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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_GENERAL_MATRIX_MATRIX_H
     11 #define EIGEN_GENERAL_MATRIX_MATRIX_H
     12 
     13 namespace Eigen {
     14 
     15 namespace internal {
     16 
     17 template<typename _LhsScalar, typename _RhsScalar> class level3_blocking;
     18 
     19 /* Specialization for a row-major destination matrix => simple transposition of the product */
     20 template<
     21   typename Index,
     22   typename LhsScalar, int LhsStorageOrder, bool ConjugateLhs,
     23   typename RhsScalar, int RhsStorageOrder, bool ConjugateRhs>
     24 struct general_matrix_matrix_product<Index,LhsScalar,LhsStorageOrder,ConjugateLhs,RhsScalar,RhsStorageOrder,ConjugateRhs,RowMajor>
     25 {
     26   typedef typename scalar_product_traits<LhsScalar, RhsScalar>::ReturnType ResScalar;
     27   static EIGEN_STRONG_INLINE void run(
     28     Index rows, Index cols, Index depth,
     29     const LhsScalar* lhs, Index lhsStride,
     30     const RhsScalar* rhs, Index rhsStride,
     31     ResScalar* res, Index resStride,
     32     ResScalar alpha,
     33     level3_blocking<RhsScalar,LhsScalar>& blocking,
     34     GemmParallelInfo<Index>* info = 0)
     35   {
     36     // transpose the product such that the result is column major
     37     general_matrix_matrix_product<Index,
     38       RhsScalar, RhsStorageOrder==RowMajor ? ColMajor : RowMajor, ConjugateRhs,
     39       LhsScalar, LhsStorageOrder==RowMajor ? ColMajor : RowMajor, ConjugateLhs,
     40       ColMajor>
     41     ::run(cols,rows,depth,rhs,rhsStride,lhs,lhsStride,res,resStride,alpha,blocking,info);
     42   }
     43 };
     44 
     45 /*  Specialization for a col-major destination matrix
     46  *    => Blocking algorithm following Goto's paper */
     47 template<
     48   typename Index,
     49   typename LhsScalar, int LhsStorageOrder, bool ConjugateLhs,
     50   typename RhsScalar, int RhsStorageOrder, bool ConjugateRhs>
     51 struct general_matrix_matrix_product<Index,LhsScalar,LhsStorageOrder,ConjugateLhs,RhsScalar,RhsStorageOrder,ConjugateRhs,ColMajor>
     52 {
     53 
     54 typedef typename scalar_product_traits<LhsScalar, RhsScalar>::ReturnType ResScalar;
     55 static void run(Index rows, Index cols, Index depth,
     56   const LhsScalar* _lhs, Index lhsStride,
     57   const RhsScalar* _rhs, Index rhsStride,
     58   ResScalar* res, Index resStride,
     59   ResScalar alpha,
     60   level3_blocking<LhsScalar,RhsScalar>& blocking,
     61   GemmParallelInfo<Index>* info = 0)
     62 {
     63   const_blas_data_mapper<LhsScalar, Index, LhsStorageOrder> lhs(_lhs,lhsStride);
     64   const_blas_data_mapper<RhsScalar, Index, RhsStorageOrder> rhs(_rhs,rhsStride);
     65 
     66   typedef gebp_traits<LhsScalar,RhsScalar> Traits;
     67 
     68   Index kc = blocking.kc();                   // cache block size along the K direction
     69   Index mc = (std::min)(rows,blocking.mc());  // cache block size along the M direction
     70   //Index nc = blocking.nc(); // cache block size along the N direction
     71 
     72   gemm_pack_lhs<LhsScalar, Index, Traits::mr, Traits::LhsProgress, LhsStorageOrder> pack_lhs;
     73   gemm_pack_rhs<RhsScalar, Index, Traits::nr, RhsStorageOrder> pack_rhs;
     74   gebp_kernel<LhsScalar, RhsScalar, Index, Traits::mr, Traits::nr, ConjugateLhs, ConjugateRhs> gebp;
     75 
     76 #ifdef EIGEN_HAS_OPENMP
     77   if(info)
     78   {
     79     // this is the parallel version!
