invlist_and -- invreted index toy program
  by Yoshihiko Suhara (sleepy_yoshi)


* About
This program is a toy program, which aims to help to someone who studies
about search engines, especially AND retrieval with inverted indexes.


* How to use?
You must change the current directory to the directory that has index files.

===
% cd index
% ls
foo fuga hoge piyo
% ../invlist_and foo fuga hoge piyo
inverted lists for input query ===
foo -> 7: 1 5 6 7 8 9 10
fuga -> 3: 1 4 5
hoge -> 5: 1 2 3 4 5
piyo -> 2: 4 5

ordered list===
piyo -> 2: 4 5
fuga -> 3: 1 4 5
hoge -> 5: 1 2 3 4 5
foo -> 7: 1 5 6 7 8 9 10

Intersection of piyo and fuga: 4 5
Intersection of last result and hoge: 4 5
Intersection of last result and foo: 5

search result ===
result num: 1
5
===


* Index format
===
% cat hoge
5 1 2 3 4 5
===
First number '5' means document frequency (DF) of this inverted list.
Following numbers indicate document IDs that contain the word 'hoge'.


* See also
There's more details about this program in a blog article below. (in Japanese)
http://d.hatena.ne.jp/sleepy_yoshi/20091009/p1