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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud (at) inria.fr>
      5 //
      6 // This Source Code Form is subject to the terms of the Mozilla
      7 // Public License v. 2.0. If a copy of the MPL was not distributed
      8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
      9 
     10 #ifndef EIGEN_SELFADJOINT_MATRIX_VECTOR_H
     11 #define EIGEN_SELFADJOINT_MATRIX_VECTOR_H
     12 
     13 namespace Eigen {
     14 
     15 namespace internal {
     16 
     17 /* Optimized selfadjoint matrix * vector product:
     18  * This algorithm processes 2 columns at onces that allows to both reduce
     19  * the number of load/stores of the result by a factor 2 and to reduce
     20  * the instruction dependency.
     21  */
     22 
     23 template<typename Scalar, typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs, int Version=Specialized>
     24 struct selfadjoint_matrix_vector_product;
     25 
     26 template<typename Scalar, typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs, int Version>
     27 struct selfadjoint_matrix_vector_product
     28 
     29 {
     30 static EIGEN_DONT_INLINE void run(
     31   Index size,
     32   const Scalar*  lhs, Index lhsStride,
     33   const Scalar* _rhs, Index rhsIncr,
     34   Scalar* res,
     35   Scalar alpha);
     36 };
     37 
     38 template<typename Scalar, typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs, int Version>
     39 EIGEN_DONT_INLINE void selfadjoint_matrix_vector_product<Scalar,Index,StorageOrder,UpLo,ConjugateLhs,ConjugateRhs,Version>::run(
     40   Index size,
     41   const Scalar*  lhs, Index lhsStride,
     42   const Scalar* _rhs, Index rhsIncr,
     43   Scalar* res,
     44   Scalar alpha)
     45 {
     46   typedef typename packet_traits<Scalar>::type Packet;
     47   const Index PacketSize = sizeof(Packet)/sizeof(Scalar);
     48 
     49   enum {
     50     IsRowMajor = StorageOrder==RowMajor ? 1 : 0,
     51     IsLower = UpLo == Lower ? 1 : 0,
     52     FirstTriangular = IsRowMajor == IsLower
     53   };
     54 
     55   conj_helper<Scalar,Scalar,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs,  IsRowMajor), ConjugateRhs> cj0;
     56   conj_helper<Scalar,Scalar,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs, !IsRowMajor), ConjugateRhs> cj1;
     57   conj_helper<Scalar,Scalar,NumTraits<Scalar>::IsComplex, ConjugateRhs> cjd;
     58 
     59   conj_helper<Packet,Packet,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs,  IsRowMajor), ConjugateRhs> pcj0;
     60   conj_helper<Packet,Packet,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs, !IsRowMajor), ConjugateRhs> pcj1;
     61 
     62   Scalar cjAlpha = ConjugateRhs ? numext::conj(alpha) : alpha;
     63 
     64   // FIXME this copy is now handled outside product_selfadjoint_vector, so it could probably be removed.
     65   // if the rhs is not sequentially stored in memory we copy it to a temporary buffer,
     66   // this is because we need to extract packets
     67   ei_declare_aligned_stack_constructed_variable(Scalar,rhs,size,rhsIncr==1 ? const_cast<Scalar*>(_rhs) : 0);
     68   if (rhsIncr!=1)
     69   {
     70     const Scalar* it = _rhs;
     71     for (Index i=0; i<size; ++i, it+=rhsIncr)
     72       rhs[i] = *it;
     73   }
     74 
     75   Index bound = (std::max)(Index(0),size-8) & 0xfffffffe;
     76   if (FirstTriangular)
     77     bound = size - bound;
     78 
     79   for (Index j=FirstTriangular ? bound : 0;
     80        j<(FirstTriangular ? size : bound);j+=2)
     81   {
     82     const Scalar* EIGEN_RESTRICT A0 = lhs + j*lhsStride;
     83     const Scalar* EIGEN_RESTRICT A1 = lhs + (j+1)*lhsStride;
     84 
     85     Scalar t0 = cjAlpha * rhs[j];
     86     Packet ptmp0 = pset1<Packet>(t0);
     87     Scalar t1 = cjAlpha * rhs[j+1];
     88     Packet ptmp1 = pset1<Packet>(t1);
     89 
     90     Scalar t2(0);
     91     Packet ptmp2 = pset1<Packet>(t2);
     92     Scalar t3(0);
     93     Packet ptmp3 = pset1<Packet>(t3);
     94 
     95     size_t starti = FirstTriangular ? 0 : j+2;
     96     size_t endi   = FirstTriangular ? j : size;
     97     size_t alignedStart = (starti) + internal::first_aligned(&res[starti], endi-starti);
     98     size_t alignedEnd = alignedStart + ((endi-alignedStart)/(PacketSize))*(PacketSize);
     99 
    100     // TODO make sure this product is a real * complex and that the rhs is properly conjugated if needed
    101     res[j]   += cjd.pmul(numext::real(A0[j]), t0);
    102     res[j+1] += cjd.pmul(numext::real(A1[j+1]), t1);
    103     if(FirstTriangular)
    104     {
    105       res[j]   += cj0.pmul(A1[j],   t1);
    106       t3       += cj1.pmul(A1[j],   rhs[j]);
    107     }
    108     else
    109     {
    110       res[j+1] += cj0.pmul(A0[j+1],t0);
    111       t2 += cj1.pmul(A0[j+1], rhs[j+1]);
    112     }
    113 
    114     for (size_t i=starti; i<alignedStart; ++i)
    115     {
    116       res[i] += t0 * A0[i] + t1 * A1[i];
    117       t2 += numext::conj(A0[i]) * rhs[i];
    118       t3 += numext::conj(A1[i]) * rhs[i];
    119     }
    120     // Yes this an optimization for gcc 4.3 and 4.4 (=> huge speed up)
    121     // gcc 4.2 does this optimization automatically.
