cart-elc

Source code for CART-ELC
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Stride.h (4212B)

      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@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   * Both strides can be negative, however, a negative stride of -1 cannot be specified at compiletime
     42   * because of the ambiguity with Dynamic which is defined to -1 (historically, negative strides were
     43   * not allowed).
     44   *
     45   * \sa class InnerStride, class OuterStride, \ref TopicStorageOrders
     46   */
     47 template<int _OuterStrideAtCompileTime, int _InnerStrideAtCompileTime>
     48 class Stride
     49 {
     50   public:
     51     typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
     52     enum {
     53       InnerStrideAtCompileTime = _InnerStrideAtCompileTime,
     54       OuterStrideAtCompileTime = _OuterStrideAtCompileTime
     55     };
     56 
     57     /** Default constructor, for use when strides are fixed at compile time */
     58     EIGEN_DEVICE_FUNC
     59     Stride()
     60       : m_outer(OuterStrideAtCompileTime), m_inner(InnerStrideAtCompileTime)
     61     {
     62       // FIXME: for Eigen 4 we should use DynamicIndex instead of Dynamic.
     63       // FIXME: for Eigen 4 we should also unify this API with fix<>
     64       eigen_assert(InnerStrideAtCompileTime != Dynamic && OuterStrideAtCompileTime != Dynamic);
     65     }
     66 
     67     /** Constructor allowing to pass the strides at runtime */
     68     EIGEN_DEVICE_FUNC
     69     Stride(Index outerStride, Index innerStride)
     70       : m_outer(outerStride), m_inner(innerStride)
     71     {
     72     }
     73 
     74     /** Copy constructor */
     75     EIGEN_DEVICE_FUNC
     76     Stride(const Stride& other)
     77       : m_outer(other.outer()), m_inner(other.inner())
     78     {}
     79 
     80     /** \returns the outer stride */
     81     EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR
     82     inline Index outer() const { return m_outer.value(); }
     83     /** \returns the inner stride */
     84     EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR
     85     inline Index inner() const { return m_inner.value(); }
     86 
     87   protected:
     88     internal::variable_if_dynamic<Index, OuterStrideAtCompileTime> m_outer;
     89     internal::variable_if_dynamic<Index, InnerStrideAtCompileTime> m_inner;
     90 };
     91 
     92 /** \brief Convenience specialization of Stride to specify only an inner stride
     93   * See class Map for some examples */
     94 template<int Value>
     95 class InnerStride : public Stride<0, Value>
     96 {
     97     typedef Stride<0, Value> Base;
     98   public:
     99     EIGEN_DEVICE_FUNC InnerStride() : Base() {}
    100     EIGEN_DEVICE_FUNC InnerStride(Index v) : Base(0, v) {} // FIXME making this explicit could break valid code
    101 };
    102 
    103 /** \brief Convenience specialization of Stride to specify only an outer stride
    104   * See class Map for some examples */
    105 template<int Value>
    106 class OuterStride : public Stride<Value, 0>
    107 {
    108     typedef Stride<Value, 0> Base;
    109   public:
    110     EIGEN_DEVICE_FUNC OuterStride() : Base() {}
    111     EIGEN_DEVICE_FUNC OuterStride(Index v) : Base(v,0) {} // FIXME making this explicit could break valid code
    112 };
    113 
    114 } // end namespace Eigen
    115 
    116 #endif // EIGEN_STRIDE_H