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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 Gael Guennebaud <gael.guennebaud@inria.fr>
5 // Copyright (C) 2006-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
6 //
7 // This Source Code Form is subject to the terms of the Mozilla
8 // Public License v. 2.0. If a copy of the MPL was not distributed
9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
10 
11 #ifndef EIGEN_BLOCK_H
12 #define EIGEN_BLOCK_H
13 
14 namespace Eigen {
15 
16 /** \class Block
17   * \ingroup Core_Module
18   *
19   * \brief Expression of a fixed-size or dynamic-size block
20   *
21   * \param XprType the type of the expression in which we are taking a block
22   * \param BlockRows the number of rows of the block we are taking at compile time (optional)
23   * \param BlockCols the number of columns of the block we are taking at compile time (optional)
24   *
25   * This class represents an expression of either a fixed-size or dynamic-size block. It is the return
26   * type of DenseBase::block(Index,Index,Index,Index) and DenseBase::block<int,int>(Index,Index) and
27   * most of the time this is the only way it is used.
28   *
29   * However, if you want to directly maniputate block expressions,
30   * for instance if you want to write a function returning such an expression, you
31   * will need to use this class.
32   *
33   * Here is an example illustrating the dynamic case:
34   * \include class_Block.cpp
35   * Output: \verbinclude class_Block.out
36   *
37   * \note Even though this expression has dynamic size, in the case where \a XprType
38   * has fixed size, this expression inherits a fixed maximal size which means that evaluating
39   * it does not cause a dynamic memory allocation.
40   *
41   * Here is an example illustrating the fixed-size case:
42   * \include class_FixedBlock.cpp
43   * Output: \verbinclude class_FixedBlock.out
44   *
45   * \sa DenseBase::block(Index,Index,Index,Index), DenseBase::block(Index,Index), class VectorBlock
46   */
47 
48 namespace internal {
49 template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
50 struct traits<Block<XprType, BlockRows, BlockCols, InnerPanel> > : traits<XprType>
51 {
52   typedef typename traits<XprType>::Scalar Scalar;
53   typedef typename traits<XprType>::StorageKind StorageKind;
54   typedef typename traits<XprType>::XprKind XprKind;
55   typedef typename nested<XprType>::type XprTypeNested;
56   typedef typename remove_reference<XprTypeNested>::type _XprTypeNested;
57   enum{
58     MatrixRows = traits<XprType>::RowsAtCompileTime,
59     MatrixCols = traits<XprType>::ColsAtCompileTime,
60     RowsAtCompileTime = MatrixRows == 0 ? 0 : BlockRows,
61     ColsAtCompileTime = MatrixCols == 0 ? 0 : BlockCols,
62     MaxRowsAtCompileTime = BlockRows==0 ? 0
63                          : RowsAtCompileTime != Dynamic ? int(RowsAtCompileTime)
64                          : int(traits<XprType>::MaxRowsAtCompileTime),
65     MaxColsAtCompileTime = BlockCols==0 ? 0
66                          : ColsAtCompileTime != Dynamic ? int(ColsAtCompileTime)
67                          : int(traits<XprType>::MaxColsAtCompileTime),
68     XprTypeIsRowMajor = (int(traits<XprType>::Flags)&RowMajorBit) != 0,
69     IsDense = is_same<StorageKind,Dense>::value,
70     IsRowMajor = (IsDense&&MaxRowsAtCompileTime==1&&MaxColsAtCompileTime!=1) ? 1
71                : (IsDense&&MaxColsAtCompileTime==1&&MaxRowsAtCompileTime!=1) ? 0
72                : XprTypeIsRowMajor,
73     HasSameStorageOrderAsXprType = (IsRowMajor == XprTypeIsRowMajor),
74     InnerSize = IsRowMajor ? int(ColsAtCompileTime) : int(RowsAtCompileTime),
75     InnerStrideAtCompileTime = HasSameStorageOrderAsXprType
76                              ? int(inner_stride_at_compile_time<XprType>::ret)
