FLOYD
Shortest Distances Between Nodes in a Directed Graph

FLOYD is a MATLAB library which demonstrates Floyd's algorithm for finding the shortest distance between every pair of nodes in a directed graph.

Licensing:

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

Languages:

FLOYD is available in a C version and a C++ version and a FORTRAN90 version and a FORTRAN77 version and a MATLAB version.

Related Data and Programs:

CITIES, a MATLAB library which handles various problems associated with a set of "cities" on a map.

CITIES, a dataset directory which contains a number of city distance datasets.

CODEPACK, a FORTRAN90 library which computes "codes" that can determine if two graphs are isomorphic.

DIJKSTRA, a MATLAB program which runs a simple example of Dijkstra's minimum distance algorithm for graphs.

GRAFPACK, a FORTRAN90 library which computes various quantities associated with mathematical graphs.

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_IO, a MATLAB library which reads and writes GRF files.

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

SUBSET, a MATLAB library which generates, ranks and unranks various combinatorial objects.

TABLE_GRAPH_CODE, a FORTRAN90 program which reads a TABLE file describing a graph, and computes its graph code.

Reference:

1. Robert Floyd,
   Algorithm 97: Shortest Path,
   Communications of the ACM,
   Volume 5, Number 6, page 345, June 1962.
2. Michael Quinn,
   Parallel Programming in C with MPI and OpenMP,
   McGraw-Hill, 2004,
   ISBN13: 978-0071232654,
   LC: QA76.73.C15.Q55.

Source Code:

• i4mat_floyd.m finds the shortest I4 distances between pairs of nodes in a directed graph.
• i4mat_print.m prints an I4MAT.
• i4mat_print_some.m prints some of an I4MAT.
• r8mat_floyd.m finds the shortest R8 distances between pairs of nodes in a directed graph.
• r8mat_print.m prints an R8MAT.
• r8mat_print_some.m prints some of an R8MAT.
• s_len_trim.m returns the length of a string to the last nonblank.
• timestamp.m prints the current YMDHMS date as a time stamp.

Examples and Tests:

• floyd_test.m, a sample calling program.
• floyd_test01.m, tests I4MAT_FLOYD.
• floyd_test02.m, tests R8MAT_FLOYD.
• floyd_test03.m, tests I4MAT_FLOYD on matrices of increasing size, to get timing information.
• floyd_test_output.txt, the output file.

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