     80     Index tid = omp_get_thread_num();
     81     Index threads = omp_get_num_threads();
     82 
     83     std::size_t sizeA = kc*mc;
     84     std::size_t sizeW = kc*Traits::WorkSpaceFactor;
     85     ei_declare_aligned_stack_constructed_variable(LhsScalar, blockA, sizeA, 0);
     86     ei_declare_aligned_stack_constructed_variable(RhsScalar, w, sizeW, 0);
     87 
     88     RhsScalar* blockB = blocking.blockB();
     89     eigen_internal_assert(blockB!=0);
     90 
     91     // For each horizontal panel of the rhs, and corresponding vertical panel of the lhs...
     92     for(Index k=0; k<depth; k+=kc)
     93     {
     94       const Index actual_kc = (std::min)(k+kc,depth)-k; // => rows of B', and cols of the A'
     95 
     96       // In order to reduce the chance that a thread has to wait for the other,
     97       // let's start by packing A'.
     98       pack_lhs(blockA, &lhs(0,k), lhsStride, actual_kc, mc);
     99 
    100       // Pack B_k to B' in a parallel fashion:
    101       // each thread packs the sub block B_k,j to B'_j where j is the thread id.
    102 
    103       // However, before copying to B'_j, we have to make sure that no other thread is still using it,
    104       // i.e., we test that info[tid].users equals 0.
    105       // Then, we set info[tid].users to the number of threads to mark that all other threads are going to use it.
    106       while(info[tid].users!=0) {}
    107       info[tid].users += threads;
    108 
    109       pack_rhs(blockB+info[tid].rhs_start*actual_kc, &rhs(k,info[tid].rhs_start), rhsStride, actual_kc, info[tid].rhs_length);
    110 
    111       // Notify the other threads that the part B'_j is ready to go.
    112       info[tid].sync = k;
    113 
    114       // Computes C_i += A' * B' per B'_j
    115       for(Index shift=0; shift<threads; ++shift)
    116       {
    117         Index j = (tid+shift)%threads;
    118 
    119         // At this point we have to make sure that B'_j has been updated by the thread j,
    120         // we use testAndSetOrdered to mimic a volatile access.
    121         // However, no need to wait for the B' part which has been updated by the current thread!
    122         if(shift>0)
    123           while(info[j].sync!=k) {}
    124 
    125         gebp(res+info[j].rhs_start*resStride, resStride, blockA, blockB+info[j].rhs_start*actual_kc, mc, actual_kc, info[j].rhs_length, alpha, -1,-1,0,0, w);
    126       }
    127 
    128       // Then keep going as usual with the remaining A'
    129       for(Index i=mc; i<rows; i+=mc)
    130       {
    131         const Index actual_mc = (std::min)(i+mc,rows)-i;
    132 
    133         // pack A_i,k to A'
    134         pack_lhs(blockA, &lhs(i,k), lhsStride, actual_kc, actual_mc);
    135 
    136         // C_i += A' * B'
    137         gebp(res+i, resStride, blockA, blockB, actual_mc, actual_kc, cols, alpha, -1,-1,0,0, w);
    138       }
    139 
    140       // Release all the sub blocks B'_j of B' for the current thread,
    141       // i.e., we simply decrement the number of users by 1
    142       for(Index j=0; j<threads; ++j)
    143         #pragma omp atomic
    144         --(info[j].users);
    145     }
    146   }
    147   else
    148 #endif // EIGEN_HAS_OPENMP
    149   {
    150     EIGEN_UNUSED_VARIABLE(info);
    151 
    152     // this is the sequential version!
    153     std::size_t sizeA = kc*mc;
    154     std::size_t sizeB = kc*cols;
    155     std::size_t sizeW = kc*Traits::WorkSpaceFactor;
    156 
    157     ei_declare_aligned_stack_constructed_variable(LhsScalar, blockA, sizeA, blocking.blockA());
    158     ei_declare_aligned_stack_constructed_variable(RhsScalar, blockB, sizeB, blocking.blockB());
    159     ei_declare_aligned_stack_constructed_variable(RhsScalar, blockW, sizeW, blocking.blockW());
    160 
    161     // For each horizontal panel of the rhs, and corresponding panel of the lhs...
    162     // (==GEMM_VAR1)
    163     for(Index k2=0; k2<depth; k2+=kc)
    164     {
    165       const Index actual_kc = (std::min)(k2+kc,depth)-k2;
    166 
    167       // OK, here we have selected one horizontal panel of rhs and one vertical panel of lhs.
