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To: cs551@merlot.usc.edu
Subject: Re: Bitvectors and keywords 
Date: Wed, 18 Apr 2007 07:42:47 -0700
From: william@bourbon.usc.edu

Someone wrote:

  > If i keep a multimap structure for storing the bitvectors created
  > by the keywords in the metadata file, so as every bitvectors
  > maps a set of keywords and the file containing them then i really
  > dont feel any need of keeping the Keywords index
  > structures to quiken the search operation coz then we would be
  > incorporating redundancy in the logic and code.
  > (END to END argument... ;) :)

Please remember that one of the main "escape clause" for the
end-to-end argument is efficiency.  And the main point of
having an index structure is to introduce redundancy to speed
up certain operations.

>From your description, even though it's an improvement over
traditional data structures, it doesn't scale as well as the
bit-vector approach.

  > Do i still  require extra keywords index then??

Yes.  Please see the grading guidelines on "minu points".
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>