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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008-2015 Gael Guennebaud <gael.guennebaud@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_SPARSEDENSEPRODUCT_H
11 #define EIGEN_SPARSEDENSEPRODUCT_H
12 
13 namespace Eigen {
14 
15 namespace internal {
16 
17 template <> struct product_promote_storage_type<Sparse,Dense, OuterProduct> { typedef Sparse ret; };
18 template <> struct product_promote_storage_type<Dense,Sparse, OuterProduct> { typedef Sparse ret; };
19 
20 template<typename SparseLhsType, typename DenseRhsType, typename DenseResType,
21          typename AlphaType,
22          int LhsStorageOrder = ((SparseLhsType::Flags&RowMajorBit)==RowMajorBit) ? RowMajor : ColMajor,
23          bool ColPerCol = ((DenseRhsType::Flags&RowMajorBit)==0) || DenseRhsType::ColsAtCompileTime==1>
24 struct sparse_time_dense_product_impl;
25 
26 template<typename SparseLhsType, typename DenseRhsType, typename DenseResType>
27 struct sparse_time_dense_product_impl<SparseLhsType,DenseRhsType,DenseResType, typename DenseResType::Scalar, RowMajor, true>
28 {
29   typedef typename internal::remove_all<SparseLhsType>::type Lhs;
30   typedef typename internal::remove_all<DenseRhsType>::type Rhs;
31   typedef typename internal::remove_all<DenseResType>::type Res;
32   typedef typename evaluator<Lhs>::InnerIterator LhsInnerIterator;
33   typedef evaluator<Lhs> LhsEval;
34   static void run(const SparseLhsType& lhs, const DenseRhsType& rhs, DenseResType& res, const typename Res::Scalar& alpha)
35   {
36     LhsEval lhsEval(lhs);
37 
38     Index n = lhs.outerSize();
39 #ifdef EIGEN_HAS_OPENMP
40     Eigen::initParallel();
41     Index threads = Eigen::nbThreads();
42 #endif
43 
44     for(Index c=0; c<rhs.cols(); ++c)
45     {
46 #ifdef EIGEN_HAS_OPENMP
47       // This 20000 threshold has been found experimentally on 2D and 3D Poisson problems.
48       // It basically represents the minimal amount of work to be done to be worth it.
49       if(threads>1 && lhsEval.nonZerosEstimate() > 20000)
50       {
51         #pragma omp parallel for schedule(dynamic,(n+threads*4-1)/(threads*4)) num_threads(threads)
52         for(Index i=0; i<n; ++i)
53           processRow(lhsEval,rhs,res,alpha,i,c);
54       }
55       else
56 #endif
57       {
58         for(Index i=0; i<n; ++i)
59           processRow(lhsEval,rhs,res,alpha,i,c);
60       }
61     }
62   }
63 
64   static void processRow(const LhsEval& lhsEval, const DenseRhsType& rhs, DenseResType& res, const typename Res::Scalar& alpha, Index i, Index col)
65   {
66     typename Res::Scalar tmp(0);
67     for(LhsInnerIterator it(lhsEval,i); it ;++it)
68       tmp += it.value() * rhs.coeff(it.index(),col);
69     res.coeffRef(i,col) += alpha * tmp;
70   }
71 
72 };
73 
74 // FIXME: what is the purpose of the following specialization? Is it for the BlockedSparse format?
