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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 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_SPARSE_TRIANGULARVIEW_H
11 #define EIGEN_SPARSE_TRIANGULARVIEW_H
12 
13 namespace Eigen {
14 
15 namespace internal {
16 
17 template<typename MatrixType, int Mode>
18 struct traits<SparseTriangularView<MatrixType,Mode> >
19 : public traits<MatrixType>
20 {};
21 
22 } // namespace internal
23 
24 template<typename MatrixType, int Mode> class SparseTriangularView
25   : public SparseMatrixBase<SparseTriangularView<MatrixType,Mode> >
26 {
27     enum { SkipFirst = ((Mode&Lower) && !(MatrixType::Flags&RowMajorBit))
28                     || ((Mode&Upper) &&  (MatrixType::Flags&RowMajorBit)),
29            SkipLast = !SkipFirst,
30            HasUnitDiag = (Mode&UnitDiag) ? 1 : 0
31     };
32 
33   public:
34 
35     EIGEN_SPARSE_PUBLIC_INTERFACE(SparseTriangularView)
36 
37     class InnerIterator;
38     class ReverseInnerIterator;
39 
40     inline Index rows() const { return m_matrix.rows(); }
41     inline Index cols() const { return m_matrix.cols(); }
42 
43     typedef typename MatrixType::Nested MatrixTypeNested;
44     typedef typename internal::remove_reference<MatrixTypeNested>::type MatrixTypeNestedNonRef;
45     typedef typename internal::remove_all<MatrixTypeNested>::type MatrixTypeNestedCleaned;
46 
47     inline SparseTriangularView(const MatrixType& matrix) : m_matrix(matrix) {}
48 
49     /** \internal */
50     inline const MatrixTypeNestedCleaned& nestedExpression() const { return m_matrix; }
51 
52     template<typename OtherDerived>
53     typename internal::plain_matrix_type_column_major<OtherDerived>::type
54     solve(const MatrixBase<OtherDerived>& other) const;
55 
56     template<typename OtherDerived> void solveInPlace(MatrixBase<OtherDerived>& other) const;
57     template<typename OtherDerived> void solveInPlace(SparseMatrixBase<OtherDerived>& other) const;
58 
59   protected:
60     MatrixTypeNested m_matrix;
61 };
62 
63 template<typename MatrixType, int Mode>
64 class SparseTriangularView<MatrixType,Mode>::InnerIterator : public MatrixTypeNestedCleaned::InnerIterator
65 {
66     typedef typename MatrixTypeNestedCleaned::InnerIterator Base;
67   public:
68 
69     EIGEN_STRONG_INLINE InnerIterator(const SparseTriangularView& view, Index outer)
70       : Base(view.nestedExpression(), outer), m_returnOne(false)
71     {
72       if(SkipFirst)
73       {
74         while((*this) && (HasUnitDiag ? this->index()<=outer : this->index()<outer))
75           Base::operator++();
76         if(HasUnitDiag)
77           m_returnOne = true;
78       }
79       else if(HasUnitDiag && ((!Base::operator bool()) || Base::index()>=Base::outer()))
80       {
81         if((!SkipFirst) && Base::operator bool())
82           Base::operator++();
83         m_returnOne = true;
84       }
85     }
86 
87     EIGEN_STRONG_INLINE InnerIterator& operator++()
88     {
89       if(HasUnitDiag && m_returnOne)
90         m_returnOne = false;
91       else
92       {
93         Base::operator++();
94         if(HasUnitDiag && (!SkipFirst) && ((!Base::operator bool()) || Base::index()>=Base::outer()))
95         {
96           if((!SkipFirst) && Base::operator bool())
97             Base::operator++();
98           m_returnOne = true;
99         }
100       }
101       return *this;
102     }
103 
104     inline Index row() const { return Base::row(); }
105     inline Index col() const { return Base::col(); }
106     inline Index index() const
107     {
108       if(HasUnitDiag && m_returnOne)  return Base::outer();
109       else                            return Base::index();
110     }
111     inline Scalar value() const
112     {
113       if(HasUnitDiag && m_returnOne)  return Scalar(1);
114       else                            return Base::value();
115     }
116 
117     EIGEN_STRONG_INLINE operator bool() const
118     {
119       if(HasUnitDiag && m_returnOne)
120         return true;
121       return (SkipFirst ? Base::operator bool() : (Base::operator bool() && this->index() <= this->outer()));
122     }
123   protected:
124     bool m_returnOne;
125 };
126 
127 template<typename MatrixType, int Mode>
128 class SparseTriangularView<MatrixType,Mode>::ReverseInnerIterator : public MatrixTypeNestedCleaned::ReverseInnerIterator
129 {
130     typedef typename MatrixTypeNestedCleaned::ReverseInnerIterator Base;
131   public:
132 
133     EIGEN_STRONG_INLINE ReverseInnerIterator(const SparseTriangularView& view, Index outer)
134       : Base(view.nestedExpression(), outer)
135     {
136       eigen_assert((!HasUnitDiag) && "ReverseInnerIterator does not support yet triangular views with a unit diagonal");
137       if(SkipLast)
138         while((*this) && this->index()>outer)
139           --(*this);
140     }
141 
142     EIGEN_STRONG_INLINE InnerIterator& operator--()
143     { Base::operator--(); return *this; }
144 
145     inline Index row() const { return Base::row(); }
146     inline Index col() const { return Base::col(); }
147 
148     EIGEN_STRONG_INLINE operator bool() const
149     {
150       return SkipLast ? Base::operator bool() : (Base::operator bool() && this->index() >= this->outer());
151     }
152 };
153 
154 template<typename Derived>
155 template<int Mode>
156 inline const SparseTriangularView<Derived, Mode>
157 SparseMatrixBase<Derived>::triangularView() const
158 {
159   return derived();
160 }
161 
162 } // end namespace Eigen
163 
164 #endif // EIGEN_SPARSE_TRIANGULARVIEW_H
165