B-Trees - Algoviz Wiki

Works

Yes

Description

Demonstrates building a particular variant of a 2,3,4 Tree (B-Tree of order 4). Note that this demonstration is rather specific to 2,3,4 Trees, and can't really be viewed as a "typical" instance of how B-trees work in general. In particular, the rules for pre-splitting internal nodes on the way down during an insertion are specific to the 2,3,4 Tree.

Evaluation

Sophisticated use of pseudocode, that can expand to show more or less detail. Has an explanation window for how the data structure works. Slightly limited in that it doesn't support delete, but does a good job at what it does support. As an extra bonus, you can pop open another window that shows the corresponding Red Black Tree (though with no pseudocode or explanation).

Animation; Step Control; Canned Data; Random Data

Lecture Aid; Self Study

Screenshots

Videos

References

The link above takes you to the AIA demonstration index page. Click on the link to the desired AV, and it should load in your browser as a multi-paned Java applet. Note that the level of detail shown in the visualization is directly tied to the level of detail that you choose to expose in the pseudocode pane.

First Visited

2008-07-02

Last Visited

2010-02-10

Last Updated

2000

Topic

Community

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http://www.cs.hut.fi/Research/TRAKLA2/exercises/BTree_insert.html

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Trakla - B-Tree

Recommendation

Has Potential

Link

Delivery Method

Java Application

License

GPL

Language

English

Author

Ville Karavirta; Ari Korhonen; Lauri Malmi; Kimmo Stålnacke

Institution

Helsinki University of Technology

Project

Trakla2

Works

Yes

Description

An exercise allowing the user to build a B-tree by dragging node values into nodes and issuing split commands.

Evaluation

Somewhat confusing, since the exercise instructions are poor. Once the student figures out how to use it, it should be reasonably effective. This AV does not stand on its own, the user must come to this with a knowledge of how the B-tree works.

Canned Data; Predictions

Lecture Aid; Self Study; Lab Exercise

Screenshots

Videos

References

First Visited

2008-07-29

Last Visited

2008-07-29

Last Updated

2006-01-25

Topic

Community

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http://www.csanimated.com/animation.php?t=B-tree

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CS Animated - B-Tree

Recommendation

Has Potential

Link

Delivery Method

Flash

License

Non-Commercial

Language

English

Author

Bill Jacobs

Institution

None

Project

Jacobs' AV Lectures

PartOfCollection

Works

Yes

Description

A multimedia lecture, with audio used to explain the data structure and a series of slides for the visual component. Each slide has its own video component, so it is easy to move through the lecture. Each slide has flash animation as appropriate.

Evaluation

Not interactive, but in that sense it is certainly no worse than a standard animation. The presentations are clear.

Animation Only; Canned Data

Self Study

Screenshots

Videos

References

First Visited

2008-06-23

Last Visited

2008-06-23

Last Updated

2008-06-01

Topic

Community

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http://people.ksp.sk/~kuko/bak/

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Kovac's visualisation of B trees

Recommendation

Unrated

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

Kubo Kovac

Institution

Comenius University, Slovakia

Project

Kovac's Tree Project

Works

Yes

Description

This AV shows various search trees such as AVL, BST, B tree, red-black tree, AA tree, skiplist, heap, treap, scapegoat tree and splay tree. It demonstrates insertion, deletion and search. Users can start with randomly generated input dataset or user's own data. For the data structuers where this is relevent, it provides balance factors such as ‘+’, ‘-‘ and ‘.’ by the nodes.

Evaluation

Strengths: The best feature of this tool is to provide many search trees. This may allow learners to identify how the search trees work by comparison with each other. Randomly generated dataset lets users quickly see the structure of the tree. Users can also construct their own data set. Weaknesses: Like many tree AVs, it just shows the result of the insert or delete operation, without explaining how it works. What is neeed is good textual explanation about each search structure and documentation explaining basic key concepts such as balance factors, re-balancing, etc. The text size of balance factors on the nodes is too small to be recognized (you need to use the "big" version of the applet to see them at all).

