iolink::Indexer Class Reference

This class is used to index a classic array into a multi dimensional array. More...

#include <iolink/Indexer.h>

Public Member Functions
	Indexer (const VectorXu64 &shape, const VectorXu64 &stride, const VectorXu64 &layout)
	Create an indexer by giving all its informations.
	Indexer (const VectorXu64 &shape, const VectorXu64 &stride, MemoryLayout standardLayout)
	Create an indexer by giving all its informations.
	Indexer (const VectorXu64 &shape, const VectorXu64 &layout)
	Initialize the indexer using a custom memory layout.
	Indexer (const VectorXu64 &shape, MemoryLayout standardLayout)
	Auto compute the Indexer's strides from shape and standard layout.
	Indexer (const VectorXu64 &shape)
	Simpliest way to initialize an indexer from a shape.
	Indexer (const VectorXu64 &shape, DataType dtype)
	Constructor with shape and datatype, using default layout and stride.
	Indexer (const VectorXu64 &shape, DataType dtype, MemoryLayout standardLayout)
	Constructor with shape, datatype and standard layout, using default stride.
	Indexer (const VectorXu64 &shape, DataType dtype, const VectorXu64 &byteStride)
	Constructor with shape, datatype and byte stride, using default layout.
	Indexer (const VectorXu64 &shape, DataType dtype, const VectorXu64 &byteStride, const VectorXu64 &layout)
	Constructor with shape, datatype, byte stride and layout.
	Indexer (const Indexer &other)
Indexer &	operator= (const Indexer &other)
	Indexer (Indexer &&other) noexcept
Indexer &	operator= (Indexer &&other) noexcept
bool	operator== (const Indexer &other) const
bool	operator!= (const Indexer &other) const
size_t	dimensionCount () const
	The number of dimensions managed by this indexer.
const VectorXu64 &	shape () const
	Return the shape.
DataType	dtype () const
const VectorXu64 &	stride () const
	Return the stride.
const VectorXu64 &	byteStride () const
const VectorXu64 &	layout () const
	Return the layout dimension order.
size_t	shape (size_t index) const
	Return the current size for given dimension.
size_t	stride (size_t index) const
	Return the current stride for given dimension.
size_t	byteStride (size_t index) const
size_t	layout (size_t index) const
	Return the dimension index of the nth one in order.
size_t	elementCount () const
	Returns the number of elements managed by this Indexer.
size_t	byteCount () const
	Get the total number of bytes needed to adress this indexer, taking the padding into account.
size_t	offset (const VectorXu64 &index) const
	Return the computed 1D offset corresponding to indexed sample in multi dimensional array.
size_t	byteOffset (const VectorXu64 &index) const
	Computes the offset in bytes to the given index.
bool	isContinuous () const
	Checks if the indexed elements are contiguous.

Detailed Description

This class is used to index a classic array into a multi dimensional array.

Its main use is to convert a multi-dimensional index into the corresponding offset in the flat array used for storage. An indexer contains all the needed tools and describes how the data is really stored. The three main elements are: the shape, the stride, and the layout.

The shape is simply the size of the indexed array in each dimension, for example an array with two columns and two rows will have a shape of {2, 2}.

The stride contains the offset between each iteration of a dimension, in elements. For example, our {2, 2} array will usually have a stride of {1, 2}, as each column element is adjacent (hence the stride of one), and when iterating element on a line, you must skip one element on the underlying array (hence the stride of 2). The stride dimension are in the same order as the shape, but they do not have to be in ascendent order. Actually, reverse order arrays (C convention) will have inversed strides, for example, {2, 1} in our {2, 2} array case.

The layout describes in wich order each dimension is ordered internally, and can be used to enhance performance. The usual IOLink layout is {0, 1, ..., n - 1, n}. As we use the Fortran convention in IOLink, indexing a C array would use an inverted layout {n, n-1, ..., 1, 0}. This field enables user to easily know how data is organised without analysing the strides directly.

Constructor & Destructor Documentation

Indexer() [1/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		const VectorXu64 &	stride,
		const VectorXu64 &	layout
	)

Create an indexer by giving all its informations.

Here all the arguments are given, and are not checked, so if they are not consistant, they will give an undefined behavior.

Parameters

shape	The shape of the array to index.
stride	The stride of each dimension, the offset in elements between each increment in this dimension.
layout	The internal order of dimensions, {0, 1} is row-major and {1, 0} is col-major for example.

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use a constructor that specify the data type instead.

Indexer() [2/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		const VectorXu64 &	stride,
		MemoryLayout	standardLayout
	)

Create an indexer by giving all its informations.

Here all the arguments are given, and are not checked, so if they are not consistant, they will give an undefined behavior.

