @}
/// Round to n-bit precision (n should be between 0 and 10).
/// After rounding, the significand's 10-n least significant
/// bits will be zero.
constexpr half round (unsigned int n) const noexcept;
/// @{
/// @name Classification
/// Return true if a normalized number, a denormalized number, or
/// zero.
constexpr bool isFinite() const noexcept;
/// Return true if a normalized number.
constexpr bool isNormalized() const noexcept;
/// Return true if a denormalized number.
constexpr bool isDenormalized() const noexcept;
/// Return true if zero.
constexpr bool isZero() const noexcept;
/// Return true if NAN.
constexpr bool isNan() const noexcept;
/// Return true if a positive or a negative infinity
constexpr bool isInfinity() const noexcept;
/// Return true if the sign bit is set (negative)
constexpr bool isNegative() const noexcept;
/// @}
/// @{
/// @name Special values
/// Return +infinity
static constexpr half posInf() noexcept;
/// Return -infinity
static constexpr half negInf() noexcept;
/// Returns a NAN with the bit pattern 0111111111111111
static constexpr half qNan() noexcept;
/// Return a NAN with the bit pattern 0111110111111111
static constexpr half sNan() noexcept;
/// @}
/// @{
/// @name Access to the internal representation
/// Return the bit pattern
constexpr uint16_t bits() const noexcept;
/// Set the bit pattern
constexpr void setBits (uint16_t bits) noexcept;
/// @}
public:
static_assert (sizeof (float) == sizeof (uint32_t),
"Assumption about the size of floats correct");
using uif = imath_half_uif;
private:
constexpr uint16_t mantissa() const noexcept;
constexpr uint16_t exponent() const noexcept;
uint16_t _h;
};
//----------------------------
// Half-from-float constructor
//----------------------------
inline half::half (float f) noexcept
: _h (imath_float_to_half (f))
{
}
//------------------------------------------
// Half from raw bits constructor
//------------------------------------------
inline constexpr half::half (FromBitsTag, uint16_t bits) noexcept : _h (bits)
{}
//-------------------------
// Half-to-float conversion
//-------------------------
inline half::operator float() const noexcept
{
return imath_half_to_float (_h);
}
//-------------------------
// Round to n-bit precision
//-------------------------
inline constexpr half
half::round (unsigned int n) const noexcept
{
//
// Parameter check.
//
if (n >= 10)
return *this;
//
// Disassemble h into the sign, s,
// and the combined exponent and significand, e.
//
uint16_t s = _h & 0x8000;
uint16_t e = _h & 0x7fff;
//
// Round the exponent and significand to the nearest value
// where ones occur only in the (10-n) most significant bits.
// Note that the exponent adjusts automatically if rounding
// up causes the significand to overflow.
//
e >>= 9 - n;
e += e & 1;
e <<= 9 - n;
//
// Check for exponent overflow.
//
if (e >= 0x7c00)
{
//
// Overflow occurred -- truncate instead of rounding.
//
e = _h;
e >>= 10 - n;
e <<= 10 - n;
}
//
// Put the original sign bit back.
//
half h (FromBits, s | e);
return h;
}
//-----------------------
// Other inline functions
//-----------------------
inline constexpr half
half::operator-() const noexcept
{
return half (FromBits, bits() ^ 0x8000);
}
inline half&
half::operator= (float f) noexcept
{
*this = half (f);
return *this;
}
inline half&
half::operator+= (half h) noexcept
{
*this = half (float (*this) + float (h));
return *this;
}
inline half&
half::operator+= (float f) noexcept
{
*this = half (float (*this) + f);
return *this;
}
inline half&
half::operator-= (half h) noexcept
{
*this = half (float (*this) - float (h));
return *this;
}
inline half&
half::operator-= (float f) noexcept
{
*this = half (float (*this) - f);
return *this;
}
inline half&
half::operator*= (half h) noexcept
{
*this = half (float (*this) * float (h));
return *this;
}
inline half&
half::operator*= (float f) noexcept
{
*this = half (float (*this) * f);
return *this;
}
inline half&
half::operator/= (half h) noexcept
{
*this = half (float (*this) / float (h));
return *this;
}
inline half&
half::operator/= (float f) noexcept
{
*this = half (float (*this) / f);
return *this;
}
inline constexpr uint16_t
half::mantissa() const noexcept
{
return _h & 0x3ff;
}
inline constexpr uint16_t
half::exponent() const noexcept
{
return (_h >> 10) & 0x001f;
}
inline constexpr bool
half::isFinite() const noexcept
{
return exponent() < 31;
}
inline constexpr bool
half::isNormalized() const noexcept
{
return exponent() > 0 && exponent() < 31;
}
inline constexpr bool
half::isDenormalized() const noexcept
{
return exponent() == 0 && mantissa() != 0;
}
inline constexpr bool
half::isZero() const noexcept
{
return (_h & 0x7fff) == 0;
}
inline constexpr bool
half::isNan() const noexcept
{
return exponent() == 31 && mantissa() != 0;
}
inline constexpr bool
