diff options
author | Rasmus Munk Larsen <rmlarsen@google.com> | 2020-12-03 22:31:44 +0000 |
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committer | Rasmus Munk Larsen <rmlarsen@google.com> | 2020-12-03 22:31:44 +0000 |
commit | 4d91519a9be061da5d300079fca17dd0b9328050 (patch) | |
tree | 5546a7f478049ce24d8f69f20ad018d6a63ec807 /Eigen/src/Core/arch/Default | |
parent | 25d8ae7465e6430bc2dc7f65800332932d3bb774 (diff) |
Add log2() operator to Eigen
Diffstat (limited to 'Eigen/src/Core/arch/Default')
-rw-r--r-- | Eigen/src/Core/arch/Default/BFloat16.h | 3 | ||||
-rw-r--r-- | Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h | 63 | ||||
-rw-r--r-- | Eigen/src/Core/arch/Default/GenericPacketMathFunctionsFwd.h | 12 | ||||
-rw-r--r-- | Eigen/src/Core/arch/Default/Half.h | 4 |
4 files changed, 71 insertions, 11 deletions
diff --git a/Eigen/src/Core/arch/Default/BFloat16.h b/Eigen/src/Core/arch/Default/BFloat16.h index 351f451a3..616dcf667 100644 --- a/Eigen/src/Core/arch/Default/BFloat16.h +++ b/Eigen/src/Core/arch/Default/BFloat16.h @@ -512,6 +512,9 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 log1p(const bfloat16& a) { EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 log10(const bfloat16& a) { return bfloat16(::log10f(float(a))); } +EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 log2(const bfloat16& a) { + return bfloat16(static_cast<float>(M_LOG2E) * ::logf(float(a))); +} EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 sqrt(const bfloat16& a) { return bfloat16(::sqrtf(float(a))); } diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h index 60db2e12f..c6bb89b05 100644 --- a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h +++ b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h @@ -59,16 +59,16 @@ pldexp_double(Packet a, Packet exponent) return pmul(a, preinterpret<Packet>(plogical_shift_left<52>(ei))); } -// Natural logarithm +// Natural or base 2 logarithm. // Computes log(x) as log(2^e * m) = C*e + log(m), where the constant C =log(2) // and m is in the range [sqrt(1/2),sqrt(2)). In this range, the logarithm can // be easily approximated by a polynomial centered on m=1 for stability. // TODO(gonnet): Further reduce the interval allowing for lower-degree // polynomial interpolants -> ... -> profit! -template <typename Packet> +template <typename Packet, bool base2> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED -Packet plog_float(const Packet _x) +Packet plog_impl_float(const Packet _x) { Packet x = _x; @@ -131,8 +131,13 @@ Packet plog_float(const Packet _x) x = padd(x, y); // Add the logarithm of the exponent back to the result of the interpolation. - const Packet cst_ln2 = pset1<Packet>(M_LN2); - x = pmadd(e, cst_ln2, x); + if (base2) { + const Packet cst_log2e = pset1<Packet>(static_cast<float>(M_LOG2E)); + x = pmadd(x, cst_log2e, e); + } else { + const Packet cst_ln2 = pset1<Packet>(static_cast<float>(M_LN2)); + x = pmadd(e, cst_ln2, x); + } Packet invalid_mask = pcmp_lt_or_nan(_x, pzero(_x)); Packet iszero_mask = pcmp_eq(_x,pzero(_x)); @@ -145,8 +150,23 @@ Packet plog_float(const Packet _x) por(pselect(pos_inf_mask,cst_pos_inf,x), invalid_mask)); } +template <typename Packet> +EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS +EIGEN_UNUSED +Packet plog_float(const Packet _x) +{ + return plog_impl_float<Packet, /* base2 */ false>(_x); +} + +template <typename Packet> +EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS +EIGEN_UNUSED +Packet plog2_float(const Packet _x) +{ + return plog_impl_float<Packet, /* base2 */ true>(_x); +} -/* Returns the base e (2.718...) logarithm of x. +/* Returns the base e (2.718...) or base 2 logarithm of x. * The argument is separated into its exponent and fractional parts. * The logarithm of the fraction in the interval [sqrt(1/2), sqrt(2)], * is