77                              : int(outer_stride_at_compile_time<XprType>::ret),
78     OuterStrideAtCompileTime = HasSameStorageOrderAsXprType
79                              ? int(outer_stride_at_compile_time<XprType>::ret)
80                              : int(inner_stride_at_compile_time<XprType>::ret),
81     MaskPacketAccessBit = (InnerSize == Dynamic || (InnerSize % packet_traits<Scalar>::size) == 0)
82                        && (InnerStrideAtCompileTime == 1)
83                         ? PacketAccessBit : 0,
84     MaskAlignedBit = (InnerPanel && (OuterStrideAtCompileTime!=Dynamic) && (((OuterStrideAtCompileTime * int(sizeof(Scalar))) % 16) == 0)) ? AlignedBit : 0,
85     FlagsLinearAccessBit = (RowsAtCompileTime == 1 || ColsAtCompileTime == 1 || (InnerPanel && (traits<XprType>::Flags&LinearAccessBit))) ? LinearAccessBit : 0,
86     FlagsLvalueBit = is_lvalue<XprType>::value ? LvalueBit : 0,
87     FlagsRowMajorBit = IsRowMajor ? RowMajorBit : 0,
88     Flags0 = traits<XprType>::Flags & ( (HereditaryBits & ~RowMajorBit) |
89                                         DirectAccessBit |
90                                         MaskPacketAccessBit |
91                                         MaskAlignedBit),
92     Flags = Flags0 | FlagsLinearAccessBit | FlagsLvalueBit | FlagsRowMajorBit
93   };
94 };
95 
96 template<typename XprType, int BlockRows=Dynamic, int BlockCols=Dynamic, bool InnerPanel = false,
97          bool HasDirectAccess = internal::has_direct_access<XprType>::ret> class BlockImpl_dense;
98 
99 } // end namespace internal
100 
101 template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, typename StorageKind> class BlockImpl;
102 
103 template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel> class Block
104   : public BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, typename internal::traits<XprType>::StorageKind>
105 {
106     typedef BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, typename internal::traits<XprType>::StorageKind> Impl;
107   public:
108     //typedef typename Impl::Base Base;
109     typedef Impl Base;
110     EIGEN_GENERIC_PUBLIC_INTERFACE(Block)
111     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Block)
112 
113     /** Column or Row constructor
114       */
115     inline Block(XprType& xpr, Index i) : Impl(xpr,i)
116     {
117       eigen_assert( (i>=0) && (
118           ((BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) && i<xpr.rows())
119         ||((BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) && i<xpr.cols())));
120     }
121 
122     /** Fixed-size constructor
123       */
124     inline Block(XprType& xpr, Index a_startRow, Index a_startCol)
125       : Impl(xpr, a_startRow, a_startCol)
126     {
127       EIGEN_STATIC_ASSERT(RowsAtCompileTime!=Dynamic && ColsAtCompileTime!=Dynamic,THIS_METHOD_IS_ONLY_FOR_FIXED_SIZE)
128       eigen_assert(a_startRow >= 0 && BlockRows >= 1 && a_startRow + BlockRows <= xpr.rows()
129              && a_startCol >= 0 && BlockCols >= 1 && a_startCol + BlockCols <= xpr.cols());
130     }
131 
132     /** Dynamic-size constructor
133       */
134     inline Block(XprType& xpr,
135           Index a_startRow, Index a_startCol,
136           Index blockRows, Index blockCols)
137       : Impl(xpr, a_startRow, a_startCol, blockRows, blockCols)
138     {
139       eigen_assert((RowsAtCompileTime==Dynamic || RowsAtCompileTime==blockRows)
140           && (ColsAtCompileTime==Dynamic || ColsAtCompileTime==blockCols));
141       eigen_assert(a_startRow >= 0 && blockRows >= 0 && a_startRow  <= xpr.rows() - blockRows
142           && a_startCol >= 0 && blockCols >= 0 && a_startCol <= xpr.cols() - blockCols);
143     }
144 };
145 
146 // The generic default implementation for dense block simplu forward to the internal::BlockImpl_dense
147 // that must be specialized for direct and non-direct access...
