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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@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 once 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 EIGEN_DEVICE_FUNC
31 void run(
32   Index size,
33   const Scalar*  lhs, Index lhsStride,
34   const Scalar*  rhs,
35   Scalar* res,
36   Scalar alpha);
37 };
38 
39 template<typename Scalar, typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs, int Version>
40 EIGEN_DONT_INLINE EIGEN_DEVICE_FUNC
run(Index size,const Scalar * lhs,Index lhsStride,const Scalar * rhs,Scalar * res,Scalar alpha)41 void selfadjoint_matrix_vector_product<Scalar,Index,StorageOrder,UpLo,ConjugateLhs,ConjugateRhs,Version>::run(
42   Index size,
43   const Scalar*  lhs, Index lhsStride,
44   const Scalar*  rhs,
45   Scalar* res,
46   Scalar alpha)
47 {
48   typedef typename packet_traits<Scalar>::type Packet;
49   typedef typename NumTraits<Scalar>::Real RealScalar;
50   const Index PacketSize = sizeof(Packet)/sizeof(Scalar);
51 
52   enum {
53     IsRowMajor = StorageOrder==RowMajor ? 1 : 0,
54     IsLower = UpLo == Lower ? 1 : 0,
55     FirstTriangular = IsRowMajor == IsLower
56   };
57 
58   conj_helper<Scalar,Scalar,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs,  IsRowMajor), ConjugateRhs> cj0;
59   conj_helper<Scalar,Scalar,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs, !IsRowMajor), ConjugateRhs> cj1;
60   conj_helper<RealScalar,Scalar,false, ConjugateRhs> cjd;
61 
62   conj_helper<Packet,Packet,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs,  IsRowMajor), ConjugateRhs> pcj0;
63   conj_helper<Packet,Packet,NumTraits<Scalar>::IsComplex && EIGEN_LOGICAL_XOR(ConjugateLhs, !IsRowMajor), ConjugateRhs> pcj1;
64 
65   Scalar cjAlpha = ConjugateRhs ? numext::conj(alpha) : alpha;
66 
67   Index bound = numext::maxi(Index(0), size-8) & 0xfffffffe;
68   if (FirstTriangular)
69     bound = size - bound;
70 
71   for (Index j=FirstTriangular ? bound : 0;
72        j<(FirstTriangular ? size : bound);j+=2)
73   {
74     const Scalar* EIGEN_RESTRICT A0 = lhs + j*lhsStride;
75     const Scalar* EIGEN_RESTRICT A1 = lhs + (j+1)*lhsStride;
76 
77     Scalar t0 = cjAlpha * rhs[j];
78     Packet ptmp0 = pset1<Packet>(t0);
79     Scalar t1 = cjAlpha * rhs[j+1];
80     Packet ptmp1 = pset1<Packet>(t1);
81 
82     Scalar t2(0);
83     Packet ptmp2 = pset1<Packet>(t2);
84     Scalar t3(0);
85     Packet ptmp3 = pset1<Packet>(t3);
86 
87     Index starti = FirstTriangular ? 0 : j+2;
88     Index endi   = FirstTriangular ? j : size;
89     Index alignedStart = (starti) + internal::first_default_aligned(&res[starti], endi-starti);
90     Index alignedEnd = alignedStart + ((endi-alignedStart)/(PacketSize))*(PacketSize);
91 
92     res[j]   += cjd.pmul(numext::real(A0[j]), t0);
93     res[j+1] += cjd.pmul(numext::real(A1[j+1]), t1);
94     if(FirstTriangular)
95     {
96       res[j]   += cj0.pmul(A1[j],   t1);
97       t3       += cj1.pmul(A1[j],   rhs[j]);
98     }
99     else
100     {
101       res[j+1] += cj0.pmul(A0[j+1],t0);
102       t2 += cj1.pmul(A0[j+1], rhs[j+1]);
103     }
104 
105     for (Index i=starti; i<alignedStart; ++i)
106     {
107       res[i] += cj0.pmul(A0[i], t0) + cj0.pmul(A1[i],t1);
108       t2 += cj1.pmul(A0[i], rhs[i]);
109       t3 += cj1.pmul(A1[i], rhs[i]);
110     }
111     // Yes this an optimization for gcc 4.3 and 4.4 (=> huge speed up)
112     // gcc 4.2 does this optimization automatically.