    122     const Scalar* EIGEN_RESTRICT a0It  = A0  + alignedStart;
    123     const Scalar* EIGEN_RESTRICT a1It  = A1  + alignedStart;
    124     const Scalar* EIGEN_RESTRICT rhsIt = rhs + alignedStart;
    125           Scalar* EIGEN_RESTRICT resIt = res + alignedStart;
    126     for (size_t i=alignedStart; i<alignedEnd; i+=PacketSize)
    127     {
    128       Packet A0i = ploadu<Packet>(a0It);  a0It  += PacketSize;
    129       Packet A1i = ploadu<Packet>(a1It);  a1It  += PacketSize;
    130       Packet Bi  = ploadu<Packet>(rhsIt); rhsIt += PacketSize; // FIXME should be aligned in most cases
    131       Packet Xi  = pload <Packet>(resIt);
    132 
    133       Xi    = pcj0.pmadd(A0i,ptmp0, pcj0.pmadd(A1i,ptmp1,Xi));
    134       ptmp2 = pcj1.pmadd(A0i,  Bi, ptmp2);
    135       ptmp3 = pcj1.pmadd(A1i,  Bi, ptmp3);
    136       pstore(resIt,Xi); resIt += PacketSize;
    137     }
    138     for (size_t i=alignedEnd; i<endi; i++)
    139     {
    140       res[i] += cj0.pmul(A0[i], t0) + cj0.pmul(A1[i],t1);
    141       t2 += cj1.pmul(A0[i], rhs[i]);
    142       t3 += cj1.pmul(A1[i], rhs[i]);
    143     }
    144 
    145     res[j]   += alpha * (t2 + predux(ptmp2));
    146     res[j+1] += alpha * (t3 + predux(ptmp3));
    147   }
    148   for (Index j=FirstTriangular ? 0 : bound;j<(FirstTriangular ? bound : size);j++)
    149   {
    150     const Scalar* EIGEN_RESTRICT A0 = lhs + j*lhsStride;
    151 
    152     Scalar t1 = cjAlpha * rhs[j];
    153     Scalar t2(0);
    154     // TODO make sure this product is a real * complex and that the rhs is properly conjugated if needed
    155     res[j] += cjd.pmul(numext::real(A0[j]), t1);
    156     for (Index i=FirstTriangular ? 0 : j+1; i<(FirstTriangular ? j : size); i++)
    157     {
    158       res[i] += cj0.pmul(A0[i], t1);
    159       t2 += cj1.pmul(A0[i], rhs[i]);
    160     }
    161     res[j] += alpha * t2;
    162   }
    163 }
    164 
    165 } // end namespace internal
    166 
    167 /***************************************************************************
    168 * Wrapper to product_selfadjoint_vector
    169 ***************************************************************************/
    170 
    171 namespace internal {
    172 template<typename Lhs, int LhsMode, typename Rhs>
    173 struct traits<SelfadjointProductMatrix<Lhs,LhsMode,false,Rhs,0,true> >
    174   : traits<ProductBase<SelfadjointProductMatrix<Lhs,LhsMode,false,Rhs,0,true>, Lhs, Rhs> >
    175 {};
    176 }
    177 
    178 template<typename Lhs, int LhsMode, typename Rhs>
    179 struct SelfadjointProductMatrix<Lhs,LhsMode,false,Rhs,0,true>
    180   : public ProductBase<SelfadjointProductMatrix<Lhs,LhsMode,false,Rhs,0,true>, Lhs, Rhs >
    181 {
    182   EIGEN_PRODUCT_PUBLIC_INTERFACE(SelfadjointProductMatrix)
    183 
    184   enum {
    185     LhsUpLo = LhsMode&(Upper|Lower)
    186   };
    187 
    188   SelfadjointProductMatrix(const Lhs& lhs, const Rhs& rhs) : Base(lhs,rhs) {}
    189 
    190   template<typename Dest> void scaleAndAddTo(Dest& dest, const Scalar& alpha) const
    191   {
    192     typedef typename Dest::Scalar ResScalar;
    193     typedef typename Base::RhsScalar RhsScalar;
    194     typedef Map<Matrix<ResScalar,Dynamic,1>, Aligned> MappedDest;
    195 
    196     eigen_assert(dest.rows()==m_lhs.rows() && dest.cols()==m_rhs.cols());
    197 
    198     typename internal::add_const_on_value_type<ActualLhsType>::type lhs = LhsBlasTraits::extract(m_lhs);
    199     typename internal::add_const_on_value_type<ActualRhsType>::type rhs = RhsBlasTraits::extract(m_rhs);
    200 
    201     Scalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(m_lhs)
