1 | // This file is part of Eigen, a lightweight C++ template library
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2 | // for linear algebra.
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3 | //
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4 | // Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
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5 | // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
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6 | //
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7 | // This Source Code Form is subject to the terms of the Mozilla
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8 | // Public License v. 2.0. If a copy of the MPL was not distributed
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9 | // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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10 |
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11 | #ifndef EIGEN_VECTORBLOCK_H
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12 | #define EIGEN_VECTORBLOCK_H
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13 |
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14 | namespace Eigen {
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15 |
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16 | /** \class VectorBlock
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17 | * \ingroup Core_Module
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18 | *
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19 | * \brief Expression of a fixed-size or dynamic-size sub-vector
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20 | *
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21 | * \param VectorType the type of the object in which we are taking a sub-vector
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22 | * \param Size size of the sub-vector we are taking at compile time (optional)
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23 | *
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24 | * This class represents an expression of either a fixed-size or dynamic-size sub-vector.
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25 | * It is the return type of DenseBase::segment(Index,Index) and DenseBase::segment<int>(Index) and
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26 | * most of the time this is the only way it is used.
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27 | *
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28 | * However, if you want to directly maniputate sub-vector expressions,
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29 | * for instance if you want to write a function returning such an expression, you
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30 | * will need to use this class.
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31 | *
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32 | * Here is an example illustrating the dynamic case:
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33 | * \include class_VectorBlock.cpp
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34 | * Output: \verbinclude class_VectorBlock.out
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35 | *
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36 | * \note Even though this expression has dynamic size, in the case where \a VectorType
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37 | * has fixed size, this expression inherits a fixed maximal size which means that evaluating
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38 | * it does not cause a dynamic memory allocation.
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39 | *
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40 | * Here is an example illustrating the fixed-size case:
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41 | * \include class_FixedVectorBlock.cpp
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42 | * Output: \verbinclude class_FixedVectorBlock.out
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43 | *
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44 | * \sa class Block, DenseBase::segment(Index,Index,Index,Index), DenseBase::segment(Index,Index)
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45 | */
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46 |
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47 | namespace internal {
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48 | template<typename VectorType, int Size>
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49 | struct traits<VectorBlock<VectorType, Size> >
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50 | : public traits<Block<VectorType,
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51 | traits<VectorType>::Flags & RowMajorBit ? 1 : Size,
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52 | traits<VectorType>::Flags & RowMajorBit ? Size : 1> >
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53 | {
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54 | };
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55 | }
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56 |
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57 | template<typename VectorType, int Size> class VectorBlock
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58 | : public Block<VectorType,
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59 | internal::traits<VectorType>::Flags & RowMajorBit ? 1 : Size,
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60 | internal::traits<VectorType>::Flags & RowMajorBit ? Size : 1>
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61 | {
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62 | typedef Block<VectorType,
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63 | internal::traits<VectorType>::Flags & RowMajorBit ? 1 : Size,
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64 | internal::traits<VectorType>::Flags & RowMajorBit ? Size : 1> Base;
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65 | enum {
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66 | IsColVector = !(internal::traits<VectorType>::Flags & RowMajorBit)
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67 | };
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68 | public:
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69 | EIGEN_DENSE_PUBLIC_INTERFACE(VectorBlock)
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70 |
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71 | using Base::operator=;
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72 |
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73 | /** Dynamic-size constructor
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74 | */
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75 | inline VectorBlock(VectorType& vector, Index start, Index size)
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76 | : Base(vector,
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77 | IsColVector ? start : 0, IsColVector ? 0 : start,
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78 | IsColVector ? size : 1, IsColVector ? 1 : size)
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79 | {
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80 | EIGEN_STATIC_ASSERT_VECTOR_ONLY(VectorBlock);
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81 | }
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82 |
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83 | /** Fixed-size constructor
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84 | */
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85 | inline VectorBlock(VectorType& vector, Index start)
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86 | : Base(vector, IsColVector ? start : 0, IsColVector ? 0 : start)
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87 | {
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88 | EIGEN_STATIC_ASSERT_VECTOR_ONLY(VectorBlock);
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89 | }
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90 | };
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91 |
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92 |
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93 | } // end namespace Eigen
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94 |
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95 | #endif // EIGEN_VECTORBLOCK_H
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