File:BDD Variable Ordering Good.png

BDD_Variable_Ordering_Good.png (156 × 435 pixels, file size: 10 KB, MIME type: image/png)

Summary

Description BDD graph for the Boolean formula x1 * x2 + x3 * x4 + x5 * x6 + x7 * x8 using a good variable ordering
Date
Source self-made using CrocoPat, a tool for relational programming, and GraphViz dot, a tool for graph layout
Author Dirk Beyer
Permission
(Reusing this file)
GFDL and cc-by-sa-2.5
Other versions

The diagram in SVG format is externaly available [1],

but should be uploaded as soon as WikiMedia supports that file format.

The PNG picture is 156 x 435 pixel.

Other BDD pictures for similar formulas:

The following is the RML (Relational Manipulation Language) code that I fed to CrocoPat to produce the GraphViz dot files:

// RML program to generate BDD graphs for the formula
// x1 & x2 | x3 & x4 | x5 & x6 | x7 & x8,
// using two different variable orderings.
// "crocopat -e BDD_Variable_Ordering.rml" generates two files in dot format.
// "dot -Tsvg BDD_Variable_Ordering_Bad.dot -o BDD_Variable_Ordering_Bad.svg"
// generates a file in SVG format from the file in dot format.

// There are two ('Boolean') values for the variables x1, ..., x8.
DOM("0");
DOM("1");

// F is the name of the Boolean formula.
F(x1,x2,x3,x4,x5,x6,x7,x8) :=  (x1="1" & x2="1") 
                             | (x3="1" & x4="1")
                             | (x5="1" & x6="1")
                             | (x7="1" & x8="1");

// Prints the BDD as graph in GraphViz dot format,
// using a good variable ordering resulting in linear size of the graph.
PRINT GRAPH( F(x1,x2,x3,x4,x5,x6,x7,x8) ) 
      TO "BDD_Variable_Ordering_Good.dot";

// Prints the BDD as graph in GraphViz dot format,
// using a bad variable ordering resulting in exponential size of the graph.
// The first term of the conjunction sets the variable ordering.
PRINT GRAPH( TRUE(x1,x3,x5,x7,x2,x4,x6,x8) &
             F(x1,x2,x3,x4,x5,x6,x7,x8) ) 
      TO "BDD_Variable_Ordering_Bad.dot";;


Licensing

I, the copyright holder of this work, hereby publish it under the following licenses:
GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
This licensing tag was added to this file as part of the GFDL licensing update.
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
You may select the license of your choice.

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1 September 2005

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1a8d831bde2bd9b72a5cf0550a0e73953d031c14

10,166 byte

435 pixel

156 pixel

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Date/TimeThumbnailDimensionsUserComment
current09:46, 1 September 2005Thumbnail for version as of 09:46, 1 September 2005156 × 435 (10 KB)Dirk Beyer{{Information| |Description = BDD graph for the Boolean formula x1 & x2 | x3 & x4 | x5 & x6 | x7 & x8 using a bad variable ordering |Source = self-made |Date = 2005-09-01 |Author = Dirk Beyer |Permission = GFDL and cc-by-sa-2.5 |other_

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