Block Hierarchy Meta Data

Problem statement

Several file formats have multiple ways of representing data blocks in hierarchies. The most of important of these are Exodus and SILO. All Exodus data files contain a collection of element blocks. Furthermore, some contain additional meta-data to groups these blocks into hierarchies and also material groups. Similarly, SILO files contains domains and materials. One major difference between the two formats is that, in SILO, domains are element blocks that can contain multiple materials. There is a separate data structure that lists the elements of different materials. Therefore, extract a certain material out of a domain requires reading the whole domain and the list of elements for that material and then extracting those elements out.