1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud (at) inria.fr> 5 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1 (at) 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_VECTORBLOCK_H 12 #define EIGEN_VECTORBLOCK_H 13 14 namespace Eigen { 15 16 namespace internal { 17 template<typename VectorType, int Size> 18 struct traits<VectorBlock<VectorType, Size> > 19 : public traits<Block<VectorType, 20 traits<VectorType>::Flags & RowMajorBit ? 1 : Size, 21 traits<VectorType>::Flags & RowMajorBit ? Size : 1> > 22 { 23 }; 24 } 25 26 /** \class VectorBlock 27 * \ingroup Core_Module 28 * 29 * \brief Expression of a fixed-size or dynamic-size sub-vector 30 * 31 * \tparam VectorType the type of the object in which we are taking a sub-vector 32 * \tparam Size size of the sub-vector we are taking at compile time (optional) 33 * 34 * This class represents an expression of either a fixed-size or dynamic-size sub-vector. 35 * It is the return type of DenseBase::segment(Index,Index) and DenseBase::segment<int>(Index) and 36 * most of the time this is the only way it is used. 37 * 38 * However, if you want to directly maniputate sub-vector expressions, 39 * for instance if you want to write a function returning such an expression, you 40 * will need to use this class. 41 * 42 * Here is an example illustrating the dynamic case: 43 * \include class_VectorBlock.cpp 44 * Output: \verbinclude class_VectorBlock.out 45 * 46 * \note Even though this expression has dynamic size, in the case where \a VectorType 47 * has fixed size, this expression inherits a fixed maximal size which means that evaluating 48 * it does not cause a dynamic memory allocation. 49 * 50 * Here is an example illustrating the fixed-size case: 51 * \include class_FixedVectorBlock.cpp 52 * Output: \verbinclude class_FixedVectorBlock.out 53 * 54 * \sa class Block, DenseBase::segment(Index,Index,Index,Index), DenseBase::segment(Index,Index) 55 */ 56 template<typename VectorType, int Size> class VectorBlock 57 : public Block<VectorType, 58 internal::traits<VectorType>::Flags & RowMajorBit ? 1 : Size, 59 internal::traits<VectorType>::Flags & RowMajorBit ? Size : 1> 60 { 61 typedef Block<VectorType, 62 internal::traits<VectorType>::Flags & RowMajorBit ? 1 : Size, 63 internal::traits<VectorType>::Flags & RowMajorBit ? Size : 1> Base; 64 enum { 65 IsColVector = !(internal::traits<VectorType>::Flags & RowMajorBit) 66 }; 67 public: 68 EIGEN_DENSE_PUBLIC_INTERFACE(VectorBlock) 69 70 using Base::operator=; 71 72 /** Dynamic-size constructor 73 */ 74 EIGEN_DEVICE_FUNC 75 inline VectorBlock(VectorType& vector, Index start, Index size) 76 : Base(vector, 77 IsColVector ? start : 0, IsColVector ? 0 : start, 78 IsColVector ? size : 1, IsColVector ? 1 : size) 79 { 80 EIGEN_STATIC_ASSERT_VECTOR_ONLY(VectorBlock); 81 } 82 83 /** Fixed-size constructor 84 */ 85 EIGEN_DEVICE_FUNC 86 inline VectorBlock(VectorType& vector, Index start) 87 : Base(vector, IsColVector ? start : 0, IsColVector ? 0 : start) 88 { 89 EIGEN_STATIC_ASSERT_VECTOR_ONLY(VectorBlock); 90 } 91 }; 92 93 94 } // end namespace Eigen 95 96 #endif // EIGEN_VECTORBLOCK_H 97
