digraph_adj

digraph_adj, an Octave code which carries out operations on abstract digraphs, a kind of graph with directed edges, described by an adjacency matrix.

Licensing:

The information on this web page is distributed under the MIT license.

Languages:

digraph_adj is available in a Fortran90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:

digraph_adj_test

graph_adj, an Octave code which carries out operations on abstract graphs, with undirected edges, represented by an adjacency matrix. Operations include breadth-first search, the computation of a minimum spanning tree, an Euler or Hamilton circuit, blocks, chromatic polynomial, or transitive closure.

pagerank, an Octave code which uses the eigenvalue (power method) and surfer (Markov Chain Monte Carlo MCMC) approaches to ranking web pages.

test_matrix, an Octave code which defines test matrices for which the condition number, determinant, eigenvalues, eigenvectors, inverse, null vectors, P*L*U factorization or linear system solution are known. Examples include the Fibonacci, Hilbert, Redheffer, Vandermonde, Wathen and Wilkinson matrices.

web_matrix, an Octave code which stores sample matrices describing a web page network. These matrices are typically very sparse, and the examples here are stored using the sparse triplet (ST) format. They can be used to demonstrate pagerank and other graph algorithms.

Source Code:

• abc_inc.m, the incidence matrix for a 3 node digraph.
• abcd_inc.m, the incidence matrix for a 4 node digraph.
• five_inc.m, the incidence matrix for a 5 node digraph.
• inc_to_google.m, constructs the Google matrix from an incidence matrix.
• inc_to_transition.m, constructs the transition matrix from an incidence matrix.
• moler_inc.m, the incidence matrix for a 6 node digraph.
• sauer_inc.m, the incidence matrix for a 15 node digraph.