75 // -> let's disable it for now as it is conflicting with generic scalar*matrix and matrix*scalar operators
76 // template<typename T1, typename T2/*, int _Options, typename _StrideType*/>
77 // struct ScalarBinaryOpTraits<T1, Ref<T2/*, _Options, _StrideType*/> >
78 // {
79 //   enum {
80 //     Defined = 1
81 //   };
82 //   typedef typename CwiseUnaryOp<scalar_multiple2_op<T1, typename T2::Scalar>, T2>::PlainObject ReturnType;
83 // };
84 
85 template<typename SparseLhsType, typename DenseRhsType, typename DenseResType, typename AlphaType>
86 struct sparse_time_dense_product_impl<SparseLhsType,DenseRhsType,DenseResType, AlphaType, ColMajor, true>
87 {
88   typedef typename internal::remove_all<SparseLhsType>::type Lhs;
89   typedef typename internal::remove_all<DenseRhsType>::type Rhs;
90   typedef typename internal::remove_all<DenseResType>::type Res;
91   typedef typename evaluator<Lhs>::InnerIterator LhsInnerIterator;
92   static void run(const SparseLhsType& lhs, const DenseRhsType& rhs, DenseResType& res, const AlphaType& alpha)
93   {
94     evaluator<Lhs> lhsEval(lhs);
95     for(Index c=0; c<rhs.cols(); ++c)
96     {
97       for(Index j=0; j<lhs.outerSize(); ++j)
98       {
99 //        typename Res::Scalar rhs_j = alpha * rhs.coeff(j,c);
100         typename ScalarBinaryOpTraits<AlphaType, typename Rhs::Scalar>::ReturnType rhs_j(alpha * rhs.coeff(j,c));
101         for(LhsInnerIterator it(lhsEval,j); it ;++it)
102           res.coeffRef(it.index(),c) += it.value() * rhs_j;
103       }
104     }
105   }
106 };
107 
108 template<typename SparseLhsType, typename DenseRhsType, typename DenseResType>
109 struct sparse_time_dense_product_impl<SparseLhsType,DenseRhsType,DenseResType, typename DenseResType::Scalar, RowMajor, false>
110 {
111   typedef typename internal::remove_all<SparseLhsType>::type Lhs;
112   typedef typename internal::remove_all<DenseRhsType>::type Rhs;
113   typedef typename internal::remove_all<DenseResType>::type Res;
114   typedef typename evaluator<Lhs>::InnerIterator LhsInnerIterator;
115   static void run(const SparseLhsType& lhs, const DenseRhsType& rhs, DenseResType& res, const typename Res::Scalar& alpha)
116   {
117     evaluator<Lhs> lhsEval(lhs);
118     for(Index j=0; j<lhs.outerSize(); ++j)
119     {
120       typename Res::RowXpr res_j(res.row(j));
121       for(LhsInnerIterator it(lhsEval,j); it ;++it)
122         res_j += (alpha*it.value()) * rhs.row(it.index());
123     }
124   }
125 };
126 
127 template<typename SparseLhsType, typename DenseRhsType, typename DenseResType>
128 struct sparse_time_dense_product_impl<SparseLhsType,DenseRhsType,DenseResType, typename DenseResType::Scalar, ColMajor, false>
129 {
130   typedef typename internal::remove_all<SparseLhsType>::type Lhs;
131   typedef typename internal::remove_all<DenseRhsType>::type Rhs;
132   typedef typename internal::remove_all<DenseResType>::type Res;
133   typedef typename evaluator<Lhs>::InnerIterator LhsInnerIterator;
134   static void run(const SparseLhsType& lhs, const DenseRhsType& rhs, DenseResType& res, const typename Res::Scalar& alpha)
135   {
136     evaluator<Lhs> lhsEval(lhs);
137     for(Index j=0; j<lhs.outerSize(); ++j)
138     {
139       typename Rhs::ConstRowXpr rhs_j(rhs.row(j));
