getting intersection of classifiers

From steve.brophy@altarum.org
DateWed, 26 Jun 2002 16:30:27 -0400
Subject getting intersection of classifiers
Hello list,
Thanks for your help so far. I am making progress, but have another
question:

We would like to present a table, with the rows and colums being the small
set of values from two different metadata. The cells in the table would
be the number of documents which match both metadata values, which is also
a link to a page listing those documents.

What I have tried so far:
Defined metadata fields Publisher and Subject, using the metadata.xml
file, working!
Defined a metadata field 'PubSub' which combines an abbreviated Publisher
and Subject.
Defined a Hierarchy classifier for this combined field:
classify Hierarchy -hfile pubsub.txt -metadata PubSub -sort Title
-buttonname Publishers/Subjects

In the pubsub.txt file, lines like:
GAO 1 "US GAO"
GAO-EDI 1.1 "EDI"
GAO-LOG 1.2 "Logistics Support"
RAND 2 "RAND"
RAND-EDI 2.1 "EDI"
RAND-LOG 2.2 "Logistics Support"

This is working almost like we want -- we can browse down through the
classifier, to get to a list of the intersecting documents. And by using
the [numleafdocs] can also list the number of documents under each
classification combination. So we could hard-code a table which jumped to
these sub-level classifier results and be close. But would need to hard
code the number, as the [numleafdocs] would not be available until getting
down into a specific sublevel.

Question, is this on the right track, or is there an easier way to do it?

If we set up indexes on both of these metadata fields, is there some way
to do a search rather than a browse and get back all documents with these
two specific meta-data values? Also is there a way to pull back the
number of documents meeting these conditions?

So far I've been trying the formats and classifier types, but maybe I
should instead look into the runtime arguments that are available.

Thanks for any ideas. If this isn't supported easily, the normal
classifier browsing should work ok to discover the documents. But want to
come as close as possible to the requested design before telling them it
won't work that way.

Steve Brophy
Altarum, Ann Arbor, MI