    202                                * RhsBlasTraits::extractScalarFactor(m_rhs);
    203 
    204     enum {
    205       EvalToDest = (Dest::InnerStrideAtCompileTime==1),
    206       UseRhs = (_ActualRhsType::InnerStrideAtCompileTime==1)
    207     };
    208 
    209     internal::gemv_static_vector_if<ResScalar,Dest::SizeAtCompileTime,Dest::MaxSizeAtCompileTime,!EvalToDest> static_dest;
    210     internal::gemv_static_vector_if<RhsScalar,_ActualRhsType::SizeAtCompileTime,_ActualRhsType::MaxSizeAtCompileTime,!UseRhs> static_rhs;
    211 
    212     ei_declare_aligned_stack_constructed_variable(ResScalar,actualDestPtr,dest.size(),
    213                                                   EvalToDest ? dest.data() : static_dest.data());
    214 
    215     ei_declare_aligned_stack_constructed_variable(RhsScalar,actualRhsPtr,rhs.size(),
    216         UseRhs ? const_cast<RhsScalar*>(rhs.data()) : static_rhs.data());
    217 
    218     if(!EvalToDest)
    219     {
    220       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    221       int size = dest.size();
    222       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    223       #endif
    224       MappedDest(actualDestPtr, dest.size()) = dest;
    225     }
    226 
    227     if(!UseRhs)
    228     {
    229       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    230       int size = rhs.size();
    231       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    232       #endif
    233       Map<typename _ActualRhsType::PlainObject>(actualRhsPtr, rhs.size()) = rhs;
    234     }
    235 
    236 
    237     internal::selfadjoint_matrix_vector_product<Scalar, Index, (internal::traits<_ActualLhsType>::Flags&RowMajorBit) ? RowMajor : ColMajor, int(LhsUpLo), bool(LhsBlasTraits::NeedToConjugate), bool(RhsBlasTraits::NeedToConjugate)>::run
    238       (
    239         lhs.rows(),                             // size
    240         &lhs.coeffRef(0,0),  lhs.outerStride(), // lhs info
    241         actualRhsPtr, 1,                        // rhs info
    242         actualDestPtr,                          // result info
    243         actualAlpha                             // scale factor
    244       );
    245 
    246     if(!EvalToDest)
    247       dest = MappedDest(actualDestPtr, dest.size());
    248   }
    249 };
    250 
    251 namespace internal {
    252 template<typename Lhs, typename Rhs, int RhsMode>
    253 struct traits<SelfadjointProductMatrix<Lhs,0,true,Rhs,RhsMode,false> >
    254   : traits<ProductBase<SelfadjointProductMatrix<Lhs,0,true,Rhs,RhsMode,false>, Lhs, Rhs> >
    255 {};
    256 }
    257 
    258 template<typename Lhs, typename Rhs, int RhsMode>
    259 struct SelfadjointProductMatrix<Lhs,0,true,Rhs,RhsMode,false>
    260   : public ProductBase<SelfadjointProductMatrix<Lhs,0,true,Rhs,RhsMode,false>, Lhs, Rhs >
    261 {
    262   EIGEN_PRODUCT_PUBLIC_INTERFACE(SelfadjointProductMatrix)
    263 
    264   enum {
    265     RhsUpLo = RhsMode&(Upper|Lower)
    266   };
    267 
    268   SelfadjointProductMatrix(const Lhs& lhs, const Rhs& rhs) : Base(lhs,rhs) {}
    269 
    270   template<typename Dest> void scaleAndAddTo(Dest& dest, const Scalar& alpha) const
    271   {
    272     // let's simply transpose the product
    273     Transpose<Dest> destT(dest);
    274     SelfadjointProductMatrix<Transpose<const Rhs>, int(RhsUpLo)==Upper ? Lower : Upper, false,
    275                              Transpose<const Lhs>, 0, true>(m_rhs.transpose(), m_lhs.transpose()).scaleAndAddTo(destT, alpha);
    276   }
    277 };
    278 
    279 } // end namespace Eigen
    280 
    281 #endif // EIGEN_SELFADJOINT_MATRIX_VECTOR_H
    282