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Add generic PacketMath implementation of the Error Function (erf).

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This commit is contained in:
Rasmus Munk Larsen
2019-09-19 12:48:30 -07:00
parent e02d429637
commit 6de5ed08d8
20 changed files with 265 additions and 90 deletions
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40
unsupported/Eigen/src/SpecialFunctions/SpecialFunctionsFunctors.h
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@@ -238,25 +238,39 @@ struct functor_traits<scalar_polygamma_op<Scalar> >
};
/** \internal
* \brief Template functor to compute the Gauss error function of a
* scalar
* \sa class CwiseUnaryOp, Cwise::erf()
* \brief Template functor to compute the error function of a scalar
* \sa class CwiseUnaryOp, ArrayBase::erf()
*/
template<typename Scalar> struct scalar_erf_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_erf_op)
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const {
using numext::erf; return erf(a);
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar
operator()(const Scalar& a) const {
return numext::erf(a);
}
template <typename Packet>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Packet packetOp(const Packet& x) const {
return perf(x);
}
typedef typename packet_traits<Scalar>::type Packet;
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Packet packetOp(const Packet& a) const { return internal::perf(a); }
};
template<typename Scalar>
struct functor_traits<scalar_erf_op<Scalar> >
{
template <typename Scalar>
struct functor_traits<scalar_erf_op<Scalar> > {
enum {
// Guesstimate
Cost = 10 * NumTraits<Scalar>::MulCost + 5 * NumTraits<Scalar>::AddCost,
PacketAccess = packet_traits<Scalar>::HasErf
PacketAccess = packet_traits<Scalar>::HasErf,
Cost =
(PacketAccess
#ifdef EIGEN_VECTORIZE_FMA
// Haswell can issue 2 add/mul/madd per cycle.
// 10 pmadd, 2 pmul, 1 div, 2 other
? (2 * NumTraits<Scalar>::AddCost +
7 * NumTraits<Scalar>::MulCost +
scalar_div_cost<Scalar, packet_traits<Scalar>::HasDiv>::value)
#else
? (12 * NumTraits<Scalar>::AddCost +
12 * NumTraits<Scalar>::MulCost +
scalar_div_cost<Scalar, packet_traits<Scalar>::HasDiv>::value)
#endif
// Assume for simplicity that this is as expensive as an exp().
: (functor_traits<scalar_exp_op<Scalar> >::Cost))
};
};