def merge_colors(graph, cols, p):
# order the coloring by frequency
ordered_col = cols.normalize()
# create lookup of vertices by color
color_sets = [set() for i in ordered_col.colors()]
for v in graph:
color_sets[ordered_col[v]].add(v)
num_colors = len(ordered_col)
echo(len(ordered_col))
# iterate through all colors
for c1 in range(num_colors):
# vertices with color c1
c1_vertices = color_sets[c1]
# skip ahead if we've already merged c1 with another color
if len(c1_vertices) == 0:
continue
echo("\n", c1, c1_vertices)
# otherwise iterate through all colors with fewer vertices
for c2 in range(c1+1,num_colors):
# vertices with color c2
c2_vertices = color_sets[c2]
# skip ahead if we've already merged c2 with another color
if len(c2_vertices) == 0:
continue
echo("\t", c2, c2_vertices)
# check whether c1 and c2 together form an independent set
if independent_colors(graph, c1_vertices, c2_vertices):
# temporarily color all c2 vertices with c1
recolor(ordered_col, c2_vertices, c1)
echo("\t\t",list(ordered_col[v] for v in c2_vertices))
#assert same_color(ordered_col, c2_vertices, c1)
#assert same_color(ordered_col, c1_vertices, c1)
# check if merge would be p-centered
is_p_centered,_ = check_tree_depth(graph, graph, ordered_col, p)
echo("\t\t",is_p_centered, _)
if is_p_centered:
# merge the vertices of c2 into c1
c1_vertices |= c2_vertices
c2_vertices.clear()
echo("\t\tNew c1:", c1_vertices)
else:
# restore the c2 vertices to their original color
echo("\t\tNot",p+1,"centered")
recolor(ordered_col, c2_vertices, c2)
#assert same_color(ordered_col, c2_vertices, c2)
else:
echo("\t\tDependent")
# ensure the final coloring has no unused colors
c_idx = 0
final_coloring = Coloring()
for v_set in color_sets:
echo(v_set)
if len(v_set) > 0:
recolor(final_coloring, v_set, c_idx)
c_idx += 1
else:
echo("skipped")
return final_coloring
parser.add_argument("colors", help="A vertex coloring file")
parser.add_argument("p", help="the number of color classes that yield "
"low-td components, i.e. the coloring is (p+1)-"
"centered coloring",
type=int)
args = parser.parse_args()
graph = load_graph(args.graph)
remove_loops(graph)
cols = load_coloring(args.colors)
p = args.p
print "Loaded {0} and coloring {1} ({2} colors)".format(args.graph,
args.colors,
len(cols))
res = cols.is_proper(graph) and check_tree_depth(graph, graph, cols, p)
print "{0}-centered coloring: {1}".format(p+1, res)
print ""
optcols = merge_colors(graph, cols, p)
size = len(optcols)
print "Best coloring found has size", size
print "Paranoia-check: ",
is_p_centered,_ = check_tree_depth(graph, graph, optcols, p)
if optcols.is_proper(graph) and is_p_centered:
print "Yes! All is good!"
write_coloring(optcols, args.colors + ".opt")
else:
print "Oh nooooooo!"