Exploring the Concept; Comparison; Lecture Aid

Screenshots

Videos

References

First Visited

2007

Last Visited

2008-06-12

Last Updated

2007

Topic

Community

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http://dbs.mathematik.uni-marburg.de/research/projects/dsn/

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Data Structures Navigator - (a,b)-trees

Recommendation

Has Potential

Link

Delivery Method

Java Application

License

Unavailable

Language

English

Author

Jens-Peter Dittrich; Jochen van den Bercken; Tobias Schäfer; Marcus Klein

Institution

Phillips-University of Marburg

Project

Data Structure Navigator

Works

Yes

Description

Supports several variations on the B-tree, which includes the 2-3 tree. Users provide values to be inserted/found/deleted.

Evaluation

Fairly clear presentation, nice graphics, easy to use. Clearly shows the various steps of moving values between the nodes of the tree. However, there is no explanation for the steps that are taking place, and so it can be difficult to follow the action. For the trees of higher degree, it can be rather tedious entering data (there is no mechanism for generating random data streams).

Step Control; Animation; User Data

Lecture Aid; Self Study; Debugging

Screenshots

Videos

References

First Visited

2006-09-01

Last Visited

2008-07-16

Last Updated

2000-07-31

Topic

Community

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http://www.cs.usfca.edu/galles/visualization/download.html

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Data Structure Visualization - 2-3 Tree

Recommendation

Has Potential

Link

Delivery Method

Java Application

License

Unlicensed Sourcecode

Language

English

Author

David Galles

Institution

University of San Francisco

Project

Data Structure Visualization

Works

Yes

Description

Allows user to insert, find, and delete values in a 2-3 Tree. Animation is used to show the action. Users see the process of a node being inserted at the leaf node, and splits moving upward in the tree.

Evaluation

Somewhat limited by the fact that there is no code or explanation for what is happening. When a value is inserted or deleted, an animation takes place that the user has little control over (other than overall speed). It can be rather hard to grasp what is happening with various split and merge operations.

Animation Only; User Data

Lecture Aid; Debugging

Screenshots

Videos

References

First Visited

2006-09-01

Last Visited

2008-07-01

Last Updated

2006-04-05

Topic

Community

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http://www.cs.usfca.edu/galles/visualization/download.html

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Data Structure Visualization - B-Tree (Proactive Split/Merge)

Recommendation

Has Potential

Link

Delivery Method

Java Application

License

Unlicensed Sourcecode

Language

English

Author

David Galles

Institution

University of San Francisco

Project

Data Structure Visualization

Works

Yes

Description

Demonstrates the behavior of a B-Tree of degree 4. Users give data values to insert, find, and delete.

Evaluation

There is no code or explanation of what is happening. Users do not control the degree of the tree. When an insert or delete is initiated, an animation takes place of the various split or merge steps. The user cannot control this (aside from the overall animation speed). Thus, it can be difficult to follow the details of what is happening.

Animation Only; User Data

Lecture Aid; Debugging

Screenshots

Videos

References

First Visited

2006-09-01

Last Visited

2008-07-01

Last Updated

2006-04-05

Topic

Community

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http://www.cosc.canterbury.ac.nz/mukundan/dsal/TwoThreeTree.html

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Java Applets Centre - 2-3 Tree (Insert)

Recommendation

Not Recommended

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

R. Mukundan

Institution

University of Canterbury

Project

Java Applets Centre

Works

Yes

Description

User enters values (or asks for a random value to be generated). Each value is then added to the 2-3 tree. The 2-3 tree is just updated to show the revised tree with the new value added -- there is no explanation or visualization of the insertion process.

Evaluation

User can see the tree being built up. But there is no other explanation or use to this.

