Networkflow - Algoviz Wiki

PartOfProject

Works

Yes

Description

After specifying the name of a data file that contains a graph, the user is shown the graph (with its current flows) and the current residual graph. The user can then step through (or run in animation mode) to see each augmenting path and its effect on the residual graph.

Evaluation

The presentation of the augmenting paths and their effect on the residual graph is clear, shown step-by-step with accompanying text descriptions. While this AV is probably better than the alternatives, it is not rated "Recommended" because there are a lot of annoying aspects to the user interface. You have to know the names of the available data files. You can't reset the visualization, you have to restart the application. The animation speed makes it impractical to run in animation mode (but step mode is more appropriate for this algorithm presentation anyway). The idea for the AV presentation is great if it could be cleaned up a little bit.

Animation; Step Control; Canned Data

Lecture Aid; Self Study

Screenshots

Videos

References

First Visited

2006-11-08

Last Visited

2008-07-03

Last Updated

1996

Topic

Community

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http://www-b2.is.tokushima-u.ac.jp/~ikeda/suuri/maxflow/Maxflow.shtml

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TokushimaFlow

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Unlicensed Sourcecode

Language

English

Author

Kenji Ikeda

Institution

Tokushima University

Project

Works

Yes

Description

The web page states the maximum flow and minimum cut problem and describes the Ford-Fulkerson algorithm to find the maximum flow. The description is followed by a series of links to examples each of which points to a fixed graph. The example page displays an applet containing the graph and the residual graph. The graph displays the flow on the edge and the capacity of the edge. The residual graph displays the flow on each edge. The user can step through the algorithm by clicking on the graph. On clicking the graph, a path from the source to the sink is highlighted and the flow values along the path are updated. The residual graph is appropriately updated.

Evaluation

This simple applet explains the maximum flow problem reasonably well. The graphs are clearly laid out. The idea of separating the graph from the residual graph works to prevent confusion. The color scheme is satisfactory. On completion, the applet cycles back to the start on a mouse click. Clearly signaling the end of the algorithm would better help the uninitiated. While the visualization rightly does away with a lot of unnecessary customization related options, more modes of interactivity could immensely improve the user's productivity. For example, the user could be asked to identify an s-t path or fill in the flow values on the edges. In this visualization, user interactivity is limited to stepping through the algorithm. For this particular algorithm, a previous button could be helpful. Supporting explanation text would definitely aid understanding.The examples could be integrated into a single applet (the user could choose a particular example form a drop down box).

Lecture Aid

Screenshots

Videos

References

First Visited

2008-04-06

Last Visited

2008-04-06

Last Updated

2006-06-26

Topic

Community

Average rating:	3.0
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http://www.cs.pitt.edu/~kirk/cs1501/animations/Network.html

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Network Flow

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

Thanarat Horprasert Chalidabhongse

Institution

University of Maryland

Project

Works

Yes

Description

The applet lets the user construct an input for the Network Flow problem using a graphical user interface and execute the Ford-Fulkerson algorithm on it in one go or one augmenting path at a time. The visualisation displays the graph and the associated flows and capacities.

Evaluation

The graphical representations used are clear and mostly obvious. The applet does not explain the algorithm in detail; after each step, it simply displays the current flow through the network. In other words, it provides little assistance in understanding how augmenting paths are chosen; in fact, it does not even explicitly display the augmenting paths. Therefore, some familiarity with the algorithm is likely to be helpful in making use of the applet. It is rather a nuisance that the only option is to enter your own graph, with no good examples provided.

Lecture Aid; Self Study

Screenshots

Videos

References

First Visited

2007-09-26

Last Visited

2007-09-26

Last Updated

1996

Topic

Community

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http://users.uom.gr/~thanasis/JAVENGA.html

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JAVENGA Network Flow

Recommendation

Unrated

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

Baloukas Athanasios

Institution

University of Macedonia, Department of Applied Informatics, Thessaloniki, Greece

Project

JAVENGA

PartOfProject

Works

Yes

Description

The software features static visualizations for Graph and Network Algorithms. More specifically it illustrates: BFS and DFS traversals; topological sorting; various shortest path algorithms; Minimum Spanning tree algorithms of Prim and Kruskal; and the Primal Network Simplex Algorithm for the balanced Minimum Cost Network Flow Problem. There are two versions of the network flow algorithm. They do the same thing, but one has a smoother animation. Once a graph is entered, select one of the versions of the Network Simplex visualization. Then either repeatedly click the "Step Forward" button, or set the speed and click the "Run Algorithm" button.

Evaluation

http://algoviz.org/node/194; http://algoviz.org/node/197

Teaching the Concept; Exploring the Concept

Screenshots

Videos

References

You can use this as a Java Applet (click on link above) or get the Java .jar file at http://users.uom.gr/~thanasis/JAVENGA.html. When you open the applet, you must first enter a graph using the graphical editor (first 3 buttons at the top). You can view the graph representation (4th button). You can choose an algorithm to run (rightmost button at top). You must enter a graph first. The network flow algorithm requires that the graph be balanced. That is, the weights on the nodes must sum to zero.

First Visited

2009-09-02

Last Visited

2009-09-02

Last Updated

2009

Topic

Community

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