diff options
author | Rasmus Munk Larsen <rmlarsen@google.com> | 2020-12-03 14:32:45 -0800 |
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committer | Rasmus Munk Larsen <rmlarsen@google.com> | 2020-12-03 14:32:45 -0800 |
commit | f23dc5b971d1c11bc0fcb7068788a30e4bd7cbf1 (patch) | |
tree | daf4488df55322bc0840f2c75cb38f3884c4141c /Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h | |
parent | 4d91519a9be061da5d300079fca17dd0b9328050 (diff) |
Revert "Add log2() operator to Eigen"
This reverts commit 4d91519a9be061da5d300079fca17dd0b9328050.
Diffstat (limited to 'Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h')
-rw-r--r-- | Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h | 63 |
1 files changed, 11 insertions, 52 deletions
diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h index c6bb89b05..60db2e12f 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 or base 2 logarithm. +// Natural 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, bool base2> +template <typename Packet> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED -Packet plog_impl_float(const Packet _x) +Packet plog_float(const Packet _x) { Packet x = _x; @@ -131,13 +131,8 @@ Packet plog_impl_float(const Packet _x) x = padd(x, y); // Add the logarithm of the exponent back to the result of the interpolation. - 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); - } + 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)); @@ -150,23 +145,8 @@ Packet plog_impl_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...) or base 2 logarithm of x. +/* Returns the base e (2.718...) 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 @@ -175,16 +155,16 @@ Packet plog2_float(const Packet _x) * * for more detail see: http://www.netlib.org/cephes/ */ -template <typename Packet, bool base2> +template <typename Packet> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED -Packet plog_impl_double(const Packet _x) +Packet plog_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 double. + // The smallest non denormalized float number. 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)); @@ -252,13 +232,8 @@ Packet plog_impl_double(const Packet _x) x = padd(x, y); // Add the logarithm of the exponent back to the result of the interpolation. - 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); - } + 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)); @@ -271,22 +246,6 @@ Packet plog_impl_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 */ |