The Algorithm Visualization Catalog is a comprehensive collection of links to algorithm visualizations, or AVs.

ALVIE - Closest Pair

Link(s)
http://alvie.algoritmica.org/
Topic(s)
Computational Geometry

Screenshots
ALVIE Closest Pair - 1
Videos


Recommendation
  
Lecture Aide Recommended
Self-study Supplement Recommended
Standalone Recommended
Debugging Aide Not Recommended
Works?
Yes
Delivery Method(s)
Java Application
Project
AlViE
Project Relationship
Part of project
Language(s)
English
Author(s)
Pilu Crescenzi
Institution(s)
University of Florence
Activity Level(s)
Canned data, Step control
Source Code License
Available on request
First Published
N/A
Last Modified
N/A
Awards
AlgoViz.org Award Winner - 2010

Description

Demonstrates a divide and conquer algorithm for computing the closest pair of points within a specified set of points in the Euclidean plane. C-like pseudo-code is included. The visualization tries to mimic as far as possible the animation of the algorithm used by Prof. Ottmann at the University of Freiburg. The visualization shows both the horizontal and the vertical strips used during the merge operation and it uses color to distinguish nodes within a vertical/horizontal strip from nodes out of the strip. Colors are also used to emphasize which nodes and distances are currently under examination. The user can go backward and forward, can zoom in and zoom out, and can set bookmarks. This visualization is easily configurable and localizable.

Evaluation

Simple-to-use user interface for walking through the example, since a good example is already provided with the algorithm. Simply open up the AV (see directions below) and step through the example with pseudo-code. Not clear if one can add data for this particular AV (you can for other ALVIE AVs). As you go through the example, you are directed to the corresponding line in the pseudocode and given a line or two of explanation in the message window. Attractive layout of the data, including colors indicating the current points being considered and an indication of the strip of area within the current maximum distance.

Usage Notes

The link above will take you to the ALVIE website. That page should lead you to a download link. Download and unzip the ALVIE system. Double click on the .jar file. Within the ALVIE pane (not the GRIND pane), click on the "eye" icon (third icon from the left in the toolbar) to get a list of algorithms from which select the AV that you want. Once selected, click OK and step through the AV with the arrow icons.

Field Report(s)
References
N/A
Rating
4
Average: 4 (3 votes)
Your rating: None
AV of the Day
Yes
Score
70