datamade/datamade-pysettrie

Name: datamade-pysettrie

Owner: datamade

Description: Set-Tries

Created: 2017-09-20 18:19:11.0

Updated: 2017-09-21 09:40:04.0

Pushed: 2017-09-20 20:26:31.0

Homepage: null

Size: 331

Language: Python

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README

pysettrie

https://github.com/mmihaltz/pysettrie

pysettrie is a python3 package that provides support for efficient storage and querying of sets of sets using the trie data structure, supporting operations like finding all the supersets/subsets of a given set from a collection of sets. The original motivation for this module was to provide efficient search for supersets of sets of feature-value pairs in our natural language parser project (e.g. matching nouns against verb argument positions).

The following classes are included:

• SetTrie: set-trie container for sets; supports efficient supersets/subsets of a given search set calculations.
• SetTrieMap: mapping container using sets as keys; supports efficient operations like SetTrie but also stores values associated to the key sets.
• SetTrieMultiMap: like SetTrieMap, but supports multiple values associated to each key.

For further information, please see documentation

Module test_settrie.py contains unittests for all the containers.

Author: Márton Miháltz https://sites.google.com/site/mmihaltz/

This package depends on the sortedcollection module. One recommended way to install (tested on Ubuntu):

 pip3 install sortedcontainers

If you don't have pip3:

 apt-get install python3-setuptools
 easy_install3 pip

pysettrie is partly based on: I.Savnik: Index data structure for fast subset and superset queries. CD-ARES, IFIP LNCS, 2013. http://osebje.famnit.upr.si/~savnik/papers/cdares13.pdf Remarks on paper:

• Algorithm 1. does not mention to sort children (or do sorted insert) in insert operation (line 5)
• Algorithm 4. is wrong, will always return false, line 7 should be: “for (each child of node labeled l: word.currentElement <= l) & (while not found) do”
• the descriptions of getAllSubSets and getAllSuperSets operations are wrong, would not produce all sub/supersets

See also:

• http://stackoverflow.com/questions/9353100/quickly-checking-if-set-is-superset-of-stored-sets
• http://stackoverflow.com/questions/1263524/superset-search?rq=1

Changes:

• Version 0.1.3:
• SetTrieMultiMap.assign() returns number of values associated to key after assignment.

Licensed under the GNU LESSER GENERAL PUBLIC LICENSE, Version 3.