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Added support for fast reciprocal square root computation.

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This commit is contained in:
Benoit Steiner
2015-02-26 09:42:41 -08:00
parent 8e817b65d0
commit f41b1f1666
8 changed files with 72 additions and 6 deletions
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19
Eigen/src/Core/functors/UnaryFunctors.h
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@@ -224,6 +224,25 @@ struct functor_traits<scalar_sqrt_op<Scalar> >
};
};
/** \internal
* \brief Template functor to compute the reciprocal square root of a scalar
* \sa class CwiseUnaryOp, Cwise::rsqrt()
*/
template<typename Scalar> struct scalar_rsqrt_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_rsqrt_op)
EIGEN_DEVICE_FUNC inline const Scalar operator() (const Scalar& a) const { using std::sqrt; return Scalar(1)/sqrt(a); }
typedef typename packet_traits<Scalar>::type Packet;
inline Packet packetOp(const Packet& a) const { return internal::prsqrt(a); }
};
template<typename Scalar>
struct functor_traits<scalar_rsqrt_op<Scalar> >
{ enum {
Cost = 5 * NumTraits<Scalar>::MulCost,
PacketAccess = packet_traits<Scalar>::HasRsqrt
};
};
/** \internal
* \brief Template functor to compute the cosine of a scalar
* \sa class CwiseUnaryOp, ArrayBase::cos()