approximated by @@ -155,16 +175,16 @@ Packet plog_float(const Packet _x) * * for more detail see: http://www.netlib.org/cephes/ */ -template <typename Packet> +template <typename Packet, bool base2> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED -Packet plog_double(const Packet _x) +Packet plog_impl_double(const Packet _x) { Packet x = _x; const Packet cst_1 = pset1<Packet>(1.0); const Packet cst_neg_half = pset1<Packet>(-0.5); - // The smallest non denormalized float number. + // The smallest non denormalized double. const Packet cst_min_norm_pos = pset1frombits<Packet>( static_cast<uint64_t>(0x0010000000000000ull)); const Packet cst_minus_inf = pset1frombits<Packet>( static_cast<uint64_t>(0xfff0000000000000ull)); const Packet cst_pos_inf = pset1frombits<Packet>( static_cast<uint64_t>(0x7ff0000000000000ull)); @@ -232,8 +252,13 @@ Packet plog_double(const Packet _x) x = padd(x, y); // Add the logarithm of the exponent back to the result of the interpolation. - const Packet cst_ln2 = pset1<Packet>(M_LN2); - x = pmadd(e, cst_ln2, x); + if (base2) { + const Packet cst_log2e = pset1<Packet>(M_LOG2E); + x = pmadd(x, cst_log2e, e); + } else { + const Packet cst_ln2 = pset1<Packet>(M_LN2); + x = pmadd(e, cst_ln2, x); + } Packet invalid_mask = pcmp_lt_or_nan(_x, pzero(_x)); Packet iszero_mask = pcmp_eq(_x,pzero(_x)); @@ -246,6 +271,22 @@ Packet plog_double(const Packet _x) por(pselect(pos_inf_mask,cst_pos_inf,x), invalid_mask)); } +template <typename Packet> +EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS +EIGEN_UNUSED +Packet plog_double(const Packet _x) +{ + return plog_impl_double<Packet, /* base2 */ false>(_x); +} + +template <typename Packet> +EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS +EIGEN_UNUSED +Packet plog2_double(const Packet _x) +{ + return plog_impl_double<Packet, /* base2 */ true>(_x); +} + /** \internal \returns log(1 + x) computed using W. Kahan's formula. See: http://www.plunk.org/~hatch/rightway.php */ diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctionsFwd.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctionsFwd.h index 0e02a1b20..b0f0b78fc 100644 --- a/Eigen/src/Core/arch/Default/GenericPacketMathFunctionsFwd.h +++ b/Eigen/src/Core/arch/Default/GenericPacketMathFunctionsFwd.h @@ -32,12 +32,24 @@ EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet plog_float(const Packet _x); +/** \internal \returns log2(x) for single precision float */ +template <typename Packet> +EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS +EIGEN_UNUSED +Packet plog2_float(const Packet _x); + /** \internal \returns log(x) for single precision float */ template <typename Packet> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet plog_double(const Packet _x); +/** \internal \returns log2(x) for single precision float */ +template <typename Packet> +EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS +EIGEN_UNUSED +Packet plog2_double(const Packet _x); + /** \internal \returns log(1 + x) */ template<typename Packet> Packet generic_plog1p(const Packet& x); diff --git a/Eigen/src/Core/arch/Default/Half.h b/Eigen/src/Core/arch/Default/Half.h index 7029c500d..db85f4edf 100644 --- a/Eigen/src/Core/arch/Default/Half.h +++ b/Eigen/src/Core/arch/Default/Half.h @@ -622,6 +622,10 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half log1p(const half& a) { EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half log10(const half& a) { return half(::log10f(float(a))); } +EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half log2(const half& a) { + return half(static_cast<float>(M_LOG2E) * ::logf(float(a))); +} + EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half sqrt(const half& a) { #if (EIGEN_CUDA_SDK_VER >= 80000 && defined EIGEN_CUDA_ARCH && EIGEN_CUDA_ARCH >= 530) || \ defined(EIGEN_HIP_DEVICE_COMPILE) |