half::isInfinity() const noexcept
{
return exponent() == 31 && mantissa() == 0;
}
inline constexpr bool
half::isNegative() const noexcept
{
return (_h & 0x8000) != 0;
}
inline constexpr half
half::posInf() noexcept
{
return half (FromBits, 0x7c00);
}
inline constexpr half
half::negInf() noexcept
{
return half (FromBits, 0xfc00);
}
inline constexpr half
half::qNan() noexcept
{
return half (FromBits, 0x7fff);
}
inline constexpr half
half::sNan() noexcept
{
return half (FromBits, 0x7dff);
}
inline constexpr uint16_t
half::bits() const noexcept
{
return _h;
}
inline constexpr void
half::setBits (uint16_t bits) noexcept
{
_h = bits;
}
//----------
// Debugging
//----------
OPENVDB_API void printBits (std::ostream& os, half h);
OPENVDB_API void printBits (std::ostream& os, float f);
OPENVDB_API void printBits (char c[19], half h);
OPENVDB_API void printBits (char c[35], float f);
/// Output h to os, formatted as a float
OPENVDB_API std::ostream& operator<< (std::ostream& os, half h);
/// Input h from is
OPENVDB_API std::istream& operator>> (std::istream& is, half& h);
} // namespace internal
} // namespace math
} // namespace OPENVDB_VERSION_NAME
} // namespace openvdb
#include <limits>
namespace std
{
template <> class numeric_limits<openvdb::math::internal::half>
{
public:
static const bool is_specialized = true;
static constexpr openvdb::math::internal::half min () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x0400); /*VDB_HALF_MIN*/
}
static constexpr openvdb::math::internal::half max () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x7bff); /*HALF_MAX*/
}
static constexpr openvdb::math::internal::half lowest ()
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0xfbff); /* -HALF_MAX */
}
static constexpr int digits = VDB_HALF_MANT_DIG;
static constexpr int digits10 = VDB_HALF_DIG;
static constexpr int max_digits10 = VDB_HALF_DECIMAL_DIG;
static constexpr bool is_signed = true;
static constexpr bool is_integer = false;
static constexpr bool is_exact = false;
static constexpr int radix = VDB_HALF_RADIX;
static constexpr openvdb::math::internal::half epsilon () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x1400); /*HALF_EPSILON*/
}
static constexpr openvdb::math::internal::half round_error () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x3800); /*0.5*/
}
static constexpr int min_exponent = VDBB_HALF_DENORM_MIN_EXP;
static constexpr int min_exponent10 = VDBB_HALF_DENORM_MIN_10_EXP;
static constexpr int max_exponent = VDB_HALF_MAX_EXP;
static constexpr int max_exponent10 = VDB_HALF_MAX_10_EXP;
static constexpr bool has_infinity = true;
static constexpr bool has_quiet_NaN = true;
static constexpr bool has_signaling_NaN = true;
static constexpr float_denorm_style has_denorm = denorm_present;
static constexpr bool has_denorm_loss = false;
static constexpr openvdb::math::internal::half infinity () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x7c00); /*half::posInf()*/
}
static constexpr openvdb::math::internal::half quiet_NaN () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x7fff); /*half::qNan()*/
}
static constexpr openvdb::math::internal::half signaling_NaN () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x7dff); /*half::sNan()*/
}
static constexpr openvdb::math::internal::half denorm_min () noexcept
{
return openvdb::math::internal::half (openvdb::math::internal::half::FromBits, 0x0001); /*VDBB_HALF_DENORM_MIN*/
}
static constexpr bool is_iec559 = false;
static constexpr bool is_bounded = false;
static constexpr bool is_modulo = false;
static constexpr bool traps = true;
static constexpr bool tinyness_before = false;
static constexpr float_round_style round_style = round_to_nearest;
};
} // namespace std
OPENVDB_NO_TYPE_CONVERSION_WARNING_END
#endif // OPENVDB_MATH_HALF_HAS_BEEN_INCLUDED
VDB_HALF_DECIMAL_DIG
#define VDB_HALF_DECIMAL_DIG
imath_half_bits_t
uint16_t imath_half_bits_t
a type for both C-only programs and C++ to use the same utilities
Definition Half.h:279
printBits
OPENVDB_API void printBits(std::ostream &os, half h)
VDB_HALF_MAX_10_EXP
#define VDB_HALF_MAX_10_EXP
Definition Half.h:269
imath_half_uif_t
union imath_half_uif imath_half_uif_t
a type for both C-only programs and C++ to use the same utilities
VDBB_HALF_DENORM_MIN_EXP
#define VDBB_HALF_DENORM_MIN_EXP
VDB_HALF_DIG
#define VDB_HALF_DIG
VDBB_HALF_DENORM_MIN_10_EXP
#define VDBB_HALF_DENORM_MIN_10_EXP
Definition Half.h:266
imath_float_to_half
static imath_half_bits_t imath_float_to_half(float f)
Definition Half.h:382
half
imath_half_bits_t half
if we're in a C-only context, alias the half bits type to half
Definition Half.h:283
VDB_HALF_MAX_EXP
#define VDB_HALF_MAX_EXP
Definition Half.h:263
VDB_HALF_RADIX
#define VDB_HALF_RADIX
operator>>
OPENVDB_API std::istream & operator>>(std::istream &is, half &h)
Input h from is.