Lecture Aid; Debugging

Screenshots

Videos

References

First Visited

2008-04-29

Last Visited

2008-07-21

Last Updated

2006

Topic

Community

Average rating:	unrated
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http://www.cs.auckland.ac.nz/software/AlgAnim/n_ary_trees.html#btree_anim

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Auckland - B-Tree Animation (n-ary trees)

Recommendation

Not Recommended

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

JungHo Yoo; ChangHwan Park; John Morris,

Institution

University of Auckland

Project

Morris' Collection

PartOfCollection

Works

Yes

Description

Shows construction of a 2-3-4 tree (B-tree of order 4)

Evaluation

Somewhat confusing UI. Not clear if the animation is meant to show a line of node values moving to the target point of if this is a bug. But it seems to work, once you figure out how to get it started.

Step Control; Animation; Canned Data

Lecture Aid

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2008-07-17

Last Updated

2004

Topic

Community

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http://slady.net/java/bt/view.php?w=600&h=450

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Java B-Tree Applet Animation

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

Petr Sladek

Institution

None

Project

Works

Yes

Description

This B-tree applet can simulate certain fixed sized from 2-3 trees up to 5-9 trees. B-trees only, no B+-trees.

Evaluation

Strengths: simple UI, nice animation. Weaknesses: No speed control on the animation, so it gets a bit tedious (wish it could be spead up after awhile). Nonstandard terminology (what he calls a "B-Tree of order 1" is a 2-3 Tree, usually called a "B-tree of order 3"). No explanation of what is occurring, you just see the insert/delete take place in the animation. Occasional deletion bugs (numbers don't always disappear when they are removed).

Lecture Aid; Teaching the Concept; Debugging

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2006-08-17

Last Updated

2005

Topic

Community

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http://sky.fit.qut.edu.au/~maire/baobab/baobab.zip

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BAOBAB

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Language

English

Author

Frederic Maire

Institution

Queensland University of Technology

Project

Works

Yes

Description

An interesting take on B-trees, but needs some fixing to be great.

Evaluation

Strengths: innovative "show last figure" command. Weaknesses: no animation; no explanation as to what's going on; somewhat confusing UI; lexicographic ordering of numbers.

Debugging

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2006-08-17

Last Updated

2004-02-25

Topic

Community

Average rating:	unrated
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http://www.seanster.com/BplusTree/BplusTree.html

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B+ Trees

Recommendation

Unrated

Link

Delivery Method

Java Applet

License

Language

English

Author

Kristi Thompson and Sean Mclaughlin

Institution

Queen's University

Project

Works

Yes

Description

A B+tree insertion visualization. Not sure how this could be used in a teaching environment (it was a class project to demonstrate understanding).

Evaluation

Strengths: shows how sortable keys may be used to index data; animated / Weaknesses: somewhat confusing UI; no explanation of what's occurring

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2006-08-17

Last Updated

1997

Topic

Community

Average rating:	unrated
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http://www.cse.ohio-state.edu/~bondhugu/acads/234-tree/index.shtml

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Animated Working of a Two-Three-Four Tree

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

GPL

Language

English

Author

Uday Kumar Reddy Bondhugula

Institution

Ohio State University

Project

Works

Yes

Description

A decent take on a 2-3-4 tree.

Evaluation

Strengths: different modes, including step-by-step; animations showing what's happening. Weaknesses: slightly confusing UI; doesn't clearly explain the steps taking place.

Teaching the Concept; Debugging

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2006-08-17

Last Updated

2004

Topic

Community

Average rating:	unrated
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http://www.geocities.com/SiliconValley/Program/2864/File/btree.html

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2-3-Tree Animation

Recommendation

Not Recommended

Link

Delivery Method

Java Applet

License

Unlicensed Sourcecode

Language

English

Author

Min Jeoung Sig

Institution

University of Myong Ji

Project

Works

Description

This 2-3 tree is mislabeled as a B-tree. You can't even see what procedure the algorithm goes through as it inserts data into the tree.

Evaluation

Strengths: UI reasonably easy to use. Weaknesses: No animation showing what occurs--the tree instantly adjusts itself to new configurations; no explanation of what has occurred.