113     const Scalar* EIGEN_RESTRICT a0It  = A0  + alignedStart;
114     const Scalar* EIGEN_RESTRICT a1It  = A1  + alignedStart;
115     const Scalar* EIGEN_RESTRICT rhsIt = rhs + alignedStart;
116           Scalar* EIGEN_RESTRICT resIt = res + alignedStart;
117     for (Index i=alignedStart; i<alignedEnd; i+=PacketSize)
118     {
119       Packet A0i = ploadu<Packet>(a0It);  a0It  += PacketSize;
120       Packet A1i = ploadu<Packet>(a1It);  a1It  += PacketSize;
121       Packet Bi  = ploadu<Packet>(rhsIt); rhsIt += PacketSize; // FIXME should be aligned in most cases
122       Packet Xi  = pload <Packet>(resIt);
123 
124       Xi    = pcj0.pmadd(A0i,ptmp0, pcj0.pmadd(A1i,ptmp1,Xi));
125       ptmp2 = pcj1.pmadd(A0i,  Bi, ptmp2);
126       ptmp3 = pcj1.pmadd(A1i,  Bi, ptmp3);
127       pstore(resIt,Xi); resIt += PacketSize;
128     }
129     for (Index i=alignedEnd; i<endi; i++)
130     {
131       res[i] += cj0.pmul(A0[i], t0) + cj0.pmul(A1[i],t1);
132       t2 += cj1.pmul(A0[i], rhs[i]);
133       t3 += cj1.pmul(A1[i], rhs[i]);
134     }
135 
136     res[j]   += alpha * (t2 + predux(ptmp2));
137     res[j+1] += alpha * (t3 + predux(ptmp3));
138   }
139   for (Index j=FirstTriangular ? 0 : bound;j<(FirstTriangular ? bound : size);j++)
140   {
141     const Scalar* EIGEN_RESTRICT A0 = lhs + j*lhsStride;
142 
143     Scalar t1 = cjAlpha * rhs[j];
144     Scalar t2(0);
145     res[j] += cjd.pmul(numext::real(A0[j]), t1);
146     for (Index i=FirstTriangular ? 0 : j+1; i<(FirstTriangular ? j : size); i++)
147     {
148       res[i] += cj0.pmul(A0[i], t1);
149       t2 += cj1.pmul(A0[i], rhs[i]);
150     }
151     res[j] += alpha * t2;
152   }
153 }
154 
155 } // end namespace internal
156 
157 /***************************************************************************
158 * Wrapper to product_selfadjoint_vector
159 ***************************************************************************/
160 
161 namespace internal {
162 
163 template<typename Lhs, int LhsMode, typename Rhs>
164 struct selfadjoint_product_impl<Lhs,LhsMode,false,Rhs,0,true>
165 {
166   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
167 
168   typedef internal::blas_traits<Lhs> LhsBlasTraits;
169   typedef typename LhsBlasTraits::DirectLinearAccessType ActualLhsType;
170   typedef typename internal::remove_all<ActualLhsType>::type ActualLhsTypeCleaned;
171 
172   typedef internal::blas_traits<Rhs> RhsBlasTraits;
173   typedef typename RhsBlasTraits::DirectLinearAccessType ActualRhsType;
174   typedef typename internal::remove_all<ActualRhsType>::type ActualRhsTypeCleaned;
175 
176   enum { LhsUpLo = LhsMode&(Upper|Lower) };
177 
178   template<typename Dest>
179   static EIGEN_DEVICE_FUNC
180   void run(Dest& dest, const Lhs &a_lhs, const Rhs &a_rhs, const Scalar& alpha)
181   {
182     typedef typename Dest::Scalar ResScalar;
183     typedef typename Rhs::Scalar RhsScalar;
184     typedef Map<Matrix<ResScalar,Dynamic,1>, EIGEN_PLAIN_ENUM_MIN(AlignedMax,internal::packet_traits<ResScalar>::size)> MappedDest;
185 
186     eigen_assert(dest.rows()==a_lhs.rows() && dest.cols()==a_rhs.cols());
187 
188     typename internal::add_const_on_value_type<ActualLhsType>::type lhs = LhsBlasTraits::extract(a_lhs);
