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Factorize the 4 copies of tanh implementations, make numext::tanh consistent with array::tanh, enable fast tanh in fast-math mode only.

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This commit is contained in:
Gael Guennebaud 2016-08-23 14:23:08 +02:00
parent 82147cefff
commit a4c266f827
6 changed files with 89 additions and 193 deletions
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1
Eigen/Core
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@ -329,6 +329,7 @@ using std::ptrdiff_t;
#include "src/Core/NumTraits.h"
#include "src/Core/MathFunctions.h"
#include "src/Core/GenericPacketMath.h"
#include "src/Core/MathFunctionsImpl.h"
#if defined EIGEN_VECTORIZE_AVX
// Use AVX for floats and doubles, SSE for integers

7
Eigen/src/Core/MathFunctions.h
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@ -787,6 +787,8 @@ template<typename T> EIGEN_DEVICE_FUNC bool isfinite_impl(const std::complex<T>&
template<typename T> EIGEN_DEVICE_FUNC bool isnan_impl(const std::complex<T>& x);
template<typename T> EIGEN_DEVICE_FUNC bool isinf_impl(const std::complex<T>& x);
template<typename T> T generic_fast_tanh_float(const T& a_x);
} // end namespace internal
/****************************************************************************
@ -1178,6 +1180,11 @@ T tanh(const T &x) {
return tanh(x);
}
#if (!defined(__CUDACC__)) && EIGEN_FAST_MATH
EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE
float tanh(float x) { return internal::generic_fast_tanh_float(x); }
#endif
#ifdef __CUDACC__
template<> EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE
float tanh(const float &x) { return ::tanhf(x); }

74
Eigen/src/Core/MathFunctionsImpl.h Normal file
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@ -0,0 +1,74 @@
// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2014 Pedro Gonnet (pedro.gonnet@gmail.com)
// Copyright (C) 2016 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_MATHFUNCTIONSIMPL_H
#define EIGEN_MATHFUNCTIONSIMPL_H
namespace Eigen {
namespace internal {
/** \internal \returns the hyperbolic tan of \a a (coeff-wise)
Doesn't do anything fancy, just a 13/6-degree rational interpolant which
is accurate up to a couple of ulp in the range [-9, 9], outside of which
the tanh(x) = +/-1.
This implementation works on both scalars and packets.
*/
template<typename T>
EIGEN_DONT_INLINE T generic_fast_tanh_float(const T& a_x)
{
// Clamp the inputs to the range [-9, 9] since anything outside
// this range is +/-1.0f in single-precision.
const T plus_9 = pset1<T>(9.f);
const T minus_9 = pset1<T>(-9.f);
const T x = pmax(minus_9, pmin(plus_9, a_x));
// The monomial coefficients of the numerator polynomial (odd).
const T alpha_1 = pset1<T>(4.89352455891786e-03);
const T alpha_3 = pset1<T>(6.37261928875436e-04);
const T alpha_5 = pset1<T>(1.48572235717979e-05);
const T alpha_7 = pset1<T>(5.12229709037114e-08);
const T alpha_9 = pset1<T>(-8.60467152213735e-11);
const T alpha_11 = pset1<T>(2.00018790482477e-13);
const T alpha_13 = pset1<T>(-2.76076847742355e-16);
// The monomial coefficients of the denominator polynomial (even).
const T beta_0 = pset1<T>(4.89352518554385e-03);
const T beta_2 = pset1<T>(2.26843463243900e-03);
const T beta_4 = pset1<T>(1.18534705686654e-04);
const T beta_6 = pset1<T>(1.19825839466702e-06);
// Since the polynomials are odd/even, we need x^2.
const T x2 = pmul(x, x);
// Evaluate the numerator polynomial p.
T p = pmadd(x2, alpha_13, alpha_11);
p = pmadd(x2, p, alpha_9);
p = pmadd(x2, p, alpha_7);
p = pmadd(x2, p, alpha_5);
p = pmadd(x2, p, alpha_3);
p = pmadd(x2, p, alpha_1);
p = pmul(x, p);
// Evaluate the denominator polynomial p.