    168       // => Pack rhs's panel into a sequential chunk of memory (L2 caching)
    169       // Note that this panel will be read as many times as the number of blocks in the lhs's
    170       // vertical panel which is, in practice, a very low number.
    171       pack_rhs(blockB, &rhs(k2,0), rhsStride, actual_kc, cols);
    172 
    173       // For each mc x kc block of the lhs's vertical panel...
    174       // (==GEPP_VAR1)
    175       for(Index i2=0; i2<rows; i2+=mc)
    176       {
    177         const Index actual_mc = (std::min)(i2+mc,rows)-i2;
    178 
    179         // We pack the lhs's block into a sequential chunk of memory (L1 caching)
    180         // Note that this block will be read a very high number of times, which is equal to the number of
    181         // micro vertical panel of the large rhs's panel (e.g., cols/4 times).
    182         pack_lhs(blockA, &lhs(i2,k2), lhsStride, actual_kc, actual_mc);
    183 
    184         // Everything is packed, we can now call the block * panel kernel:
    185         gebp(res+i2, resStride, blockA, blockB, actual_mc, actual_kc, cols, alpha, -1, -1, 0, 0, blockW);
    186       }
    187     }
    188   }
    189 }
    190 
    191 };
    192 
    193 /*********************************************************************************
    194 *  Specialization of GeneralProduct<> for "large" GEMM, i.e.,
    195 *  implementation of the high level wrapper to general_matrix_matrix_product
    196 **********************************************************************************/
    197 
    198 template<typename Lhs, typename Rhs>
    199 struct traits<GeneralProduct<Lhs,Rhs,GemmProduct> >
    200  : traits<ProductBase<GeneralProduct<Lhs,Rhs,GemmProduct>, Lhs, Rhs> >
    201 {};
    202 
    203 template<typename Scalar, typename Index, typename Gemm, typename Lhs, typename Rhs, typename Dest, typename BlockingType>
    204 struct gemm_functor
    205 {
    206   gemm_functor(const Lhs& lhs, const Rhs& rhs, Dest& dest, const Scalar& actualAlpha,
    207                   BlockingType& blocking)
    208     : m_lhs(lhs), m_rhs(rhs), m_dest(dest), m_actualAlpha(actualAlpha), m_blocking(blocking)
    209   {}
    210 
    211   void initParallelSession() const
    212   {
    213     m_blocking.allocateB();
    214   }
    215 
    216   void operator() (Index row, Index rows, Index col=0, Index cols=-1, GemmParallelInfo<Index>* info=0) const
    217   {
    218     if(cols==-1)
    219       cols = m_rhs.cols();
    220 
    221     Gemm::run(rows, cols, m_lhs.cols(),
    222               /*(const Scalar*)*/&m_lhs.coeffRef(row,0), m_lhs.outerStride(),
    223               /*(const Scalar*)*/&m_rhs.coeffRef(0,col), m_rhs.outerStride(),
    224               (Scalar*)&(m_dest.coeffRef(row,col)), m_dest.outerStride(),
    225               m_actualAlpha, m_blocking, info);
    226   }
    227 
    228   protected:
    229     const Lhs& m_lhs;
    230     const Rhs& m_rhs;
    231     Dest& m_dest;
    232     Scalar m_actualAlpha;
    233     BlockingType& m_blocking;
    234 };
    235 
    236 template<int StorageOrder, typename LhsScalar, typename RhsScalar, int MaxRows, int MaxCols, int MaxDepth, int KcFactor=1,
    237 bool FiniteAtCompileTime = MaxRows!=Dynamic && MaxCols!=Dynamic && MaxDepth != Dynamic> class gemm_blocking_space;
    238 
    239 template<typename _LhsScalar, typename _RhsScalar>
    240 class level3_blocking
    241 {
    242     typedef _LhsScalar LhsScalar;
    243     typedef _RhsScalar RhsScalar;
    244 
    245   protected:
    246     LhsScalar* m_blockA;
    247     RhsScalar* m_blockB;
    248     RhsScalar* m_blockW;
    249 
    250     DenseIndex m_mc;
    251     DenseIndex m_nc;
