def iter_random_4regular_planar_graphs(N_low, N_top, G = None):
if G is None: G = octahedron()
else: G.is_planar(None, True) # asures an embedding
f_list = (phi_A, phi_B, phi_C, phi_F)
prob_f = (.25 , .25 , .25 , .25)
while G.order() < N_top:
f = probabilistic_choice(f_list, prob_f)
V = G.order()
G = f(G)
if V != G.order() and V > N_low:
yield G
def random_4regular_planar_graph(N, G = None):
if G is None: G = octahedron()
else: G.is_planar(None, True)
f_list = (phi_A, phi_B, phi_C, phi_F)
prob_f = (.80 , .05 , .10 , .05)
# prob_f = (.48 , .02 , .48 , .02)
# prob_f = (.25 , .25 , .25 , .25)
while G.order() < N:
f = probabilistic_choice(f_list, prob_f)
G = f(G)
if not G.is_planar(): raise RuntimeError("non-planar error ")
if not G.is_regular(4): raise RuntimeError("non-regular error ")
return G
