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1.10.0
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HighFive 2.10.0
HighFive - Header-only C++ HDF5 interface
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HDF5 is configured through what they call property lists. In HDF5 the process has four steps:
hid_t identifying the property list.Note that the mental picture is that one creates a settings object, and then passes those settings to a function such as H5Dwrite. In and of themselves the settings don't change the behaviour of HDF5. Rather they need to be used to take affect.
The second aspect is that property lists represent any number of related settings, e.g. there's property lists anything related to creating files and another for accessing files, same for creating and accessing datasets, etc. Settings that affect creating files, must be passed a file creation property list, while settings that affect file access require a file access property list.
In HighFive the PropertyList works similar in that it's a object representing the settings, i.e. internally it's just the property lists HID. Just like in HDF5 one adds the settings to the settings object; and then passes the settings object to the respective method. Example:
// Create an object which contains the setting to
// open files with MPI-IO.
auto fapl = FileAccessProps();
fapl.add(MPIOFileAccess(MPI_COMM_WORLD, MPI_INFO_NULL);
// To open a specific file with MPI-IO, we do:
auto file = File("foo.h5", File::ReadOnly, fapl);
Note that the MPIOFileAccess object by itself doesn't affect the FileAccessProps. Rather it needs to be explicitly added to the fapl (the group of file access related settings), and then the fapl needs to be passed to the constructor of File for the settings to take affect.
This is important to understand when reading properties. Example:
// Obtain the file access property list:
auto fapl = file.getAccessPropertyList()
// Extracts a copy of the collective MPI-IO metadata settings from
// the group of file access related setting, i.e. the `fapl`:
auto mpio_metadata = MPIOCollectiveMetadata(fapl);
if(mpio_metadata.isCollectiveRead()) {
// something specific if meta data is read collectively.
}
// Careful, this only affects the `mpio_metadata` object, but not the
// `fapl`, and also not whether `file` uses collective MPI-IO for
// metadata.
mpio_metadata = MPIOCollectiveMetadata(false, false);
Classes | |
| class | HighFive::PropertyListBase |
| Base Class for Property lists, providing global default. More... | |
| class | HighFive::PropertyList< T > |
| HDF5 property Lists. More... | |
| class | HighFive::RawPropertyList< T > |
| class | HighFive::MPIOFileAccess |
| Configure MPI access for the file. More... | |
| class | HighFive::FileVersionBounds |
| Configure the version bounds for the file. More... | |
| class | HighFive::MetadataBlockSize |
| Configure the metadata block size to use writing to files. More... | |
| class | HighFive::EstimatedLinkInfo |
| Set hints as to how many links to expect and their average length. More... | |
| class | HighFive::Chunking |
| class | HighFive::Deflate |
| class | HighFive::Szip |
| class | HighFive::Shuffle |
| class | HighFive::AllocationTime |
| When are datasets allocated? More... | |
| class | HighFive::Caching |
| class | HighFive::CreateIntermediateGroup |
| class | HighFive::UseCollectiveIO |
| class | HighFive::MpioNoCollectiveCause |
| The cause for non-collective I/O. More... | |
| struct | HighFive::CreationOrder |
| class | HighFive::LinkCreationOrder |
| Track and index creation order time. More... | |
| class | HighFive::AttributePhaseChange |
| Set threshold for attribute storage. More... | |
| interface | PropertyInterface |
| HDF5 file property object. More... | |
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1.10.0