    252     DenseIndex m_kc;
    253 
    254   public:
    255 
    256     level3_blocking()
    257       : m_blockA(0), m_blockB(0), m_blockW(0), m_mc(0), m_nc(0), m_kc(0)
    258     {}
    259 
    260     inline DenseIndex mc() const { return m_mc; }
    261     inline DenseIndex nc() const { return m_nc; }
    262     inline DenseIndex kc() const { return m_kc; }
    263 
    264     inline LhsScalar* blockA() { return m_blockA; }
    265     inline RhsScalar* blockB() { return m_blockB; }
    266     inline RhsScalar* blockW() { return m_blockW; }
    267 };
    268 
    269 template<int StorageOrder, typename _LhsScalar, typename _RhsScalar, int MaxRows, int MaxCols, int MaxDepth, int KcFactor>
    270 class gemm_blocking_space<StorageOrder,_LhsScalar,_RhsScalar,MaxRows, MaxCols, MaxDepth, KcFactor, true>
    271   : public level3_blocking<
    272       typename conditional<StorageOrder==RowMajor,_RhsScalar,_LhsScalar>::type,
    273       typename conditional<StorageOrder==RowMajor,_LhsScalar,_RhsScalar>::type>
    274 {
    275     enum {
    276       Transpose = StorageOrder==RowMajor,
    277       ActualRows = Transpose ? MaxCols : MaxRows,
    278       ActualCols = Transpose ? MaxRows : MaxCols
    279     };
    280     typedef typename conditional<Transpose,_RhsScalar,_LhsScalar>::type LhsScalar;
    281     typedef typename conditional<Transpose,_LhsScalar,_RhsScalar>::type RhsScalar;
    282     typedef gebp_traits<LhsScalar,RhsScalar> Traits;
    283     enum {
    284       SizeA = ActualRows * MaxDepth,
    285       SizeB = ActualCols * MaxDepth,
    286       SizeW = MaxDepth * Traits::WorkSpaceFactor
    287     };
    288 
    289     EIGEN_ALIGN16 LhsScalar m_staticA[SizeA];
    290     EIGEN_ALIGN16 RhsScalar m_staticB[SizeB];
    291     EIGEN_ALIGN16 RhsScalar m_staticW[SizeW];
    292 
    293   public:
    294 
    295     gemm_blocking_space(DenseIndex /*rows*/, DenseIndex /*cols*/, DenseIndex /*depth*/)
    296     {
    297       this->m_mc = ActualRows;
    298       this->m_nc = ActualCols;
    299       this->m_kc = MaxDepth;
    300       this->m_blockA = m_staticA;
    301       this->m_blockB = m_staticB;
    302       this->m_blockW = m_staticW;
    303     }
    304 
    305     inline void allocateA() {}
    306     inline void allocateB() {}
    307     inline void allocateW() {}
    308     inline void allocateAll() {}
    309 };
    310 
    311 template<int StorageOrder, typename _LhsScalar, typename _RhsScalar, int MaxRows, int MaxCols, int MaxDepth, int KcFactor>
    312 class gemm_blocking_space<StorageOrder,_LhsScalar,_RhsScalar,MaxRows, MaxCols, MaxDepth, KcFactor, false>
    313   : public level3_blocking<
    314       typename conditional<StorageOrder==RowMajor,_RhsScalar,_LhsScalar>::type,
    315       typename conditional<StorageOrder==RowMajor,_LhsScalar,_RhsScalar>::type>
    316 {
    317     enum {
    318       Transpose = StorageOrder==RowMajor
    319     };
    320     typedef typename conditional<Transpose,_RhsScalar,_LhsScalar>::type LhsScalar;
    321     typedef typename conditional<Transpose,_LhsScalar,_RhsScalar>::type RhsScalar;
    322     typedef gebp_traits<LhsScalar,RhsScalar> Traits;
    323 
    324     DenseIndex m_sizeA;
    325     DenseIndex m_sizeB;
    326     DenseIndex m_sizeW;
    327 
    328   public:
    329 
    330     gemm_blocking_space(DenseIndex rows, DenseIndex cols, DenseIndex depth)
    331     {
    332       this->m_mc = Transpose ? cols : rows;
    333       this->m_nc = Transpose ? rows : cols;
    334       this->m_kc = depth;
    335 
    336       computeProductBlockingSizes<LhsScalar,RhsScalar,KcFactor>(this->m_kc, this->m_mc, this->m_nc);
    337       m_sizeA = this->m_mc * this->m_kc;
