GRF_IO
GRF files
Read and Write Utilities

GRF_IO is a MATLAB library which reads or writes a GRF file containing information about an abstract graph.

The file includes information about

• adjacency, that is, which nodes are connected to a given node;
• embedding, that is, how to place each node in the unit square so that a drawing of the graph is visually pleasing and "readable".

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

GRF_IO is available in a C++ version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

FLOYD, a MATLAB library which implements Floyd's algorithm for finding the shortest distance between pairs of nodes on a directed graph.

GRAFFITI, a dataset directory which contains 195 abstract graphs, with adjacency and embedding information, stored in the GRF format.

GRAPH_REPRESENTATION, a data directory of examples of ways of representing abstract mathematical graphs

GRF, a data directory which contains a description of the GRF format and some examples.

GRF_DISPLAY, a MATLAB program which reads a GRF file defining a mathematical graph and displays it in the MATLAB graphics window.

GRF_DISPLAY_OPENGL, a C++ program which reads a GRF file defining a mathematical graph and displays it in an OpenGL graphics window.

GRF_TO_EPS, a FORTRAN90 program which can make an encapsulated PostScript image of a GRF file.

GRF_TO_XYL, a FORTRAN90 program which converts information describing the adjacency and embedding of an abstract graph from GRF to XYL format.

Reference:

1. Peter Eades, Ian Fogg, David Kelly,
   SPREMB: A System for Developing Graph Algorithms,
   Congressus Numerantium,
   Volume 66, December 1988.
2. Stephen Skiena,
   Implementing Discrete Mathematics: Combinatorics and Graph Theory in Mathematica,
   Addison Wesley, 1990.
3. http://www.combinatorica.com/
   the COMBINATORICA web page.

• grf_data_print.m, prints the data of a GRF file.
• grf_data_read.m, reads the data of a GRF file.
• grf_data_write.m, prints the data to a GRF file.
• grf_example.m, sets up a GRF example.
• grf_example_size.m, sizes a GRF example.
• grf_header_print.m, prints the header of a GRF file.
• grf_header_read.m, reads the header of a GRF file.
• grf_header_write.m, writes the header of a GRF file.
• grf_write.m, writes a GRF file.
• s_len_trim.m, returns the length of a string to the last nonblank.
• s_word_count.m, counts the words in a string.
• timestamp.m, prints the current YMDHMS date as a time stamp.

Examples and Tests:

• grf_io_test.m, a sample calling program.
• grf_io_test01.m, demonstrates the use of GRF_WRITE.
• grf_io_test02.m, demonstrates the use of GRF_HEADER_READ and GRF_DATA_READ.
• grf_io_test_output.txt, the output file.
• coxeter.grf, a GRF file created by one test and read by another.

You can go up one level to the MATLAB source codes.