HDF5 I/O

The h5stream utilities provide a compact file-based interface for storing and loading HDF5 datasets used in NRG workflows, including eigenvalues, operator data, and saved iteration results.

How the wrapper maps data to HDF5

h5stream::h5stream owns an HDF5 file handle and exposes typed read and write helpers. Its constructor opens the file in one of four modes: r for read-only, rw for read/write, x for exclusive creation, or tr to create or truncate the file. The default mode is tr, so opening an existing path with the default will replace its contents.

Before writing, get_datatype_for_hdf5 maps supported C++ scalar types to their native HDF5 types. A vector is stored as a one-dimensional dataset; nested vectors are written as a sequence of datasets with numeric suffixes appended to the base name. The matching nested-vector reader loads that sequence in order. Raw pointer-and-size overloads support callers that already manage contiguous storage.

Metadata is stored as HDF5 attributes. The dspace and gspace helpers bind attribute operations to a dataset or group, while getDataspace, getGroup, and createGroup provide the corresponding file navigation operations. Call close when file access is complete.

For the generated class reference, see the h5stream::h5stream class documentation.