    338       m_sizeB = this->m_kc * this->m_nc;
    339       m_sizeW = this->m_kc*Traits::WorkSpaceFactor;
    340     }
    341 
    342     void allocateA()
    343     {
    344       if(this->m_blockA==0)
    345         this->m_blockA = aligned_new<LhsScalar>(m_sizeA);
    346     }
    347 
    348     void allocateB()
    349     {
    350       if(this->m_blockB==0)
    351         this->m_blockB = aligned_new<RhsScalar>(m_sizeB);
    352     }
    353 
    354     void allocateW()
    355     {
    356       if(this->m_blockW==0)
    357         this->m_blockW = aligned_new<RhsScalar>(m_sizeW);
    358     }
    359 
    360     void allocateAll()
    361     {
    362       allocateA();
    363       allocateB();
    364       allocateW();
    365     }
    366 
    367     ~gemm_blocking_space()
    368     {
    369       aligned_delete(this->m_blockA, m_sizeA);
    370       aligned_delete(this->m_blockB, m_sizeB);
    371       aligned_delete(this->m_blockW, m_sizeW);
    372     }
    373 };
    374 
    375 } // end namespace internal
    376 
    377 template<typename Lhs, typename Rhs>
    378 class GeneralProduct<Lhs, Rhs, GemmProduct>
    379   : public ProductBase<GeneralProduct<Lhs,Rhs,GemmProduct>, Lhs, Rhs>
    380 {
    381     enum {
    382       MaxDepthAtCompileTime = EIGEN_SIZE_MIN_PREFER_FIXED(Lhs::MaxColsAtCompileTime,Rhs::MaxRowsAtCompileTime)
    383     };
    384   public:
    385     EIGEN_PRODUCT_PUBLIC_INTERFACE(GeneralProduct)
    386 
    387     typedef typename  Lhs::Scalar LhsScalar;
    388     typedef typename  Rhs::Scalar RhsScalar;
    389     typedef           Scalar      ResScalar;
    390 
    391     GeneralProduct(const Lhs& lhs, const Rhs& rhs) : Base(lhs,rhs)
    392     {
    393       typedef internal::scalar_product_op<LhsScalar,RhsScalar> BinOp;
    394       EIGEN_CHECK_BINARY_COMPATIBILIY(BinOp,LhsScalar,RhsScalar);
    395     }
    396 
    397     template<typename Dest> void scaleAndAddTo(Dest& dst, const Scalar& alpha) const
    398     {
    399       eigen_assert(dst.rows()==m_lhs.rows() && dst.cols()==m_rhs.cols());
    400 
    401       typename internal::add_const_on_value_type<ActualLhsType>::type lhs = LhsBlasTraits::extract(m_lhs);
    402       typename internal::add_const_on_value_type<ActualRhsType>::type rhs = RhsBlasTraits::extract(m_rhs);
    403 
    404       Scalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(m_lhs)
    405                                  * RhsBlasTraits::extractScalarFactor(m_rhs);
    406 
    407       typedef internal::gemm_blocking_space<(Dest::Flags&RowMajorBit) ? RowMajor : ColMajor,LhsScalar,RhsScalar,
    408               Dest::MaxRowsAtCompileTime,Dest::MaxColsAtCompileTime,MaxDepthAtCompileTime> BlockingType;
    409 
    410       typedef internal::gemm_functor<
    411         Scalar, Index,
    412         internal::general_matrix_matrix_product<
    413           Index,
    414           LhsScalar, (_ActualLhsType::Flags&RowMajorBit) ? RowMajor : ColMajor, bool(LhsBlasTraits::NeedToConjugate),
    415           RhsScalar, (_ActualRhsType::Flags&RowMajorBit) ? RowMajor : ColMajor, bool(RhsBlasTraits::NeedToConjugate),
    416           (Dest::Flags&RowMajorBit) ? RowMajor : ColMajor>,
    417         _ActualLhsType, _ActualRhsType, Dest, BlockingType> GemmFunctor;
    418 
    419       BlockingType blocking(dst.rows(), dst.cols(), lhs.cols());
    420 
    421       internal::parallelize_gemm<(Dest::MaxRowsAtCompileTime>32 || Dest::MaxRowsAtCompileTime==Dynamic)>(GemmFunctor(lhs, rhs, dst, actualAlpha, blocking), this->rows(), this->cols(), Dest::Flags&RowMajorBit);
    422     }
    423 };
    424 
    425 } // end namespace Eigen
    426 
    427 #endif // EIGEN_GENERAL_MATRIX_MATRIX_H
    428