Recommendation

Has Potential

Link

http://www.cs.auckland.ac.nz/software/AlgAnim/mat_chain.html#mat_chain_anim

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

Woi Ang; John Morris

Institution

University of Auckland

Project

Morris' Collection

RelationshipToProject

PartOfCollection

Works

Yes

Description

This a visualization of chained matrix multiplication using dynamic programming to find the optimal multiplication ordering. The main page is a textual description of why finding an optimal ordering for matrix chain multiplication is important and some explanation of how it works. The visualization itself shows the assorted tables that need to be built and walks through the process of trying all of the combinations to find the lowest cost ordering. There are only four controls, 'stop', 'run, 'step', and 'skip'. The first three controls are exactly what one would expect, while the skip button jump to different stages of the algorithm based on the number of matrices in consideration (i.e., selecting skip as the first button, jumps forward to the end of computing the cost for all combinations of two matrices).

Evaluation

There is enough here that with a little effort a student could work out what the problem is and how this solution works. The visualization itself has promise, but it could be improved a great deal. There is a certain sloppiness to it that detracts from its effectiveness. The control buttons are all the wrong size, the the labels are all clipped to three letters. Some of the animation steps try to display several blocks of text, and they end up flashing on the screen without leaving the user time enough to read them. On the other hand, in an effort to really indicate where values come from, there is a fairly slow animation of the numbers sliding out of the table and into equations. Unfortunately, after a few frames of animation, the context is lost and while the number can still be seen traveling along, there is no indication where it came from. Simply highlighting the cell in the table would have been more effective. There are also a number of informative text messages that pop up in odd places, sometimes covering other parts of the display. Aesthetically, the visualization (and the website) is showing its age with the bold, multicolor approach common to the web in the 90's (particularly bad is the glaring yellow border on the visualization). I also would have liked it if the user had some control over the input data set. The data set that they have is a pretty reasonable one, but not being able to change it doesn't allow for much exploration.

ActivityLevel

Step Control; Animation; Canned Data

GoodFor

Lecture Aid; Self Study

Screenshots

Videos

References

HowToUse

First Visited

2006-11-06

Last Visited

2008-07-17

Last Updated

1998

Topic

DynamicProgramming

Community

Edit

You may edit this entry if you have an account.