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gslice Class Reference

List of all members.

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Detailed Description

Generalized slice.

Represents a generalized slice out of an array. It specifies a starting index, a set of lengths and a set of strides; the number of lengths shall equal the number of strides. The gslice is useful for building multidimensional arrays out of the one-dimensional stdext::valarray. Used by stdext::term to construct a stdext::impl::gslice_term.

In order to step through each element selected by a gslice:

• Suppose size and stride have n elements.
• Make index with n elements, all set to 0.
• Increment the last index. Each index [i] may range from 0 to size [i] - 1, and if incrementing index [i] would exceed that range, set to 0 and increment index [i - 1] instead.
• The actual address is start + sum of index [i] * stride [i] for all i.

An example that appears in the Standard:

• Suppose start = 3, length = {2, 4, 3}, stride = {19, 4, 1}.
• Make index with 3 elements.
• Increment the last index. This yields {0, 0, 0}, {0, 0, 1}, {0, 0, 2}, {0, 1, 0}, {0, 1, 1}, {0, 1, 2}, {0, 2, 0}, {0, 2, 1}, {0, 2, 2}, {0, 3, 0}, {0, 3, 1}, {0, 3, 2}, {1, 0, 0}, {1, 0, 1} ... The actual addresses are then: 3, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 17, 22, 23 ...

Header:

#include <macstl/valarray.h>

Public Member Functions
	gslice (std::size_t start, const valarray< std::size_t > &length, const valarray< std::size_t > &stride)
	Constructs a gslice with start, a set of length and a set of stride.
	gslice ()
	Constructs a degenerate slice.
impl::array_term< std::size_t >	size () const
	Gets the lengths of the gslice.
std::size_t	start () const
	Gets the start index of the gslice.
impl::array_term< std::size_t >	stride () const
	Gets the strides of the gslice.

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