[Boost-users] [Multi-Index] New "hierarchical" indexing?

Subject: [Boost-users] [Multi-Index] New "hierarchical" indexing?
From: Dominique Devienne (ddevienne_at_[hidden])
Date: 2009-07-10 14:29:48

I'm using BMI containers with several indexes, notably an index on the
parent of each entry.

But some of my BMIs have a hierarchical parent-child relationship of
their entries, and I need to answer hierarchical queries like
is-child-of, is-descendant-of, is-ancestor-of, etc...

In another use case, entries have a "scenario" key, where scenario is
hierarchical, and I want all entries in BMI A from a given scenario
and all its ancestors, with the scenarios being in BMI B (i.e.
"cross-bmi"). Of course I can do a "full scan" but I'm looking for
something hopefully faster/smarter.

Has anyone experimented with providing such a specialized index?

At least in one instance, I'm manually keeping a separate container
with all the edges of the DAG to be able to answer such a query, but
then I have to maintain this
"index" separately from the BMI, which is precisely what BMI is
designed to avoid. This is also a solution that is OK in this
particular case (~ 1500 nodes, ~7500 edges), but may be too expensive
for some other graphs with more nodes.

Any input would be appreciated. Thanks, --DD