def is_graphic(sequence):
"""Return whether or not the input sequence is graphic.
A sequence of positive integers is said to be a *graphic sequence* if there
exist a graph whose degree sequence is equal to the input sequence, up to
ordering.
Parameters
----------
sequence : list, iterable
A list or other iterable container of integers.
Returns
-------
bool
True if the input sequence is graphic. False otherwise.
"""
hh = gp.HavelHakimi(sequence)
return hh.is_graphic()
def havel_hakimi_process(G):
"""Return an instance of the HavelHakimi class initialized with the degree
sequence of the graph.
Parameters
----------
G : NetworkX graph
An undirected graph.
Returns
-------
object
An instance of the HavelHakimi class initialized with the degree
sequence of the graph.
See Also
--------
HavelHakimi
"""
return gp.HavelHakimi(degree_sequence(G))
def is_graphic(lSequence):
hh = gp.HavelHakimi(lSequence)
return hh.is_graphic()
def havel_hakimi_process(nxGraph):
return gp.HavelHakimi(degree_sequence(nxGraph))
def test_non_integer_values_raises_TypeError(self):
with pytest.raises(TypeError):
hh = gp.HavelHakimi([3, 3, 1.5, 1])
def test_non_iterable_raises_TypeError(self):
with pytest.raises(TypeError):
hh = gp.HavelHakimi(0)
def test_initial_sequence(self):
G = gp.complete_graph(4)
hh = gp.HavelHakimi(gp.degree_sequence(G))
assert hh.get_initial_sequence() == [3, 3, 3, 3]
def test_depth_of_complete_graph_is_order_minus_1(self):
for i in range(2, 12):
G = gp.complete_graph(i)
hh = gp.HavelHakimi(gp.degree_sequence(G))
assert hh.depth() == G.order() - 1
def test_elimination_sequence_of_complete_graph(self):
G = gp.complete_graph(4)
hh = gp.HavelHakimi(gp.degree_sequence(G))
e = [3, 2, 1, 0]
assert hh.get_elimination_sequence() == e
def test_process_of_compete_graph(self):
G = gp.complete_graph(4)
hh = gp.HavelHakimi(gp.degree_sequence(G))
p = [[3, 3, 3, 3], [2, 2, 2], [1, 1], [0]]
assert hh.get_process() == p
def test_sequence_of_zeros_is_graphic(self):
hh = gp.HavelHakimi([0, 0, 0, 0, 0])
assert hh.is_graphic() == True
def test_descending_sequence_of_integers_is_not_graphic(self):
hh = gp.HavelHakimi([5, 4, 3, 2, 1])
assert hh.is_graphic() == False
def test_havel_hakimi_with_integral_floats(self):
hh = gp.HavelHakimi([1.0, 1.0])
assert hh.residue() == 1