VDB_HALF_MANT_DIG
#define VDB_HALF_MANT_DIG
imath_half_to_float
static float imath_half_to_float(imath_half_bits_t h)
Definition Half.h:300
operator<<
OPENVDB_API std::ostream & operator<<(std::ostream &os, half h)
Output h to os, formatted as a float.
Platform.h
OPENVDB_NO_TYPE_CONVERSION_WARNING_BEGIN
#define OPENVDB_NO_TYPE_CONVERSION_WARNING_BEGIN
Bracket code with OPENVDB_NO_TYPE_CONVERSION_WARNING_BEGIN/_END, to inhibit warnings about type conve...
Definition Platform.h:227
OPENVDB_API
#define OPENVDB_API
Definition Platform.h:274
OPENVDB_UNLIKELY
#define OPENVDB_UNLIKELY(x)
Definition Platform.h:92
OPENVDB_NO_TYPE_CONVERSION_WARNING_END
#define OPENVDB_NO_TYPE_CONVERSION_WARNING_END
Definition Platform.h:228
OPENVDB_LIKELY
#define OPENVDB_LIKELY(x)
Definition Platform.h:91
half
Definition Half.h:503
half::posInf
static constexpr half posInf() noexcept
Return +infinity.
Definition Half.h:862
half::isNormalized
constexpr bool isNormalized() const noexcept
Return true if a normalized number.
Definition Half.h:826
half::qNan
static constexpr half qNan() noexcept
Returns a NAN with the bit pattern 0111111111111111.
Definition Half.h:874
half::isFinite
constexpr bool isFinite() const noexcept
Definition Half.h:820
half::isDenormalized
constexpr bool isDenormalized() const noexcept
Return true if a denormalized number.
Definition Half.h:832
half::operator-
constexpr half operator-() const noexcept
Unary minus.
Definition Half.h:739
half::isNegative
constexpr bool isNegative() const noexcept
Return true if the sign bit is set (negative)
Definition Half.h:856
half::isZero
constexpr bool isZero() const noexcept
Return true if zero.
Definition Half.h:838
half::uif
imath_half_uif uif
Definition Half.h:642
half::setBits
constexpr void setBits(uint16_t bits) noexcept
Set the bit pattern.
Definition Half.h:892
half::bits
constexpr uint16_t bits() const noexcept
Return the bit pattern.
Definition Half.h:886
half::isInfinity
constexpr bool isInfinity() const noexcept
Return true if a positive or a negative infinity.
Definition Half.h:850
half::sNan
static constexpr half sNan() noexcept
Return a NAN with the bit pattern 0111110111111111.
Definition Half.h:880
half::negInf
static constexpr half negInf() noexcept
Return -infinity.
Definition Half.h:868
half::isNan
constexpr bool isNan() const noexcept
Return true if NAN.