T q = pmadd(x2, beta_6, beta_4);
q = pmadd(x2, q, beta_2);
q = pmadd(x2, q, beta_0);
// Divide the numerator by the denominator.
return pdiv(p, q);
}
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_MATHFUNCTIONSIMPL_H

46
Eigen/src/Core/arch/AVX/MathFunctions.h
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@ -266,52 +266,10 @@ pexp<Packet8f>(const Packet8f& _x) {
}
// Hyperbolic Tangent function.
// Doesn't do anything fancy, just a 13/6-degree rational interpolant which
// is accurate up to a couple of ulp in the range [-9, 9], outside of which the
// fl(tanh(x)) = +/-1.
template <>
EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet8f
ptanh<Packet8f>(const Packet8f& _x) {
// Clamp the inputs to the range [-9, 9] since anything outside
// this range is +/-1.0f in single-precision.
_EIGEN_DECLARE_CONST_Packet8f(plus_9, 9.0f);
_EIGEN_DECLARE_CONST_Packet8f(minus_9, -9.0f);
const Packet8f x = pmax(p8f_minus_9, pmin(p8f_plus_9, _x));
// The monomial coefficients of the numerator polynomial (odd).
_EIGEN_DECLARE_CONST_Packet8f(alpha_1, 4.89352455891786e-03f);
_EIGEN_DECLARE_CONST_Packet8f(alpha_3, 6.37261928875436e-04f);
_EIGEN_DECLARE_CONST_Packet8f(alpha_5, 1.48572235717979e-05f);
_EIGEN_DECLARE_CONST_Packet8f(alpha_7, 5.12229709037114e-08f);
_EIGEN_DECLARE_CONST_Packet8f(alpha_9, -8.60467152213735e-11f);
_EIGEN_DECLARE_CONST_Packet8f(alpha_11, 2.00018790482477e-13f);
_EIGEN_DECLARE_CONST_Packet8f(alpha_13, -2.76076847742355e-16f);
// The monomial coefficients of the denominator polynomial (even).
_EIGEN_DECLARE_CONST_Packet8f(beta_0, 4.89352518554385e-03f);
_EIGEN_DECLARE_CONST_Packet8f(beta_2, 2.26843463243900e-03f);
_EIGEN_DECLARE_CONST_Packet8f(beta_4, 1.18534705686654e-04f);
_EIGEN_DECLARE_CONST_Packet8f(beta_6, 1.19825839466702e-06f);
// Since the polynomials are odd/even, we need x^2.
const Packet8f x2 = pmul(x, x);
// Evaluate the numerator polynomial p.
Packet8f p = pmadd(x2, p8f_alpha_13, p8f_alpha_11);
p = pmadd(x2, p, p8f_alpha_9);
p = pmadd(x2, p, p8f_alpha_7);
p = pmadd(x2, p, p8f_alpha_5);
p = pmadd(x2, p, p8f_alpha_3);
p = pmadd(x2, p, p8f_alpha_1);
p = pmul(x, p);
// Evaluate the denominator polynomial p.
Packet8f q = pmadd(x2, p8f_beta_6, p8f_beta_4);
q = pmadd(x2, q, p8f_beta_2);
q = pmadd(x2, q, p8f_beta_0);
// Divide the numerator by the denominator.
return pdiv(p, q);
ptanh<Packet8f>(const Packet8f& x) {
return internal::generic_fast_tanh_float(x);
}
template <>

46
Eigen/src/Core/arch/SSE/MathFunctions.h
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@ -517,52 +517,10 @@ Packet2d prsqrt<Packet2d>(const Packet2d& x) {
}
// Hyperbolic Tangent function.
// Doesn't do anything fancy, just a 13/6-degree rational interpolant which
// is accurate up to a couple of ulp in the range [-9, 9], outside of which the
// fl(tanh(x)) = +/-1.
template <>
EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet4f
ptanh<Packet4f>(const Packet4f& _x) {
// Clamp the inputs to the range [-9, 9] since anything outside
// this range is +/-1.0f in single-precision.
