Commit 323e99a1 authored by Jerome Mariette's avatar Jerome Mariette
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#
# Copyright (C) 2012 INRA
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
#
class Graph(object):
def __init__(self, graph_dict={}):
""" initializes a graph object """
self.__graph_dict = graph_dict
def vertices(self):
""" returns the vertices of a graph """
return list(self.__graph_dict.keys())
def edges(self):
""" returns the edges of a graph """
edges = []
for edge in self.__generate_edges():
edges.append(list(edge))
return edges
def add_vertex(self, vertex):
""" If the vertex "vertex" is not in
self.__graph_dict, a key "vertex" with an empty
list as a value is added to the dictionary.
Otherwise nothing has to be done.
"""
if vertex not in self.__graph_dict:
self.__graph_dict[vertex] = []
def add_edge(self, edge):
""" assumes that edge is of type set, tuple or list;
between two vertices can be multiple edges!
"""
edge = set(edge)
(vertex1, vertex2) = tuple(edge)
if vertex1 in self.__graph_dict:
self.__graph_dict[vertex1].append(vertex2)
else:
self.__graph_dict[vertex1] = [vertex2]
def __generate_edges(self):
""" A static method generating the edges of the
graph "graph". Edges are represented as sets
with one (a loop back to the vertex) or two
vertices
"""
edges = []
for vertex in self.__graph_dict:
for neighbour in self.__graph_dict[vertex]:
if {neighbour, vertex} not in edges:
edges.append({vertex, neighbour})
return edges
def __str__(self):
res = "vertices: "
for k in self.__graph_dict:
res += str(k) + " "
res += "\nedges: "
for edge in self.__generate_edges():
res += str(edge) + " "
return res
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