Choice of hierarchy level augmentation in cookbook

graph-tool
1

Hi Tiago,

In your cookbook examples on hierarchical SBMs I have noticed that
frequently you augment the hierarchy to ten levels. Is there a particular
reason for that choice?

Best wishes,

Philipp

2

The number of levels should be large enough to match the inferred depth,
i.e. the last levels should have only one group most of the time. A value of
L=10 is good enough for most purposes.

Best.
Tiago

3

Thank you. I take it that having several single group levels at the "top" is
fine and that the algorithm does not automatically increase the number of
levels if we just stick with the state found by using
gt.minimize_nested_blockmodel_dl? What are the consequences of having
insufficient levels and what are the consequences of having excessive
levels? Is it possible to make general judgements about that?

4

It doesn't automatically adapt the maximum size of the hierarchy. If the
maximum size is too small, then the model might underfit (albeit probably
only very slightly). It can't be too large, so it's better to be safe and
give it enough room.

5

OK, thank you for the clarification.

Best,

Philipp