140       for(LhsInnerIterator it(lhsEval,j); it ;++it)
141         res.row(it.index()) += (alpha*it.value()) * rhs_j;
142     }
143   }
144 };
145 
146 template<typename SparseLhsType, typename DenseRhsType, typename DenseResType,typename AlphaType>
147 inline void sparse_time_dense_product(const SparseLhsType& lhs, const DenseRhsType& rhs, DenseResType& res, const AlphaType& alpha)
148 {
149   sparse_time_dense_product_impl<SparseLhsType,DenseRhsType,DenseResType, AlphaType>::run(lhs, rhs, res, alpha);
150 }
151 
152 } // end namespace internal
153 
154 namespace internal {
155 
156 template<typename Lhs, typename Rhs, int ProductType>
157 struct generic_product_impl<Lhs, Rhs, SparseShape, DenseShape, ProductType>
158  : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,SparseShape,DenseShape,ProductType> >
159 {
160   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
161 
162   template<typename Dest>
163   static void scaleAndAddTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
164   {
165     typedef typename nested_eval<Lhs,((Rhs::Flags&RowMajorBit)==0) ? 1 : Rhs::ColsAtCompileTime>::type LhsNested;
166     typedef typename nested_eval<Rhs,((Lhs::Flags&RowMajorBit)==0) ? 1 : Dynamic>::type RhsNested;
167     LhsNested lhsNested(lhs);
168     RhsNested rhsNested(rhs);
169     internal::sparse_time_dense_product(lhsNested, rhsNested, dst, alpha);
170   }
171 };
172 
173 template<typename Lhs, typename Rhs, int ProductType>
174 struct generic_product_impl<Lhs, Rhs, SparseTriangularShape, DenseShape, ProductType>
175   : generic_product_impl<Lhs, Rhs, SparseShape, DenseShape, ProductType>
176 {};
177 
178 template<typename Lhs, typename Rhs, int ProductType>
179 struct generic_product_impl<Lhs, Rhs, DenseShape, SparseShape, ProductType>
180   : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,DenseShape,SparseShape,ProductType> >
181 {
182   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
183 
184   template<typename Dst>
185   static void scaleAndAddTo(Dst& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
186   {
187     typedef typename nested_eval<Lhs,((Rhs::Flags&RowMajorBit)==0) ? Dynamic : 1>::type LhsNested;
188     typedef typename nested_eval<Rhs,((Lhs::Flags&RowMajorBit)==RowMajorBit) ? 1 : Lhs::RowsAtCompileTime>::type RhsNested;
189     LhsNested lhsNested(lhs);
190     RhsNested rhsNested(rhs);
191 
192     // transpose everything
193     Transpose<Dst> dstT(dst);
194     internal::sparse_time_dense_product(rhsNested.transpose(), lhsNested.transpose(), dstT, alpha);
195   }
196 };
197 
198 template<typename Lhs, typename Rhs, int ProductType>
199 struct generic_product_impl<Lhs, Rhs, DenseShape, SparseTriangularShape, ProductType>
200   : generic_product_impl<Lhs, Rhs, DenseShape, SparseShape, ProductType>
201 {};
202 
203 template<typename LhsT, typename RhsT, bool NeedToTranspose>
204 struct sparse_dense_outer_product_evaluator
205 {
206 protected:
207   typedef typename conditional<NeedToTranspose,RhsT,LhsT>::type Lhs1;
208   typedef typename conditional<NeedToTranspose,LhsT,RhsT>::type ActualRhs;
209   typedef Product<LhsT,RhsT,DefaultProduct> ProdXprType;
210 
211   // if the actual left-hand side is a dense vector,
212   // then build a sparse-view so that we can seamlessly iterate over it.