Debugging

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2010-02-11

Last Updated

1999-03-01

Topic

Community

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http://www.cs.unm.edu/~rlpm/499/ttft.html

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Graphical 2-3-4 Tree

Recommendation

Has Potential

Link

Delivery Method

Java Applet

License

Unavailable

Language

English

Author

Rory L. P. McGuire

Institution

University of New Mexico

Project

Works

Yes

Description

Animation for 2-3-4 Tree. Shows the path that the entry goes through as it is inserted into the tree. But since it is an animation, it is hard to grasp the steps by carefully examining them.

Evaluation

Strengths: different speeds; easy UI. Weaknesses: no stepwise operation; could benefit from more explanation of what is occurring.

Lecture Aid; Exploring the Concept; Debugging

Screenshots

Videos

References

First Visited

2006-08-17

Last Visited

2008-06-13

Last Updated

2004-12-07

Topic

Community

Average rating:	unrated
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Edit

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JHAVÉ - 2-3-4 Tree

Recommendation

Not Recommended

Link

http://jhave.org/learner

Delivery Method

Java Web Start

License

CreativeCommons

Language

English

Author

Tom Naps

Institution

University of Wisconsin - Oshkosh

Project

JHAVÉ

Works

Yes

Description

Visualization of basic 2-3-4 Tree insert.

Evaluation

The AV is set up as a series of "slides" in one pane, and pseudocode in the adjacent pane. As the user steps through the "slides", the associated pseudocode is highlighted. Occasional questions pop up for the user to answer. For a small canned data set, shows 2-3-4 Tree insertion. The nodes are not laid out well, and the data do not fit on the nodes properly. This appears to be a work-in-progress.

Step Control; Questions; Canned Data

Lecture Aid

Screenshots

Videos

References

Clicking on the link above will take you to a login page for Jhave. If you do not want to create an account at jhave.org, use anonymous@anonymous.com as your user name and anonymous as your password when you are asked to login. You will then be taken to the Jhave page for this AV. Some Jhave AVs include a tutorial on how the AV itself or the underlying algorithm works. At the bottom are links to the AV (you can run it with a built-in quiz system on or off). The first time you try to run any Jhave exercise, you will have to download the Jhave webstart application. This should happen automatically when you click the link. (You might need to install Java WebStart if it is not on your machine.) Once you download the Jhave application, the AV should start automatically. You can then step through the AV by repeatedly clicking the right arrow button. Occasionally, you will be given a multiple-choice or short-answer question to answer.

First Visited

2008-07-08

Last Visited

2008-07-10

Last Updated

2008-07-01

Topic

Community

Average rating:	unrated
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http://www.animal.ahrgr.de/showAnimationDetails.php3?lang=en&anim=8

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Animal - B+ Tree Insertion

Recommendation

Not Recommended

Link

Delivery Method

Animal Animation

License

Non-Commercial

Language

English; German

Author

Carla Castellano; David Francis; Angelo Sarto

Institution

TU Darmstadt, Darmstadt, Germany

Project

Animal

Works

Yes

Description

Shows a small insertion example in a B+ Tree. Presented as a series of slides.

Evaluation

Pretty well incomprehensible. Not sure if there is something buggy about this AV, or if that is just the way it is.

Animation; Step Control; Canned Data

Nothing

Screenshots

Videos

References

For detailed instructions on how to install Animal and run Animal AVs, see: http://www.algoanim.info/Animal2/?q=node/290. Once you have installed the Animal .jar file and downloaded/unpacked the .zip file of Animal animations, you are now ready to run Animal. Run the .jar file to start Animal. Then go to the "Open" menu item, and browse to where you put the animal animations you got in the .zip file. Pick this AV from the list. You can then step through the animation, or use "kiosk mode" to have the steps fed to you at a constant pace.

First Visited

2007-07-21

Last Visited

2010-02-04

Last Updated

2000-05-17

Topic

Community

Average rating:	unrated
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