148 template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
149 class BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, Dense>
150   : public internal::BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel>
151 {
152     typedef internal::BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel> Impl;
153     typedef typename XprType::Index Index;
154   public:
155     typedef Impl Base;
156     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl)
157     inline BlockImpl(XprType& xpr, Index i) : Impl(xpr,i) {}
158     inline BlockImpl(XprType& xpr, Index a_startRow, Index a_startCol) : Impl(xpr, a_startRow, a_startCol) {}
159     inline BlockImpl(XprType& xpr, Index a_startRow, Index a_startCol, Index blockRows, Index blockCols)
160       : Impl(xpr, a_startRow, a_startCol, blockRows, blockCols) {}
161 };
162 
163 namespace internal {
164 
165 /** \internal Internal implementation of dense Blocks in the general case. */
166 template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, bool HasDirectAccess> class BlockImpl_dense
167   : public internal::dense_xpr_base<Block<XprType, BlockRows, BlockCols, InnerPanel> >::type
168 {
169     typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
170   public:
171 
172     typedef typename internal::dense_xpr_base<BlockType>::type Base;
173     EIGEN_DENSE_PUBLIC_INTERFACE(BlockType)
174     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl_dense)
175 
176     class InnerIterator;
177 
178     /** Column or Row constructor
179       */
180     inline BlockImpl_dense(XprType& xpr, Index i)
181       : m_xpr(xpr),
182         // It is a row if and only if BlockRows==1 and BlockCols==XprType::ColsAtCompileTime,
183         // and it is a column if and only if BlockRows==XprType::RowsAtCompileTime and BlockCols==1,
184         // all other cases are invalid.
185         // The case a 1x1 matrix seems ambiguous, but the result is the same anyway.
186         m_startRow( (BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) ? i : 0),
187         m_startCol( (BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) ? i : 0),
188         m_blockRows(BlockRows==1 ? 1 : xpr.rows()),
189         m_blockCols(BlockCols==1 ? 1 : xpr.cols())
190     {}
191 
192     /** Fixed-size constructor
193       */
194     inline BlockImpl_dense(XprType& xpr, Index a_startRow, Index a_startCol)
195       : m_xpr(xpr), m_startRow(a_startRow), m_startCol(a_startCol),
196                     m_blockRows(BlockRows), m_blockCols(BlockCols)
197     {}
198 
199     /** Dynamic-size constructor
200       */
201     inline BlockImpl_dense(XprType& xpr,
202           Index a_startRow, Index a_startCol,
203           Index blockRows, Index blockCols)
204       : m_xpr(xpr), m_startRow(a_startRow), m_startCol(a_startCol),
205                     m_blockRows(blockRows), m_blockCols(blockCols)
206     {}
207 
208     inline Index rows() const { return m_blockRows.value(); }
209     inline Index cols() const { return m_blockCols.value(); }
210 
211     inline Scalar& coeffRef(Index rowId, Index colId)
212     {
213       EIGEN_STATIC_ASSERT_LVALUE(XprType)
214       return m_xpr.const_cast_derived()
215                .coeffRef(rowId + m_startRow.value(), colId + m_startCol.value());
216     }
217 
218     inline const Scalar& coeffRef(Index rowId, Index colId) const
219     {
220       return m_xpr.derived()
221                .coeffRef(rowId + m_startRow.value(), colId + m_startCol.value());
222     }
223 
224     EIGEN_STRONG_INLINE const CoeffReturnType coeff(Index rowId, Index colId) const
225     {
226       return m_xpr.coeff(rowId + m_startRow.value(), colId + m_startCol.value());
227     }
228 
229     inline Scalar& coeffRef(Index index)
230     {
231       EIGEN_STATIC_ASSERT_LVALUE(XprType)
232       return m_xpr.const_cast_derived()
233              .coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
234                        m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
235     }
236 
237     inline const Scalar& coeffRef(Index index) const
238     {
239       return m_xpr.const_cast_derived()
240              .coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
241                        m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
242     }
243 
244     inline const CoeffReturnType coeff(Index index) const
245     {
246       return m_xpr
247              .coeff(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
248                     m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
249     }
250 
251     template<int LoadMode>
252     inline PacketScalar packet(Index rowId, Index colId) const
253     {
254       return m_xpr.template packet<Unaligned>
255               (rowId + m_startRow.value(), colId + m_startCol.value());
256     }
257 
258     template<int LoadMode>
259     inline void writePacket(Index rowId, Index colId, const PacketScalar& val)
260     {