213   typedef typename conditional<is_same<typename internal::traits<Lhs1>::StorageKind,Sparse>::value,
214             Lhs1, SparseView<Lhs1> >::type ActualLhs;
215   typedef typename conditional<is_same<typename internal::traits<Lhs1>::StorageKind,Sparse>::value,
216             Lhs1 const&, SparseView<Lhs1> >::type LhsArg;
217 
218   typedef evaluator<ActualLhs> LhsEval;
219   typedef evaluator<ActualRhs> RhsEval;
220   typedef typename evaluator<ActualLhs>::InnerIterator LhsIterator;
221   typedef typename ProdXprType::Scalar Scalar;
222 
223 public:
224   enum {
225     Flags = NeedToTranspose ? RowMajorBit : 0,
226     CoeffReadCost = HugeCost
227   };
228 
229   class InnerIterator : public LhsIterator
230   {
231   public:
232     InnerIterator(const sparse_dense_outer_product_evaluator &xprEval, Index outer)
233       : LhsIterator(xprEval.m_lhsXprImpl, 0),
234         m_outer(outer),
235         m_empty(false),
236         m_factor(get(xprEval.m_rhsXprImpl, outer, typename internal::traits<ActualRhs>::StorageKind() ))
237     {}
238 
239     EIGEN_STRONG_INLINE Index outer() const { return m_outer; }
240     EIGEN_STRONG_INLINE Index row()   const { return NeedToTranspose ? m_outer : LhsIterator::index(); }
241     EIGEN_STRONG_INLINE Index col()   const { return NeedToTranspose ? LhsIterator::index() : m_outer; }
242 
243     EIGEN_STRONG_INLINE Scalar value() const { return LhsIterator::value() * m_factor; }
244     EIGEN_STRONG_INLINE operator bool() const { return LhsIterator::operator bool() && (!m_empty); }
245 
246   protected:
247     Scalar get(const RhsEval &rhs, Index outer, Dense = Dense()) const
248     {
249       return rhs.coeff(outer);
250     }
251 
252     Scalar get(const RhsEval &rhs, Index outer, Sparse = Sparse())
253     {
254       typename RhsEval::InnerIterator it(rhs, outer);
255       if (it && it.index()==0 && it.value()!=Scalar(0))
256         return it.value();
257       m_empty = true;
258       return Scalar(0);
259     }
260 
261     Index m_outer;
262     bool m_empty;
263     Scalar m_factor;
264   };
265 
266   sparse_dense_outer_product_evaluator(const Lhs1 &lhs, const ActualRhs &rhs)
267      : m_lhs(lhs), m_lhsXprImpl(m_lhs), m_rhsXprImpl(rhs)
268   {
269     EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
270   }
271 
272   // transpose case
273   sparse_dense_outer_product_evaluator(const ActualRhs &rhs, const Lhs1 &lhs)
274      : m_lhs(lhs), m_lhsXprImpl(m_lhs), m_rhsXprImpl(rhs)
275   {
276     EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
277   }
278 
279 protected:
280   const LhsArg m_lhs;
281   evaluator<ActualLhs> m_lhsXprImpl;
282   evaluator<ActualRhs> m_rhsXprImpl;
283 };
284 
285 // sparse * dense outer product
286 template<typename Lhs, typename Rhs>
287 struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, OuterProduct, SparseShape, DenseShape>
288   : sparse_dense_outer_product_evaluator<Lhs,Rhs, Lhs::IsRowMajor>
289 {
290   typedef sparse_dense_outer_product_evaluator<Lhs,Rhs, Lhs::IsRowMajor> Base;
291 
292   typedef Product<Lhs, Rhs> XprType;
293   typedef typename XprType::PlainObject PlainObject;
294 
295   explicit product_evaluator(const XprType& xpr)
296     : Base(xpr.lhs(), xpr.rhs())
297   {}
298 
299 };
300 
301 template<typename Lhs, typename Rhs>
302 struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, OuterProduct, DenseShape, SparseShape>
303   : sparse_dense_outer_product_evaluator<Lhs,Rhs, Rhs::IsRowMajor>
304 {
305   typedef sparse_dense_outer_product_evaluator<Lhs,Rhs, Rhs::IsRowMajor> Base;
306 
307   typedef Product<Lhs, Rhs> XprType;
308   typedef typename XprType::PlainObject PlainObject;
309 
310   explicit product_evaluator(const XprType& xpr)
311     : Base(xpr.lhs(), xpr.rhs())
312   {}
313 
314 };
315 
316 } // end namespace internal
317 
318 } // end namespace Eigen
319 
320 #endif // EIGEN_SPARSEDENSEPRODUCT_H
321