Eigen/src/Core/GenericPacketMath.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
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// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_GENERIC_PACKET_MATH_H
#define EIGEN_GENERIC_PACKET_MATH_H

/** \internal
  * \file GenericPacketMath.h
  *
  * Default implementation for types not supported by the vectorization.
  * In practice these functions are provided to make easier the writing
  * of generic vectorized code.
  */

/** \internal \returns a + b (coeff-wise) */
template<typename Packet> inline Packet
ei_padd(const Packet& a,
        const Packet& b) { return a+b; }

/** \internal \returns a - b (coeff-wise) */
template<typename Packet> inline Packet
ei_psub(const Packet& a,
        const Packet& b) { return a-b; }

/** \internal \returns a * b (coeff-wise) */
template<typename Packet> inline Packet
ei_pmul(const Packet& a,
        const Packet& b) { return a*b; }

/** \internal \returns a / b (coeff-wise) */
template<typename Packet> inline Packet
ei_pdiv(const Packet& a,
        const Packet& b) { return a/b; }

/** \internal \returns the min of \a a and \a b  (coeff-wise) */
template<typename Packet> inline Packet
ei_pmin(const Packet& a,
        const Packet& b) { return std::min(a, b); }

/** \internal \returns the max of \a a and \a b  (coeff-wise) */
template<typename Packet> inline Packet
ei_pmax(const Packet& a,
        const Packet& b) { return std::max(a, b); }

/** \internal \returns a packet version of \a *from, from must be 16 bytes aligned */
template<typename Scalar> inline typename ei_packet_traits<Scalar>::type
ei_pload(const Scalar* from) { return *from; }

/** \internal \returns a packet version of \a *from, (un-aligned load) */
template<typename Scalar> inline typename ei_packet_traits<Scalar>::type
ei_ploadu(const Scalar* from) { return *from; }

/** \internal \returns a packet with constant coefficients \a a, e.g.: (a,a,a,a) */
template<typename Scalar> inline typename ei_packet_traits<Scalar>::type
ei_pset1(const Scalar& a) { return a; }

/** \internal copy the packet \a from to \a *to, \a to must be 16 bytes aligned */
template<typename Scalar, typename Packet> inline void ei_pstore(Scalar* to, const Packet& from)
{ (*to) = from; }

/** \internal copy the packet \a from to \a *to, (un-aligned store) */
template<typename Scalar, typename Packet> inline void ei_pstoreu(Scalar* to, const Packet& from)
{ (*to) = from; }

/** \internal \returns the first element of a packet */
template<typename Packet> inline typename ei_unpacket_traits<Packet>::type ei_pfirst(const Packet& a)
{ return a; }

/** \internal \returns a packet where the element i contains the sum of the packet of \a vec[i] */
template<typename Packet> inline Packet
ei_preduxp(const Packet* vecs) { return vecs[0]; }

/** \internal \returns the sum of the elements of \a a*/
template<typename Packet> inline typename ei_unpacket_traits<Packet>::type ei_predux(const Packet& a)
{ return a; }


/***************************************************************************
* The following functions might not have to be overwritten for vectorized types
***************************************************************************/

/** \internal \returns a * b + c (coeff-wise) */
template<typename Packet> inline Packet
ei_pmadd(const Packet&  a,
         const Packet&  b,
         const Packet&  c)
{ return ei_padd(ei_pmul(a, b),c); }

/** \internal \returns a packet version of \a *from.
  * \If LoadMode equals Aligned, \a from must be 16 bytes aligned */
template<typename Scalar, int LoadMode>
inline typename ei_packet_traits<Scalar>::type ei_ploadt(const Scalar* from)
{
  if(LoadMode == Aligned)
    return ei_pload(from);
  else
    return ei_ploadu(from);
}

/** \internal copy the packet \a from to \a *to.
  * If StoreMode equals Aligned, \a to must be 16 bytes aligned */
template<typename Scalar, typename Packet, int LoadMode>
inline void ei_pstoret(Scalar* to, const Packet& from)
{
  if(LoadMode == Aligned)
    ei_pstore(to, from);
  else
    ei_pstoreu(to, from);
}

/** \internal default implementation of ei_palign() allowing partial specialization */
template<int Offset,typename PacketType>
struct ei_palign_impl
{
  // by default data are aligned, so there is nothing to be done :)
  inline static void run(PacketType&, const PacketType&) {}
};

/** \internal update \a first using the concatenation of the \a Offset last elements
  * of \a first and packet_size minus \a Offset first elements of \a second */
template<int Offset,typename PacketType>
inline void ei_palign(PacketType& first, const PacketType& second)
{
  ei_palign_impl<Offset,PacketType>::run(first,second);
}

#endif // EIGEN_GENERIC_PACKET_MATH_H