261       m_xpr.const_cast_derived().template writePacket<Unaligned>
262               (rowId + m_startRow.value(), colId + m_startCol.value(), val);
263     }
264 
265     template<int LoadMode>
266     inline PacketScalar packet(Index index) const
267     {
268       return m_xpr.template packet<Unaligned>
269               (m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
270                m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
271     }
272 
273     template<int LoadMode>
274     inline void writePacket(Index index, const PacketScalar& val)
275     {
276       m_xpr.const_cast_derived().template writePacket<Unaligned>
277          (m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
278           m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0), val);
279     }
280 
281     #ifdef EIGEN_PARSED_BY_DOXYGEN
282     /** \sa MapBase::data() */
283     inline const Scalar* data() const;
284     inline Index innerStride() const;
285     inline Index outerStride() const;
286     #endif
287 
288     const typename internal::remove_all<typename XprType::Nested>::type& nestedExpression() const
289     {
290       return m_xpr;
291     }
292 
293     Index startRow() const
294     {
295       return m_startRow.value();
296     }
297 
298     Index startCol() const
299     {
300       return m_startCol.value();
301     }
302 
303   protected:
304 
305     const typename XprType::Nested m_xpr;
306     const internal::variable_if_dynamic<Index, XprType::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
307     const internal::variable_if_dynamic<Index, XprType::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
308     const internal::variable_if_dynamic<Index, RowsAtCompileTime> m_blockRows;
309     const internal::variable_if_dynamic<Index, ColsAtCompileTime> m_blockCols;
310 };
311 
312 /** \internal Internal implementation of dense Blocks in the direct access case.*/
313 template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
314 class BlockImpl_dense<XprType,BlockRows,BlockCols, InnerPanel,true>
315   : public MapBase<Block<XprType, BlockRows, BlockCols, InnerPanel> >
316 {
317     typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
318   public:
319 
320     typedef MapBase<BlockType> Base;
321     EIGEN_DENSE_PUBLIC_INTERFACE(BlockType)
322     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl_dense)
323 
324     /** Column or Row constructor
325       */
326     inline BlockImpl_dense(XprType& xpr, Index i)
327       : Base(internal::const_cast_ptr(&xpr.coeffRef(
328               (BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) ? i : 0,
329               (BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) ? i : 0)),
330              BlockRows==1 ? 1 : xpr.rows(),
331              BlockCols==1 ? 1 : xpr.cols()),
332         m_xpr(xpr)
333     {
334       init();
335     }
336 
337     /** Fixed-size constructor
338       */
339     inline BlockImpl_dense(XprType& xpr, Index startRow, Index startCol)
340       : Base(internal::const_cast_ptr(&xpr.coeffRef(startRow,startCol))), m_xpr(xpr)
341     {
342       init();
343     }
344 
345     /** Dynamic-size constructor
346       */
347     inline BlockImpl_dense(XprType& xpr,
348           Index startRow, Index startCol,
349           Index blockRows, Index blockCols)
350       : Base(internal::const_cast_ptr(&xpr.coeffRef(startRow,startCol)), blockRows, blockCols),
351         m_xpr(xpr)
352     {
353       init();
354     }
355 
356     const typename internal::remove_all<typename XprType::Nested>::type& nestedExpression() const
357     {
358       return m_xpr;
359     }
360 
361     /** \sa MapBase::innerStride() */
362     inline Index innerStride() const
363     {
364       return internal::traits<BlockType>::HasSameStorageOrderAsXprType
365              ? m_xpr.innerStride()
366              : m_xpr.outerStride();
367     }
368 
369     /** \sa MapBase::outerStride() */
370     inline Index outerStride() const
371     {
372       return m_outerStride;
373     }
374 
375   #ifndef __SUNPRO_CC
376   // FIXME sunstudio is not friendly with the above friend...
377   // META-FIXME there is no 'friend' keyword around here. Is this obsolete?
378   protected:
379   #endif
380 
381     #ifndef EIGEN_PARSED_BY_DOXYGEN
382     /** \internal used by allowAligned() */
383     inline BlockImpl_dense(XprType& xpr, const Scalar* data, Index blockRows, Index blockCols)
384       : Base(data, blockRows, blockCols), m_xpr(xpr)
385     {
386       init();
387     }
388     #endif
389 
390   protected:
391     void init()
392     {
393       m_outerStride = internal::traits<BlockType>::HasSameStorageOrderAsXprType
394                     ? m_xpr.outerStride()
395                     : m_xpr.innerStride();
396     }
397 
398     typename XprType::Nested m_xpr;
399     Index m_outerStride;
400 };
401 
402 } // end namespace internal
403 
404 } // end namespace Eigen
405 
406 #endif // EIGEN_BLOCK_H
407