189     typename internal::add_const_on_value_type<ActualRhsType>::type rhs = RhsBlasTraits::extract(a_rhs);
190 
191     Scalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(a_lhs)
192                                * RhsBlasTraits::extractScalarFactor(a_rhs);
193 
194     enum {
195       EvalToDest = (Dest::InnerStrideAtCompileTime==1),
196       UseRhs = (ActualRhsTypeCleaned::InnerStrideAtCompileTime==1)
197     };
198 
199     internal::gemv_static_vector_if<ResScalar,Dest::SizeAtCompileTime,Dest::MaxSizeAtCompileTime,!EvalToDest> static_dest;
200     internal::gemv_static_vector_if<RhsScalar,ActualRhsTypeCleaned::SizeAtCompileTime,ActualRhsTypeCleaned::MaxSizeAtCompileTime,!UseRhs> static_rhs;
201 
202     ei_declare_aligned_stack_constructed_variable(ResScalar,actualDestPtr,dest.size(),
203                                                   EvalToDest ? dest.data() : static_dest.data());
204 
205     ei_declare_aligned_stack_constructed_variable(RhsScalar,actualRhsPtr,rhs.size(),
206         UseRhs ? const_cast<RhsScalar*>(rhs.data()) : static_rhs.data());
207 
208     if(!EvalToDest)
209     {
210       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
211       Index size = dest.size();
212       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
213       #endif
214       MappedDest(actualDestPtr, dest.size()) = dest;
215     }
216 
217     if(!UseRhs)
218     {
219       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
220       Index size = rhs.size();
221       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
222       #endif
223       Map<typename ActualRhsTypeCleaned::PlainObject>(actualRhsPtr, rhs.size()) = rhs;
224     }
225 
226 
227     internal::selfadjoint_matrix_vector_product<Scalar, Index, (internal::traits<ActualLhsTypeCleaned>::Flags&RowMajorBit) ? RowMajor : ColMajor,
228                                                 int(LhsUpLo), bool(LhsBlasTraits::NeedToConjugate), bool(RhsBlasTraits::NeedToConjugate)>::run
229       (
230         lhs.rows(),                             // size
231         &lhs.coeffRef(0,0),  lhs.outerStride(), // lhs info
232         actualRhsPtr,                           // rhs info
233         actualDestPtr,                          // result info
234         actualAlpha                             // scale factor
235       );
236 
237     if(!EvalToDest)
238       dest = MappedDest(actualDestPtr, dest.size());
239   }
240 };
241 
242 template<typename Lhs, typename Rhs, int RhsMode>
243 struct selfadjoint_product_impl<Lhs,0,true,Rhs,RhsMode,false>
244 {
245   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
246   enum { RhsUpLo = RhsMode&(Upper|Lower)  };
247 
248   template<typename Dest>
249   static void run(Dest& dest, const Lhs &a_lhs, const Rhs &a_rhs, const Scalar& alpha)
250   {
251     // let's simply transpose the product
252     Transpose<Dest> destT(dest);
253     selfadjoint_product_impl<Transpose<const Rhs>, int(RhsUpLo)==Upper ? Lower : Upper, false,
254                              Transpose<const Lhs>, 0, true>::run(destT, a_rhs.transpose(), a_lhs.transpose(), alpha);
255   }
256 };
257 
258 } // end namespace internal
259 
260 } // end namespace Eigen
261 
262 #endif // EIGEN_SELFADJOINT_MATRIX_VECTOR_H
263