_EIGEN_DECLARE_CONST_Packet4f(plus_9, 9.0f);
_EIGEN_DECLARE_CONST_Packet4f(minus_9, -9.0f);
const Packet4f x = pmax(p4f_minus_9, pmin(p4f_plus_9, _x));
// The monomial coefficients of the numerator polynomial (odd).
_EIGEN_DECLARE_CONST_Packet4f(alpha_1, 4.89352455891786e-03f);
_EIGEN_DECLARE_CONST_Packet4f(alpha_3, 6.37261928875436e-04f);
_EIGEN_DECLARE_CONST_Packet4f(alpha_5, 1.48572235717979e-05f);
_EIGEN_DECLARE_CONST_Packet4f(alpha_7, 5.12229709037114e-08f);
_EIGEN_DECLARE_CONST_Packet4f(alpha_9, -8.60467152213735e-11f);
_EIGEN_DECLARE_CONST_Packet4f(alpha_11, 2.00018790482477e-13f);
_EIGEN_DECLARE_CONST_Packet4f(alpha_13, -2.76076847742355e-16f);
// The monomial coefficients of the denominator polynomial (even).
_EIGEN_DECLARE_CONST_Packet4f(beta_0, 4.89352518554385e-03f);
_EIGEN_DECLARE_CONST_Packet4f(beta_2, 2.26843463243900e-03f);
_EIGEN_DECLARE_CONST_Packet4f(beta_4, 1.18534705686654e-04f);
_EIGEN_DECLARE_CONST_Packet4f(beta_6, 1.19825839466702e-06f);
// Since the polynomials are odd/even, we need x^2.
const Packet4f x2 = pmul(x, x);
// Evaluate the numerator polynomial p.
Packet4f p = pmadd(x2, p4f_alpha_13, p4f_alpha_11);
p = pmadd(x2, p, p4f_alpha_9);
p = pmadd(x2, p, p4f_alpha_7);
p = pmadd(x2, p, p4f_alpha_5);
p = pmadd(x2, p, p4f_alpha_3);
p = pmadd(x2, p, p4f_alpha_1);
p = pmul(x, p);
// Evaluate the denominator polynomial p.
Packet4f q = pmadd(x2, p4f_beta_6, p4f_beta_4);
q = pmadd(x2, q, p4f_beta_2);
q = pmadd(x2, q, p4f_beta_0);
// Divide the numerator by the denominator.
return pdiv(p, q);
ptanh<Packet4f>(const Packet4f& x) {
return internal::generic_fast_tanh_float(x);
}
} // end namespace internal

108
Eigen/src/Core/functors/UnaryFunctors.h
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@ -498,113 +498,11 @@ struct functor_traits<scalar_atan_op<Scalar> >
template <typename Scalar>
struct scalar_tanh_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_tanh_op)
EIGEN_DEVICE_FUNC inline const Scalar operator()(const Scalar& a) const {
/** \internal \returns the hyperbolic tan of \a a (coeff-wise)
Doesn't do anything fancy, just a 13/6-degree rational interpolant
which
is accurate up to a couple of ulp in the range [-9, 9], outside of
which
the fl(tanh(x)) = +/-1. */
// Clamp the inputs to the range [-9, 9] since anything outside
// this range is +/-1.0f in single-precision.
const Scalar plus_9 = static_cast<Scalar>(9.0);
const Scalar minus_9 = static_cast<Scalar>(-9.0);
const Scalar x = numext::maxi(minus_9, numext::mini(plus_9, a));
// Scalarhe monomial coefficients of the numerator polynomial (odd).
const Scalar alpha_1 = static_cast<Scalar>(4.89352455891786e-03);
const Scalar alpha_3 = static_cast<Scalar>(6.37261928875436e-04);
const Scalar alpha_5 = static_cast<Scalar>(1.48572235717979e-05);
const Scalar alpha_7 = static_cast<Scalar>(5.12229709037114e-08);
const Scalar alpha_9 = static_cast<Scalar>(-8.60467152213735e-11);
const Scalar alpha_11 = static_cast<Scalar>(2.00018790482477e-13);
const Scalar alpha_13 = static_cast<Scalar>(-2.76076847742355e-16);
// Scalarhe monomial coefficients of the denominator polynomial (even).
const Scalar beta_0 = static_cast<Scalar>(4.89352518554385e-03);
const Scalar beta_2 = static_cast<Scalar>(2.26843463243900e-03);
const Scalar beta_4 = static_cast<Scalar>(1.18534705686654e-04);
const Scalar beta_6 = static_cast<Scalar>(1.19825839466702e-06);
// Since the polynomials are odd/even, we need x^2.
const Scalar x2 = x * x;
// Evaluate the numerator polynomial p.
