openPMD::Dataset Class Reference

Public Types
enum	: std::uint64_t { JOINED_DIMENSION = std::numeric_limits<std::uint64_t>::max() , UNDEFINED_EXTENT = std::numeric_limits<std::uint64_t>::max() - 1 }

Public Member Functions
	Dataset (Datatype, Extent, std::string options="{}")
	Dataset (Extent={UNDEFINED_EXTENT})
	Constructor that sets the datatype to undefined.
Dataset &	extend (Extent newExtent)
bool	empty () const
std::optional< size_t >	joinedDimension () const
bool	undefinedExtent () const

Static Public Member Functions
static std::optional< size_t >	joinedDimension (Extent const &)
static bool	undefinedExtent (Extent const &)

Public Attributes
Extent	extent
Datatype	dtype
uint8_t	rank
std::string	options = "{}"
	backend-dependent JSON configuration

Friends
class	RecordComponent

Member Enumeration Documentation

anonymous enum

anonymous enum : std::uint64_t

Enumerator
JOINED_DIMENSION	Setting one dimension of the extent as JOINED_DIMENSION means that the extent along that dimension will be defined by the sum of all parallel processes' contributions. Only one dimension can be joined. For store operations, the offset should be an empty array and the extent should give the actual extent of the chunk (i.e. the number of joined elements along the joined dimension, equal to the global extent in all other dimensions). For more details, refer to docs/source/usage/workflow.rst.
UNDEFINED_EXTENT	In some use cases, the extent needs not be specified. For these, specify Extent{UNDEFINED_EXTENT}. Use cases: Some backends (i.e. JSON and TOML in template mode) support the creation of datasets with undefined datatype and extent. The extent should be given as {UNDEFINED_EXTENT} for that. With openPMD 2.0, the shape of constant components may be omitted in writing if it is defined somewhere else as part of the same Mesh / Species. (https://github.com/openPMD/openPMD-standard/pull/289) When reading such datasets, the openPMD-api will try to fill in the missing extents, so the extent for constistently-defined datasets should ideally not be reported by the read-side API as undefined.

Constructor & Destructor Documentation

Dataset()

openPMD::Dataset::Dataset

(

Extent

e = {UNDEFINED_EXTENT}

)

Constructor that sets the datatype to undefined.

Helpful for:

1. Resizing datasets, since datatypes need not be given twice.
2. Initializing datasets as undefined, as used by template mode in the JSON/TOML backend. In this case, the default (undefined) specification for the Extent may be used.

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

• /tmp/tmp.NhLRcLhrNZ/openPMD-api/include/openPMD/Dataset.hpp
• /tmp/tmp.NhLRcLhrNZ/openPMD-api/src/Dataset.cpp