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COSC431
COSC431 Assignment 1: Write a Search Engine
PREAMBLE DUE DATE:16 April 2021
In the first part of this assignment you will write a parser. In the second you will write an indexer, and in the third
you will write the search engine. Marks will be given for parts one and three only. If your search engine works
then your indexer must work. This assignment is worth 20% of your final mark.
The files you need for this assignment are located in ~andrew/COSC431. The XML file you are to use is
wsj.xml, it is the TREC Wall Street Journal collection. Your search engine must run in less than one second
per query on the machine we mark it on (including startup, input, output, and shutdown).
PART 1: PARSER 10%
Your program will parse the Wall Street Journal collection of documents marked up in XML. They look roughly
like this:
<DOC>
<DOCNO>WSJ920102-0154</DOCNO>
<DOCID>920102-0154.</DOCID>
<HL>Notice to Readers</HL>
<DATE>01/02/92</DATE>
<SO>WALL STREET JOURNAL (J), PAGE 1</SO>
<LP>
<P>Today’s Wall Street Journal appears in two sections, the
second of which is the year-end review of markets.</P>
<P>Rhythm & Blues, Inc. filed for bankruptcy today.</P>
</LP>
</DOC>
Your program will output a stream of tokens suitable for you indexer, one per line with a blank line between each
document. I do not recommend using a standard XML parser as the file is“real world”(i.e. not well formed).
PART 2: INDEXER
Build an inverted-file index of the Wall Street Journal collection. It is obvious to build this on top of your parser
from part 1 of this assignment. You should write the index to disk in whatever format you consider appropriate.
PART 3: SEARCH ENGINE 10%
Your search program will read a query from stdin and produce results on stdout. If it does not then you will
not get any marks for this part of the assignment (we use programs to mark your programs).
Each query will consist of a set of one or more search terms. You are not expected to support phrase, adjacency
or proximity searching – in other words, a document-level index is sufficient. You are not expected to support
wildcard searching or regular expression searching.
For the query, your program will output a separate line for each relevant document. Each line is in 2 columns:
<docno> <rsv>
where <docno> is the contents of the <DOCNO> element in the Wall Street Journal collection and <rsv> is the
retrieval status value (relevance score) that your program has assigned to the document. The output must be sorted
from highest to lowest rsv. You must output all documents that you think are relevant (not just the top-10).
Your program will be tested on your indexes, but using queries you have not seen.
HOW TO SUBMIT YOUR ASSIGNMENT
Submit your program by emailing me a github.com (or equivalent) URL. I will mark the most recent commit.
You will include a README that tells me where, on the department file server, I can find your index; and how
to compile and run your programs. You must NOT include the wsj.xml or your indexes in your github archive.