Scalar p = x2 * alpha_13 + alpha_11;
p = x2 * p + alpha_9;
p = x2 * p + alpha_7;
p = x2 * p + alpha_5;
p = x2 * p + alpha_3;
p = x2 * p + alpha_1;
p = x * p;
// Evaluate the denominator polynomial p.
Scalar q = x2 * beta_6 + beta_4;
q = x2 * q + beta_2;
q = x2 * q + beta_0;
// Divide the numerator by the denominator.
return p / q;
}
EIGEN_DEVICE_FUNC inline const Scalar operator()(const Scalar& a) const { return numext::tanh(a); }
template <typename Packet>
EIGEN_DEVICE_FUNC inline Packet packetOp(const Packet& _x) const {
/** \internal \returns the hyperbolic tan of \a a (coeff-wise)
Doesn't do anything fancy, just a 13/6-degree rational interpolant which
is accurate up to a couple of ulp in the range [-9, 9], outside of which
the
fl(tanh(x)) = +/-1. */
// Clamp the inputs to the range [-9, 9] since anything outside
// this range is +/-1.0f in single-precision.
const Packet plus_9 = pset1<Packet>(9.0);
const Packet minus_9 = pset1<Packet>(-9.0);
const Packet x = pmax(minus_9, pmin(plus_9, _x));
// The monomial coefficients of the numerator polynomial (odd).
const Packet alpha_1 = pset1<Packet>(4.89352455891786e-03);
const Packet alpha_3 = pset1<Packet>(6.37261928875436e-04);
const Packet alpha_5 = pset1<Packet>(1.48572235717979e-05);
const Packet alpha_7 = pset1<Packet>(5.12229709037114e-08);
const Packet alpha_9 = pset1<Packet>(-8.60467152213735e-11);
const Packet alpha_11 = pset1<Packet>(2.00018790482477e-13);
const Packet alpha_13 = pset1<Packet>(-2.76076847742355e-16);
// The monomial coefficients of the denominator polynomial (even).
const Packet beta_0 = pset1<Packet>(4.89352518554385e-03);
const Packet beta_2 = pset1<Packet>(2.26843463243900e-03);
const Packet beta_4 = pset1<Packet>(1.18534705686654e-04);
const Packet beta_6 = pset1<Packet>(1.19825839466702e-06);
// Since the polynomials are odd/even, we need x^2.
const Packet x2 = pmul(x, x);
// Evaluate the numerator polynomial p.
Packet p = pmadd(x2, alpha_13, alpha_11);
p = pmadd(x2, p, alpha_9);
p = pmadd(x2, p, alpha_7);
p = pmadd(x2, p, alpha_5);
p = pmadd(x2, p, alpha_3);
p = pmadd(x2, p, alpha_1);
p = pmul(x, p);
// Evaluate the denominator polynomial p.
Packet q = pmadd(x2, beta_6, beta_4);
q = pmadd(x2, q, beta_2);
q = pmadd(x2, q, beta_0);
// Divide the numerator by the denominator.
return pdiv(p, q);
}
};
template <>
struct scalar_tanh_op<std::complex<double> > {
EIGEN_DEVICE_FUNC inline const std::complex<double> operator()(
const std::complex<double>& a) const {
return numext::tanh(a);
}
};
template <>
struct scalar_tanh_op<std::complex<float> > {
EIGEN_DEVICE_FUNC inline const std::complex<float> operator()(
const std::complex<float>& a) const {
return numext::tanh(a);
}
EIGEN_DEVICE_FUNC inline Packet packetOp(const Packet& x) const { return ptanh(x); }
};
template <typename Scalar>
struct functor_traits<scalar_tanh_op<Scalar> > {
enum {