Loom is an efficient file format for large omics datasets. Loom files contain
a main matrix, optional additional layers, a variable number of row and column
annotations, and sparse graph objects. Under the hood, Loom files are HDF5 and
can be opened from many programming languages, including Python, R, C, C++,
Java, MATLAB, Mathematica, and Julia.

Key features:
* Single file that can be moved around
* Metadata travels with the main data
* Data, clustering, layout, annotation stored together
* Efficient random access
* Automatic, on-the-fly compression
* Out-of-memory data processing
* Open source, BSD license

WWW: https://loompy.org/