Definition Half.h:844
half::half
half() noexcept=default
half::round
constexpr half round(unsigned int n) const noexcept
Definition Half.h:682
std::numeric_limits< openvdb::math::internal::half >::max_digits10
static constexpr int max_digits10
Definition Half.h:942
std::numeric_limits< openvdb::math::internal::half >::traps
static constexpr bool traps
Definition Half.h:987
std::numeric_limits< openvdb::math::internal::half >::quiet_NaN
static constexpr openvdb::math::internal::half quiet_NaN() noexcept
Definition Half.h:970
std::numeric_limits< openvdb::math::internal::half >::round_error
static constexpr openvdb::math::internal::half round_error() noexcept
Definition Half.h:951
std::numeric_limits< openvdb::math::internal::half >::radix
static constexpr int radix
Definition Half.h:946
std::numeric_limits< openvdb::math::internal::half >::is_iec559
static constexpr bool is_iec559
Definition Half.h:983
std::numeric_limits< openvdb::math::internal::half >::has_denorm
static constexpr float_denorm_style has_denorm
Definition Half.h:964
std::numeric_limits< openvdb::math::internal::half >::denorm_min
static constexpr openvdb::math::internal::half denorm_min() noexcept
Definition Half.h:978
std::numeric_limits< openvdb::math::internal::half >::infinity
static constexpr openvdb::math::internal::half infinity() noexcept
Definition Half.h:966
std::numeric_limits< openvdb::math::internal::half >::max_exponent
static constexpr int max_exponent
Definition Half.h:958
std::numeric_limits< openvdb::math::internal::half >::digits
static constexpr int digits
Definition Half.h:940
std::numeric_limits< openvdb::math::internal::half >::is_modulo
static constexpr bool is_modulo
Definition Half.h:985
std::numeric_limits< openvdb::math::internal::half >::signaling_NaN
static constexpr openvdb::math::internal::half signaling_NaN() noexcept
Definition Half.h:974
std::numeric_limits< openvdb::math::internal::half >::has_denorm_loss
static constexpr bool has_denorm_loss
Definition Half.h:965
std::numeric_limits< openvdb::math::internal::half >::has_infinity
static constexpr bool has_infinity
Definition Half.h:961
std::numeric_limits< openvdb::math::internal::half >::digits10
static constexpr int digits10
Definition Half.h:941
std::numeric_limits< openvdb::math::internal::half >::max
static constexpr openvdb::math::internal::half max() noexcept
Definition Half.h:931
std::numeric_limits< openvdb::math::internal::half >::min
static constexpr openvdb::math::internal::half min() noexcept
Definition Half.h:927
std::numeric_limits< openvdb::math::internal::half >::max_exponent10
static constexpr int max_exponent10
Definition Half.h:959
std::numeric_limits< openvdb::math::internal::half >::min_exponent
static constexpr int min_exponent
Definition Half.h:956
std::numeric_limits< openvdb::math::internal::half >::lowest
static constexpr openvdb::math::internal::half lowest()
Definition Half.h:935
std::numeric_limits< openvdb::math::internal::half >::is_integer
static constexpr bool is_integer
Definition Half.h:944
std::numeric_limits< openvdb::math::internal::half >::is_exact
static constexpr bool is_exact
Definition Half.h:945
std::numeric_limits< openvdb::math::internal::half >::is_signed
static constexpr bool is_signed
Definition Half.h:943
std::numeric_limits< openvdb::math::internal::half >::is_specialized
static const bool is_specialized
Definition Half.h:925
std::numeric_limits< openvdb::math::internal::half >::is_bounded
static constexpr bool is_bounded
Definition Half.h:984
std::numeric_limits< openvdb::math::internal::half >::min_exponent10
static constexpr int min_exponent10
Definition Half.h:957
std::numeric_limits< openvdb::math::internal::half >::epsilon
static constexpr openvdb::math::internal::half epsilon() noexcept
Definition Half.h:947
std::numeric_limits< openvdb::math::internal::half >::tinyness_before
static constexpr bool tinyness_before
Definition Half.h:988
std::numeric_limits< openvdb::math::internal::half >::has_signaling_NaN
static constexpr bool has_signaling_NaN
Definition Half.h:963
std::numeric_limits< openvdb::math::internal::half >::has_quiet_NaN
static constexpr bool has_quiet_NaN
Definition Half.h:962
std::numeric_limits< openvdb::math::internal::half >::round_style
static constexpr float_round_style round_style
Definition Half.h:989
openvdb
Definition Exceptions.h:13
imath_half_uif
a type for both C-only programs and C++ to use the same utilities
Definition Half.h:273
imath_half_uif::i
uint32_t i
Definition Half.h:274
imath_half_uif::f
float f
Definition Half.h:275
OPENVDB_VERSION_NAME
#define OPENVDB_VERSION_NAME
The version namespace name for this library version.
Definition version.h.in:121
OPENVDB_USE_VERSION_NAMESPACE
#define OPENVDB_USE_VERSION_NAMESPACE
Definition version.h.in:212