hierarchy-class: A class for indexing a hierarchy in a model
In sakrejda/hierarchy: Package for handling inputs to hierarchical models.

The class holds hierarchical relationships over all timepoints, and can return indexes for any given level and all parents.

get_hierarchy_idxs(timepoint = NULL): Get a matrix with the indexes of all levels of the hierarchy, with onoe entry per bottom-level node. This format produces redundancy at the higher levels (a given higher-level parameter will appear multiple times) because that allows it to represent the hierarchy clearly even when not all parts have the same number of levels.
get_level_idxs(level_name, timepoint = NULL): Get the indexes for all parameters at a given level.
get_parent_idxs(idxs, timepoint = NULL): Get the indexes of the parents of a given set of indexes. This is relevant if the hierarchy is not cleanly split into K levels for all indexes.
get_size(timepoint = NULL): Get the number of parameters in the _entire_ hierarchy at a given timepoint, including the zero parameter.
get_table(timepoint = NULL): Method to retrieve the state of the hierarchy at a given point in time (date)
get_vectorized_hierarchy(timepoint = NULL): Get a list of three vectors: 1) the matrix of all hierarchy indexes collapsed into a single vector; 2) the location in the vector where each level start; and 3) the location (index) in the vector where each level ends.
initialize(files, ...): Construct hierarchy from given relationship files.