def critical(G, logger=None, dense=False):
'''
a method that finds if the graph is critical
Parameters:
G: the graph to check (networkx)
logger: an optional logger
dense: True if the graph is quite dense (boolean)
Returns:
K: how many colors the graphs need to be colored (int),
None if the graph is not critical
'''
if dense:
coloring = color
else:
coloring = dense_color_wrapper
is_critical = True
nodes = G.nodes()
index = 0
chromatic = len(coloring(G))
while is_critical and index < len(nodes):
g = G.copy()
g.remove_node(nodes[index])
check = len(coloring(g))
if check != (chromatic -1):
if logger is not None:
logger.info(index)
logger.info("G is not critical")
is_critical = False
index += 1
K = None
if is_critical:
K = chromatic
return K
def color(G, logger=None, dense=False):
'''
a function to color the G with least amount of colors
IT MAY TAKE AWHILE
Parameters:
G: the graph to color (networkx)
logger: an optional logger argument
dense: True if the graph is dense (boolean)
Retuns:
result: a list of colors where each color is a list of nodes
E.G [[0],[1],[2]] for K3
'''
if not dense:
result = coloring(G, logger=logger)
else:
result = dense_color_wrapper(G, logger=logger)
return result
