def dsatur(orig, g, trans, frat, col, silent=True):
satdeg = {}
ncols = {}
for v in g:
satdeg[v] = 0
ncols[v] = set()
def upd(v, coloring, colorstats, graph):
vcol = coloring[v]
for w in graph.neighbours(v):
if w in ncols and vcol not in ncols[w]:
ncols[w].add(vcol)
satdeg[w] += 1
def vchoice(uncolored, coloring, graph):
# First choice: some max deg vertex
if len(coloring) == 0:
maxv = None
maxdeg = -1
for v in graph:
d = graph.degree(v)
if d > maxdeg:
maxdeg = d
maxv = v
del satdeg[v]
del ncols[v]
return v
# Now choose vertex that sees a maximum num of colors
# Todo: us a priority queue here.
res = maxsat = -1
for v in satdeg:
if satdeg[v] > maxsat:
maxsat = satdeg[v]
res = v
del satdeg[res]
del ncols[res]
return res
return color_by_ordering(g.undirected(), vchoice, next_free_color, upd)
def min_deg(orig, g, trans, frat, col, silent=True):
undir_g = g.undirected()
degBuckets = []
degrees = {} # Keep track of remaining degree
maxdegree = 0
for v in g:
d = undir_g.degree(v)
if d >= len(degBuckets):
degBuckets.extend([set() for x in range(len(degBuckets), d + 1)])
degBuckets[d].add(v)
degrees[v] = d
maxdegree = max(maxdegree, d)
for d in xrange(0, maxdegree+1):
if d >= len(degBuckets):
degBuckets.extend([set() for x in range(len(degBuckets), d + 1)])
def vchoice(uncolored, coloring, graph):
mindeg = 0
while len(degBuckets[mindeg]) == 0:
mindeg += 1
v = iter(degBuckets[mindeg]).next() # Just get any
degBuckets[mindeg].remove(v)
# Update neighbours
for w in graph.neighbours(v):
if w not in degrees or w == v:
continue # Was already processed
deg = degrees[w]
degBuckets[deg].remove(w)
degBuckets[deg-1].add(w)
degrees[w] -= 1
del degrees[v]
return v
return color_by_ordering(undir_g, vchoice, next_free_color)
def min_deg(orig, g, trans, frat, col, silent=True):
undir_g = g.undirected()
degBuckets = []
degrees = {} # Keep track of remaining degree
maxdegree = 0
for v in g:
d = undir_g.degree(v)
if d >= len(degBuckets):
degBuckets.extend([set() for x in range(len(degBuckets), d + 1)])
degBuckets[d].add(v)
degrees[v] = d
maxdegree = max(maxdegree, d)
for d in xrange(0, maxdegree + 1):
if d >= len(degBuckets):
degBuckets.extend([set() for x in range(len(degBuckets), d + 1)])
def vchoice(uncolored, coloring, graph):
mindeg = 0
while len(degBuckets[mindeg]) == 0:
mindeg += 1
v = iter(degBuckets[mindeg]).next() # Just get any
degBuckets[mindeg].remove(v)
# Update neighbours
for w in graph.neighbours(v):
if w not in degrees or w == v:
continue # Was already processed
deg = degrees[w]
degBuckets[deg].remove(w)
degBuckets[deg - 1].add(w)
degrees[w] -= 1
del degrees[v]
return v
return color_by_ordering(undir_g, vchoice, next_free_color)
