h5::array_interface::hyperslab

#include <h5/array_interface.hpp>

Detailed Description

Struct representing an HDF5 hyperslab.

A hyperslab is used to select elements from an n-dimensional array/dataspace and it is defined by 4 arrays of the same size as the rank of the underlying dataspace:

• offset: Origin of the hyperslab in the dataspace.
• stride: The number of elements to skip between each element or block to be selected. If the stride parameter is set to NULL, the stride size defaults to 1 in each dimension.
• count: The number of elements or blocks to select along each dimension.
• block: The size of a block selected from the dataspace. If the block parameter is set to NULL, the block size defaults to a single element in each dimension, as if the block array was set to all ones.

The imaginary part of a complex array/dataspace is treated as just another dimension, i.e. its rank is increased by one.

The following example selects every second column in a 7x7 dataspace:

h5::array_interface::hyperslab slab;
slab.offset = {0, 0};
slab.stride = {1, 2};
slab.count = {7, 4};
slab.block = {1, 1};

For a complex valued dataspace, the same example would look like this:

h5::array_interface::hyperslab slab;
slab.offset = {0, 0, 0};
slab.stride = {1, 2, 1};
slab.count = {7, 4, 2};
slab.block = {1, 1, 1};

Definition at line 90 of file array_interface.hpp.

Public Member Functions
	hyperslab ()=default
	Default constructor leaves the hyperslab empty (uninitialized).
	hyperslab (int rank, bool has_cplx_trailing_dim)
	Construct a new empty hyperslab for a dataspace of a given rank.
bool	empty () const
	Check whether the hyperslab is empty (has been initialized).
int	rank () const
	Get the rank of the hyperslab (including the possible added imaginary dimension).
v_t	shape () const
	Get the shape of the selected hyperslab.
auto	size () const
	Get the total number of elements in the hyperslab.

Public Attributes
v_t	block
	Shape of a single block selected from the dataspace.
v_t	count
	Number of elements or blocks to select along each dimension.
v_t	offset
	Index offset for each dimension.
v_t	stride
	Stride in each dimension (in the HDF5 sense).

Constructor & Destructor Documentation

hyperslab()

h5::array_interface::hyperslab::hyperslab ( int rank, bool has_cplx_trailing_dim )

inline

Construct a new empty hyperslab for a dataspace of a given rank.

If has_cplx_trailing_dim is true, the hyperslab gets an extra trailing dimension of size 2 to encode the imaginary part (TRIQS trailing-2 FLOAT convention for complex data). By default, offset and count are set to zero and stride and block are set to one. If has_cplx_trailing_dim, count.back() = 2.

Parameters

rank	Rank of the underlying dataspace (excluding the possible added imaginary dimension).
has_cplx_trailing_dim	True if the buffer encodes complex values via a trailing dim of size 2 (TRIQS convention).

Definition at line 113 of file array_interface.hpp.

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

• h5/array_interface.hpp