GRF_IO
GRF files
Read and Write Utilities

GRF_IO is a C++ 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 C++ 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 which contains 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_io.cpp, the source code.
• grf_io.hpp, the include file.

Examples and Tests:

• grf_io_test.cpp, a sample calling program.
• grf_io_test.txt, the output file.
• coxeter.grf, a GRF file created by one test and read by another.

List of Routines:

• CH_EQI is true if two characters are equal, disregarding case.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• GRF_DATA_PRINT prints the data of a GRF file.
• GRF_DATA_READ reads the data of a GRF file.
• GRF_DATA_WRITE writes the data of a GRF file.
• GRF_EXAMPLE sets up a GRF example.
• GRF_EXAMPLE_SIZE sizes a GRF example.
• GRF_HEADER_PRINT prints the header of a GRF file.
• GRF_HEADER_READ reads the header of a GRF file.
• GRF_HEADER_WRITE writes the header of a GRF file.
• GRF_WRITE writes a GRF file.
• I4VEC_COPY copies an I4VEC.
• R8VEC_COPY copies an R8VEC.
• S_LEN_TRIM returns the length of a string to the last nonblank.
• S_TO_I4 reads an I4 from a string.
• S_TO_R8 reads an R8 from a string.
• S_WORD_COUNT counts the number of "words" in a string.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C++ source codes.