Auckland - Hash Tables

Link(s)
http://www.cs.auckland.ac.nz/software/AlgAnim/hash_tables.html#hash_anim
Topic(s)
Hashing, Search Algorithms



Recommendation
  
Lecture Aide Has Potential
Self-study Supplement Has Potential
Standalone Has Potential
Debugging Aide Not Recommended
Works?
Yes
Delivery Method(s)
Java Applet
Project
Morris' Collection
Project Relationship
Part of collection
Language(s)
English
Author(s)
John Morris
Institution(s)
University of Auckland
Activity Level(s)
Animation, Canned data, Step control
Source Code License
Unavailable
First Published
N/A
Last Modified
N/A

Description
Web pages give an explanation of hashing. The AV allows user a choice of a couple of collision resolution methods. The focus is more on overall performance of the hash system than on explaining how the given collision resolution method takes place, with a couple of graphs for showing access costs.
Evaluation
The screen is rather busy. It is a bit difficult to figure out what you can do. There is a lot of performance information available, which is helpful. User can run in continuous mode or step mode.The input set of keys is pre-populated and on pressing the next or on using animation, the tool simply pulls up a word from a pre-populated text file and uses it as a key for putting in the hashing table. In case of a collision of the generated hash values, the AV provides re-Hash functionality in the AV window and the tool automatically rehashes the key and puts it in the appropriate place in the hash table. Unfortunately, the does not make clear what hash function is being used. Further, in quadratic probing, the user can not manually input the value of ā€œcā€ used in the hash function, the user is restricted to use any of the three values for it i.e. 1, 2 and 4. The author has used the graphs to plot Collision stats and Hashing Frequency stats to good effect. The coloring scheme is pretty nice and visually appealing.
Usage Notes
Field Report(s)
References
N/A
Rating
0
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AV of the Day
No
Score
37