pni::core::slice Class Reference

index slice More...

#include <slice.hpp>

Public Member Functions
	slice ()
	default constructor
	slice (size_t first, size_t last, size_t stride=1)
	standard constructor More...
	slice (const std::initializer_list< size_t > &l)
	construction from a initializer list More...
	slice (size_t index)
	construction from a single index More...
	~slice ()
	destructor
slice &	operator= (const slice &s)
	copy assignment operator
size_t	first () const
	return the first element More...
size_t	last () const
	return last element More...
size_t	stride () const
	return stride More...

Private Member Functions
void	_check_start_stop (const exception_record &o) const
	check first and last index More...
void	_check_stride (const exception_record &o) const
	check stride More...

Private Attributes
size_t	_first
	first index in the slice
size_t	_last
	last index in the slice
size_t	_stride
	distance between indices

Detailed Description

This types represents an index slice for an array. A slice can be used to identify an index range along a single dimensions. slice objects are of particular importance for creating array_view from mdarray instancers.

A slice includes all indices between the the first and last index of the slice where the last index is not included. A stride can be passed during construction which determines the number of steps between each subsequent element. If the stride is not 1 the last index will be adopted so that the

Examples:

example_array3.cpp, and example_array4.cpp.

Constructor & Destructor Documentation

pni::core::slice::slice ( size_t  first, size_t  last, size_t  stride = 1  )

explicit

This is the default constructor for a Slice object.

Exceptions

range_error

if the first index exceeds the last

Parameters

first	first index
last	index
stride	steps between subsequent elements

pni::core::slice::slice ( const std::initializer_list< size_t > &  l )

explicit

This can be used for implicit conversion which is sometimes quite useful for the creation fo array views.

mdarray<...>  a({10,100});

//default construction of a view
auto v1 = a(slice(1,4),slice(50,100));

//one can also use initializer lists
auto v2 = a({1,4},{50,100});

! If the initializer list has only two elements they are treated as first and last element of the slice and the stride is set to 1. In the case of a three element initializer list the last element is considered as the stride of the slice.

Exceptions

range_error

if the first element is larger than the last

Parameters

l	initializer list

pni::core::slice::slice ( size_t  index )

explicit

Constructor uses a single index. This constructor is equivalent to use slice(index,index+1,1).

Parameters

index

single index from which to create the slice

Member Function Documentation

void pni::core::slice::_check_start_stop ( const exception_record &  o ) const

private

This private method throws an exception if the first index of the range exceeds the last one.

Exceptions

range_error

if first > last

Parameters

o	signature of the origin where the error occured

void pni::core::slice::_check_stride ( const exception_record &  o ) const

private

Checks if the stride does not exceed the span of the slice. If it does an exception will be thrown.

Exceptions

range_error

if stride exceeds span

Parameters

o	signature of the origin where the error occured

size_t pni::core::slice::first ( ) const

inline

Returns

first element of slice

size_t pni::core::slice::last ( ) const

inline

Returns

last element of slice

size_t pni::core::slice::stride ( ) const

inline

Returns

stride of the slice

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

• slice.hpp