matlab圖論工具箱

1、 MATGRAPH BY EXAMPLE 27 three one eight five two nine seven four six F IGURE 12. A drawing of a graph read into M ATGRAPH via the graph parser program. F IGURE 13. A picture of Q4 produced by exporting a graph from M ATGRAPH and then laid out using GraphViz. M ATGRAPH can save graphs in a format tha

2、t can be read by OmniGrafe. The M ATGRAPH command graffle(g,filename.graffle writes the graph to disk. Double clicking the created le launches OmniGrafe. Heres an example: cube(g,3 graffle(g,cube.graffle Using OmniGrafes layout tool, we can produce a nice embedding of the graph as shown in Figure 14

3、. 28 EDWARD SCHEINERMAN F IGURE 14. A picture of Q4 produced by exporting a graph from M ATGRAPH and then laid out using OmniGrafe. To a limited extent, it is possible to convert graphs prepared in OmniGrafe for import into M ATInside the matgraph/tools directory resides a program named graffle2sgf.

4、py. This is a Python language program so, in order to run it you must have Python installed on your computer. This program takes as input a graph saved by OmniGrafe and returns as output a matrix specifying the graph in Simple Graph Format (see 9.2. Suppose you have created a graph using OmniGrafe a

5、nd saved it on your hard disk in a le called mygraph.graffle. Issue the following command in the Unix shell: ./graffle2sgf.py mygraph This reads the graph saved by OmniGrafe and writes the relevant data into the le mygraph. Now, inside MATLAB, do the following: load mygraph sgf(g,mygraph g Graph wit

6、h 5 vertices and 6 edges (full The MATLAB command load mygraph reads the le mygraph and saves the matrix contained therein into a variable that is also named mygraph. The command sgf(g,mygraph overwrites g with the graph specied by the SGF matrix mygraph. The graffle2sgf.py tool is not completely re

7、liable. It works well on diagrams that contain only nodes and edges. If there are other extraneous lines or text in the diagram (which an OmniGrafe diagram certainly may have, then the program can get confused and give poor performance. Readers are invited to submit a better version. GRAPH . MORE , D EPARTMENT OF A PPLIED M ATHEMATI