109 lines
3.5 KiB
C++
109 lines
3.5 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2010 Benoit Jacob <jacob.benoit.1@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#ifndef EIGEN_STRIDE_H
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#define EIGEN_STRIDE_H
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namespace Eigen {
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/** \class Stride
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* \ingroup Core_Module
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*
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* \brief Holds strides information for Map
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*
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* This class holds the strides information for mapping arrays with strides with class Map.
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*
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* It holds two values: the inner stride and the outer stride.
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*
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* The inner stride is the pointer increment between two consecutive entries within a given row of a
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* row-major matrix or within a given column of a column-major matrix.
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*
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* The outer stride is the pointer increment between two consecutive rows of a row-major matrix or
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* between two consecutive columns of a column-major matrix.
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*
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* These two values can be passed either at compile-time as template parameters, or at runtime as
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* arguments to the constructor.
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*
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* Indeed, this class takes two template parameters:
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* \param _OuterStrideAtCompileTime the outer stride, or Dynamic if you want to specify it at runtime.
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* \param _InnerStrideAtCompileTime the inner stride, or Dynamic if you want to specify it at runtime.
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*
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* Here is an example:
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* \include Map_general_stride.cpp
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* Output: \verbinclude Map_general_stride.out
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*
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* \sa class InnerStride, class OuterStride, \ref TopicStorageOrders
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*/
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template<int _OuterStrideAtCompileTime, int _InnerStrideAtCompileTime>
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class Stride
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{
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public:
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typedef DenseIndex Index;
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enum {
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InnerStrideAtCompileTime = _InnerStrideAtCompileTime,
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OuterStrideAtCompileTime = _OuterStrideAtCompileTime
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};
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/** Default constructor, for use when strides are fixed at compile time */
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Stride()
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: m_outer(OuterStrideAtCompileTime), m_inner(InnerStrideAtCompileTime)
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{
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eigen_assert(InnerStrideAtCompileTime != Dynamic && OuterStrideAtCompileTime != Dynamic);
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}
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/** Constructor allowing to pass the strides at runtime */
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Stride(Index outerStride, Index innerStride)
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: m_outer(outerStride), m_inner(innerStride)
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{
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eigen_assert(innerStride>=0 && outerStride>=0);
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}
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/** Copy constructor */
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Stride(const Stride& other)
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: m_outer(other.outer()), m_inner(other.inner())
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{}
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/** \returns the outer stride */
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inline Index outer() const { return m_outer.value(); }
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/** \returns the inner stride */
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inline Index inner() const { return m_inner.value(); }
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protected:
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internal::variable_if_dynamic<Index, OuterStrideAtCompileTime> m_outer;
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internal::variable_if_dynamic<Index, InnerStrideAtCompileTime> m_inner;
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};
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/** \brief Convenience specialization of Stride to specify only an inner stride
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* See class Map for some examples */
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template<int Value = Dynamic>
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class InnerStride : public Stride<0, Value>
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{
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typedef Stride<0, Value> Base;
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public:
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typedef DenseIndex Index;
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InnerStride() : Base() {}
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InnerStride(Index v) : Base(0, v) {}
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};
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/** \brief Convenience specialization of Stride to specify only an outer stride
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* See class Map for some examples */
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template<int Value = Dynamic>
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class OuterStride : public Stride<Value, 0>
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{
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typedef Stride<Value, 0> Base;
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public:
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typedef DenseIndex Index;
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OuterStride() : Base() {}
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OuterStride(Index v) : Base(v,0) {}
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};
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} // end namespace Eigen
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#endif // EIGEN_STRIDE_H
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