Parameters

shape	The shape of the array to index.
stride	The stride of each dimension, the offset in elements between each increment in this dimension.
standardLayout	A standard layout for the array.

Exceptions

Error

When the layout is unsupported

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use a constructor that specify the data type instead.

Indexer() [3/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		const VectorXu64 &	layout
	)

Initialize the indexer using a custom memory layout.

Parameters

shape	The shape of the indexed array
layout	The internal order of dimensions, {0, 1} is row-major and {1, 0} is col-major for example.

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use a constructor that specify the data type instead.

Indexer() [4/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		MemoryLayout	standardLayout
	)

Auto compute the Indexer's strides from shape and standard layout.

Parameters

shape	The narray sizes in each dimension
standardLayout	A standard layout for the array.

Exceptions

Error

When the layout is unsupported

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use a constructor that specify the data type instead.

Indexer() [5/9]

iolink::Indexer::Indexer ( const VectorXu64 &  shape )

explicit

Simpliest way to initialize an indexer from a shape.

The layout here is Fortran one, and the strides are computed according to it.

Parameters

shape

The desired shape of the multi dimensional array.

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use a constructor that specify the data type instead.

Indexer() [6/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		DataType	dtype
	)

Constructor with shape and datatype, using default layout and stride.

The default byte stride being computed from the shape and data type. The default layout being the Fortran array layout.

Parameters

shape	The shape of the indexed array.
dtype	The data type of the indexed array.

Indexer() [7/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		DataType	dtype,
		MemoryLayout	standardLayout
	)

Constructor with shape, datatype and standard layout, using default stride.

The default byte stride being computed from the shape, datatype, and standard layout.

Parameters

shape	The shape of the indexed array.
dtype	The data type of the indexed array.
standardLayout	A standard layout for the array.

Indexer() [8/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		DataType	dtype,
		const VectorXu64 &	byteStride
	)

Constructor with shape, datatype and byte stride, using default layout.

The default layout being the Fortran array layout.

Parameters

shape	The shape of the indexed array.
dtype	The data type of the indexed array.
byteStride	The stride in bytes of the indexed array.

Indexer() [9/9]

iolink::Indexer::Indexer	(	const VectorXu64 &	shape,
		DataType	dtype,
		const VectorXu64 &	byteStride,
		const VectorXu64 &	layout
	)

Constructor with shape, datatype, byte stride and layout.

Parameters

shape	The shape of the indexed array.
dtype	The data type of the indexed array.
byteStride	The stride in bytes of the indexed array.
layout	The layout of the indexed array.

Member Function Documentation

byteCount()

size_t iolink::Indexer::byteCount

(

)

const

Get the total number of bytes needed to adress this indexer, taking the padding into account.

Returns

the number of bytes managed by this Indexer.

byteOffset()

size_t iolink::Indexer::byteOffset

(

const VectorXu64 &

index

)

const

Computes the offset in bytes to the given index.

Parameters

index

The index of the element for which the offset must be computed.

Returns

the offset in bytes to the given index.

Exceptions

InvalidArgument

If the index is invalid.

byteStride() [1/2]

const VectorXu64 & iolink::Indexer::byteStride

(

)

const

Returns

the stride in bytes of this Indexer.

byteStride() [2/2]

size_t iolink::Indexer::byteStride

(

size_t

index

)

const

Returns

the stride in bytes for the given dimension.

dtype()

DataType iolink::Indexer::dtype

(

)

const

Returns

the data type of this Indexer.

isContinuous()

bool iolink::Indexer::isContinuous

(

)

const

Checks if the indexed elements are contiguous.

Elements are considered contiguous if they follow each other without any padding.

Returns

true if the indexed elements are continuous, false otherwise.

layout()

size_t iolink::Indexer::layout

(

size_t

index

)

const

Return the dimension index of the nth one in order.

Parameters

index

Index of the order dimension index.

offset()

size_t iolink::Indexer::offset

(

const VectorXu64 &

index

)

const

Return the computed 1D offset corresponding to indexed sample in multi dimensional array.

Parameters

index

The element's position for which offset must be computed.

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use the byteOffset method instead.

shape()

size_t iolink::Indexer::shape

(

size_t

index

)

const

Return the current size for given dimension.

Parameters

index

Index of the dimension to consider

stride() [1/2]

const VectorXu64 & iolink::Indexer::stride

(

)

const

Return the stride.

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use the byteStride method instead.

stride() [2/2]

size_t iolink::Indexer::stride

(

size_t

index

)

const

Return the current stride for given dimension.

Parameters

index

Index of the dimension to consider

Deprecated:

Deprecated in 1.8, will be dropped in 2.0, you should use the byteStride method instead.

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The documentation for this class was generated from the following file:

• iolink/public/include/iolink/Indexer.h