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

1 files changed, 3 insertions, 105 deletions

diff --git a/Eigen/src/Core/functors/UnaryFunctors.h b/Eigen/src/Core/functors/UnaryFunctors.h
index e2f3d869f..2a57a5fd9 100644
--- a/Eigen/src/Core/functors/UnaryFunctors.h
+++ b/Eigen/src/Core/functors/UnaryFunctors.h
@@ -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 {