1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2010 Benoit Jacob <jacob.benoit.1 (at) gmail.com> 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_STRIDE_H 11 #define EIGEN_STRIDE_H 12 13 namespace Eigen { 14 15 /** \class Stride 16 * \ingroup Core_Module 17 * 18 * \brief Holds strides information for Map 19 * 20 * This class holds the strides information for mapping arrays with strides with class Map. 21 * 22 * It holds two values: the inner stride and the outer stride. 23 * 24 * The inner stride is the pointer increment between two consecutive entries within a given row of a 25 * row-major matrix or within a given column of a column-major matrix. 26 * 27 * The outer stride is the pointer increment between two consecutive rows of a row-major matrix or 28 * between two consecutive columns of a column-major matrix. 29 * 30 * These two values can be passed either at compile-time as template parameters, or at runtime as 31 * arguments to the constructor. 32 * 33 * Indeed, this class takes two template parameters: 34 * \tparam _OuterStrideAtCompileTime the outer stride, or Dynamic if you want to specify it at runtime. 35 * \tparam _InnerStrideAtCompileTime the inner stride, or Dynamic if you want to specify it at runtime. 36 * 37 * Here is an example: 38 * \include Map_general_stride.cpp 39 * Output: \verbinclude Map_general_stride.out 40 * 41 * \sa class InnerStride, class OuterStride, \ref TopicStorageOrders 42 */ 43 template<int _OuterStrideAtCompileTime, int _InnerStrideAtCompileTime> 44 class Stride 45 { 46 public: 47 typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3 48 enum { 49 InnerStrideAtCompileTime = _InnerStrideAtCompileTime, 50 OuterStrideAtCompileTime = _OuterStrideAtCompileTime 51 }; 52 53 /** Default constructor, for use when strides are fixed at compile time */ 54 EIGEN_DEVICE_FUNC 55 Stride() 56 : m_outer(OuterStrideAtCompileTime), m_inner(InnerStrideAtCompileTime) 57 { 58 eigen_assert(InnerStrideAtCompileTime != Dynamic && OuterStrideAtCompileTime != Dynamic); 59 } 60 61 /** Constructor allowing to pass the strides at runtime */ 62 EIGEN_DEVICE_FUNC 63 Stride(Index outerStride, Index innerStride) 64 : m_outer(outerStride), m_inner(innerStride) 65 { 66 eigen_assert(innerStride>=0 && outerStride>=0); 67 } 68 69 /** Copy constructor */ 70 EIGEN_DEVICE_FUNC 71 Stride(const Stride& other) 72 : m_outer(other.outer()), m_inner(other.inner()) 73 {} 74 75 /** \returns the outer stride */ 76 EIGEN_DEVICE_FUNC 77 inline Index outer() const { return m_outer.value(); } 78 /** \returns the inner stride */ 79 EIGEN_DEVICE_FUNC 80 inline Index inner() const { return m_inner.value(); } 81 82 protected: 83 internal::variable_if_dynamic<Index, OuterStrideAtCompileTime> m_outer; 84 internal::variable_if_dynamic<Index, InnerStrideAtCompileTime> m_inner; 85 }; 86 87 /** \brief Convenience specialization of Stride to specify only an inner stride 88 * See class Map for some examples */ 89 template<int Value> 90 class InnerStride : public Stride<0, Value> 91 { 92 typedef Stride<0, Value> Base; 93 public: 94 EIGEN_DEVICE_FUNC InnerStride() : Base() {} 95 EIGEN_DEVICE_FUNC InnerStride(Index v) : Base(0, v) {} // FIXME making this explicit could break valid code 96 }; 97 98 /** \brief Convenience specialization of Stride to specify only an outer stride 99 * See class Map for some examples */ 100 template<int Value> 101 class OuterStride : public Stride<Value, 0> 102 { 103 typedef Stride<Value, 0> Base; 104 public: 105 EIGEN_DEVICE_FUNC OuterStride() : Base() {} 106 EIGEN_DEVICE_FUNC OuterStride(Index v) : Base(v,0) {} // FIXME making this explicit could break valid code 107 }; 108 109 } // end namespace Eigen 110 111 #endif // EIGEN_STRIDE_H 112
