1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2010 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_SPARSE_SOLVE_H
11 #define EIGEN_SPARSE_SOLVE_H
12 
13 namespace Eigen {
14 
15 namespace internal {
16 
17 template<typename _DecompositionType, typename Rhs> struct sparse_solve_retval_base;
18 template<typename _DecompositionType, typename Rhs> struct sparse_solve_retval;
19 
20 template<typename DecompositionType, typename Rhs>
21 struct traits<sparse_solve_retval_base<DecompositionType, Rhs> >
22 {
23   typedef typename DecompositionType::MatrixType MatrixType;
24   typedef SparseMatrix<typename Rhs::Scalar, Rhs::Options, typename Rhs::Index> ReturnType;
25 };
26 
27 template<typename _DecompositionType, typename Rhs> struct sparse_solve_retval_base
28  : public ReturnByValue<sparse_solve_retval_base<_DecompositionType, Rhs> >
29 {
30   typedef typename remove_all<typename Rhs::Nested>::type RhsNestedCleaned;
31   typedef _DecompositionType DecompositionType;
32   typedef ReturnByValue<sparse_solve_retval_base> Base;
33   typedef typename Base::Index Index;
34 
35   sparse_solve_retval_base(const DecompositionType& dec, const Rhs& rhs)
36     : m_dec(dec), m_rhs(rhs)
37   {}
38 
39   inline Index rows() const { return m_dec.cols(); }
40   inline Index cols() const { return m_rhs.cols(); }
41   inline const DecompositionType& dec() const { return m_dec; }
42   inline const RhsNestedCleaned& rhs() const { return m_rhs; }
43 
44   template<typename Dest> inline void evalTo(Dest& dst) const
45   {
46     static_cast<const sparse_solve_retval<DecompositionType,Rhs>*>(this)->evalTo(dst);
47   }
48 
49   protected:
50     template<typename DestScalar, int DestOptions, typename DestIndex>
51     inline void defaultEvalTo(SparseMatrix<DestScalar,DestOptions,DestIndex>& dst) const
52     {
53       // we process the sparse rhs per block of NbColsAtOnce columns temporarily stored into a dense matrix.
54       static const int NbColsAtOnce = 4;
55       int rhsCols = m_rhs.cols();
56       int size = m_rhs.rows();
57       Eigen::Matrix<DestScalar,Dynamic,Dynamic> tmp(size,rhsCols);
58       Eigen::Matrix<DestScalar,Dynamic,Dynamic> tmpX(size,rhsCols);
59       for(int k=0; k<rhsCols; k+=NbColsAtOnce)
60       {
61         int actualCols = std::min<int>(rhsCols-k, NbColsAtOnce);
62         tmp.leftCols(actualCols) = m_rhs.middleCols(k,actualCols);
63         tmpX.leftCols(actualCols) = m_dec.solve(tmp.leftCols(actualCols));
64         dst.middleCols(k,actualCols) = tmpX.leftCols(actualCols).sparseView();
65       }
66     }
67     const DecompositionType& m_dec;
68     typename Rhs::Nested m_rhs;
69 };
70 
71 #define EIGEN_MAKE_SPARSE_SOLVE_HELPERS(DecompositionType,Rhs) \
72   typedef typename DecompositionType::MatrixType MatrixType; \
73   typedef typename MatrixType::Scalar Scalar; \
74   typedef typename MatrixType::RealScalar RealScalar; \
75   typedef typename MatrixType::Index Index; \
76   typedef Eigen::internal::sparse_solve_retval_base<DecompositionType,Rhs> Base; \
77   using Base::dec; \
78   using Base::rhs; \
79   using Base::rows; \
80   using Base::cols; \
81   sparse_solve_retval(const DecompositionType& dec, const Rhs& rhs) \
82     : Base(dec, rhs) {}
83 
84 
85 
86 template<typename DecompositionType, typename Rhs, typename Guess> struct solve_retval_with_guess;
87 
88 template<typename DecompositionType, typename Rhs, typename Guess>
89 struct traits<solve_retval_with_guess<DecompositionType, Rhs, Guess> >
90 {
91   typedef typename DecompositionType::MatrixType MatrixType;
92   typedef Matrix<typename Rhs::Scalar,
93                  MatrixType::ColsAtCompileTime,
94                  Rhs::ColsAtCompileTime,
95                  Rhs::PlainObject::Options,
96                  MatrixType::MaxColsAtCompileTime,
97                  Rhs::MaxColsAtCompileTime> ReturnType;
98 };
99 
100 template<typename DecompositionType, typename Rhs, typename Guess> struct solve_retval_with_guess
101  : public ReturnByValue<solve_retval_with_guess<DecompositionType, Rhs, Guess> >
102 {
103   typedef typename DecompositionType::Index Index;
104 
105   solve_retval_with_guess(const DecompositionType& dec, const Rhs& rhs, const Guess& guess)
106     : m_dec(dec), m_rhs(rhs), m_guess(guess)
107   {}
108 
109   inline Index rows() const { return m_dec.cols(); }
110   inline Index cols() const { return m_rhs.cols(); }
111 
112   template<typename Dest> inline void evalTo(Dest& dst) const
113   {
114     dst = m_guess;
115     m_dec._solveWithGuess(m_rhs,dst);
116   }
117 
118   protected:
119     const DecompositionType& m_dec;
120     const typename Rhs::Nested m_rhs;
121     const typename Guess::Nested m_guess;
122 };
123 
124 } // namepsace internal
125 
126 } // end namespace Eigen
127 
128 #endif // EIGEN_SPARSE_SOLVE_H
129