NAME

Graphs::Degree

VERSION

v0.1.0

SYNOPSIS

    use Graphs::Degree;

    # To use the module we need a graph in a hash of hashes:
    my $graph;

    $graph->{node1}->{node2} = undef;
    $graph->{node1}->{node3} = undef;
    $graph->{node2}->{node3} = undef;
    $graph->{node3}->{node1} = undef;
    
    # Then we call the module
    my $nodes = nodes_by_degree(
        {
            graph => $graph,
            rule  => "in",
            file  => "output.txt"
        }
    );

    say "Node with highest degree: $nodes->[0]->{name}, "
        "with indegree $nodes->[0]->{in} ", 
        "and outdegree $nodes->[0]->{out}";

    # You can also pass the arguments as a hash reference:

    my $options = {
        graph => $graph,
        rule  => "in",
        file  => "output.txt"
    };

    my $nodes = nodes_by_degree($options);


    # To iterate through the nodes:

    foreach my $node (@{ $nodes }) {
        say "Node $node->{name} has indegree $node->{in} and outdegree $node->{out}";
    }

----

You can use dot2degree.pl to sort the nodes of a graph in DOT (graphviz format).

    dot2degree.pl -i input.dot -o output.tbl -r RULE

    # You can use the rules 
        TOTAL
        IN
        OUT

Description

nodes_by_degree

This module only exports a function: nodes_by_degree()

This function does two things: it returns a data structure with the nodes of the graph ordered by in-degree, out-degree or total-degree; and it prints the ordered nodes to a file (if specified).

This function takes a hash reference with three elements described below (Arguments section).

It returns a list with the nodes sorted by the specified rule. The data structure is a list of hashes. Each element of the list points to a hash with three keys, "name", "in" and "out". To access the elements of the list:

    my $node_name      = $nodes->[$index]->{name} ;
    my $node_indegree  = $nodes->[$index]->{in}   ;
    my $node_outdegree = $nodes->[$index]->{out}  ;

ARGUMENTS

hash

A hash reference that describes a graph as follows:

    %hash = (
        parent1 => child1
                => child2

        parent2 => child3
                => child4

        ...
    )

rule

A rule to sort the nodes. Values: "TOTAL" or "IN" or "OUT" (case insensitive).

You can sort them by TOTAL degree (sum of in and out degree), IN degree or OUT degree. By default it will sort them by TOTAL degree.

file

A file to write the list.

If you don't specify one, it won't print the results.

Installation

    perl Makefile.PL
    make
    make install

Dependencies

If you want to use dot2degree.pl, you'll need the module Dot::Parser.

LICENSE

    COPYRIGHT 

    (C) 2015 - Sergio CASTILLO LARA

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.