def from_sparse6(G, g6_string):
r"""
Fill ``G`` with the data of a sparse6 string.
INPUT:
- ``G`` -- a graph
- ``g6_string`` -- a sparse6 string
EXAMPLE::
sage: from sage.graphs.graph_input import from_sparse6
sage: g = Graph()
sage: from_sparse6(g, ':I`ES@obGkqegW~')
sage: g.is_isomorphic(graphs.PetersenGraph())
True
"""
from generic_graph_pyx import length_and_string_from_graph6, int_to_binary_string
from math import ceil, floor
from sage.misc.functional import log
n = g6_string.find('\n')
if n == -1:
n = len(g6_string)
s = g6_string[:n]
n, s = length_and_string_from_graph6(s[1:])
if n == 0:
edges = []
else:
k = int(ceil(log(n, 2)))
ords = [ord(i) for i in s]
if any(o > 126 or o < 63 for o in ords):
raise RuntimeError(
"The string seems corrupt: valid characters are \n" +
''.join([chr(i) for i in xrange(63, 127)]))
bits = ''.join([int_to_binary_string(o - 63).zfill(6) for o in ords])
b = []
x = []
for i in xrange(int(floor(len(bits) / (k + 1)))):
b.append(int(bits[(k + 1) * i:(k + 1) * i + 1], 2))
x.append(int(bits[(k + 1) * i + 1:(k + 1) * i + k + 1], 2))
v = 0
edges = []
for i in xrange(len(b)):
if b[i] == 1:
v += 1
if x[i] > v:
v = x[i]
else:
if v < n:
edges.append((x[i], v))
G.add_vertices(range(n))
G.add_edges(edges)
def from_sparse6(G, g6_string):
r"""
Fill ``G`` with the data of a sparse6 string.
INPUT:
- ``G`` -- a graph
- ``g6_string`` -- a sparse6 string
EXAMPLE::
sage: from sage.graphs.graph_input import from_sparse6
sage: g = Graph()
sage: from_sparse6(g, ':I`ES@obGkqegW~')
sage: g.is_isomorphic(graphs.PetersenGraph())
True
"""
from generic_graph_pyx import length_and_string_from_graph6, int_to_binary_string
from math import ceil, floor
from sage.misc.functional import log
n = g6_string.find('\n')
if n == -1:
n = len(g6_string)
s = g6_string[:n]
n, s = length_and_string_from_graph6(s[1:])
if n == 0:
edges = []
else:
k = int(ceil(log(n,2)))
ords = [ord(i) for i in s]
if any(o > 126 or o < 63 for o in ords):
raise RuntimeError("The string seems corrupt: valid characters are \n" + ''.join([chr(i) for i in xrange(63,127)]))
bits = ''.join([int_to_binary_string(o-63).zfill(6) for o in ords])
b = []
x = []
for i in xrange(int(floor(len(bits)/(k+1)))):
b.append(int(bits[(k+1)*i:(k+1)*i+1],2))
x.append(int(bits[(k+1)*i+1:(k+1)*i+k+1],2))
v = 0
edges = []
for i in xrange(len(b)):
if b[i] == 1:
v += 1
if x[i] > v:
v = x[i]
else:
if v < n:
edges.append((x[i],v))
G.add_vertices(range(n))
G.add_edges(edges)
def from_graph6(G, g6_string):
r"""
Fill ``G`` with the data of a graph6 string.
INPUT:
- ``G`` -- a graph
- ``g6_string`` -- a graph6 string
EXAMPLE::
sage: from sage.graphs.graph_input import from_graph6
sage: g = Graph()
sage: from_graph6(g, 'IheA@GUAo')
sage: g.is_isomorphic(graphs.PetersenGraph())
True
"""
from generic_graph_pyx import length_and_string_from_graph6, binary_string_from_graph6
if not isinstance(g6_string, str):
raise ValueError(
'If input format is graph6, then g6_string must be a string.')
n = g6_string.find('\n')
if n == -1:
n = len(g6_string)
ss = g6_string[:n]
n, s = length_and_string_from_graph6(ss)
m = binary_string_from_graph6(s, n)
expected = n * (n - 1) / 2 + (6 - n * (n - 1) / 2) % 6
if len(m) > expected:
raise RuntimeError(
"The string (%s) seems corrupt: for n = %d, the string is too long."
% (ss, n))
elif len(m) < expected:
raise RuntimeError(
"The string (%s) seems corrupt: for n = %d, the string is too short."
% (ss, n))
G.add_vertices(range(n))
k = 0
for i in xrange(n):
for j in xrange(i):
if m[k] == '1':
G._backend.add_edge(i, j, None, False)
k += 1
def from_dig6(G, dig6_string):
r"""
Fill ``G`` with the data of a dig6 string.
INPUT:
- ``G`` -- a graph
- ``dig6_string`` -- a dig6 string
EXAMPLE::
sage: from sage.graphs.graph_input import from_dig6
sage: g = DiGraph()
sage: from_dig6(g, digraphs.Circuit(10).dig6_string())
sage: g.is_isomorphic(digraphs.Circuit(10))
True
"""
from generic_graph_pyx import length_and_string_from_graph6, binary_string_from_dig6
if not isinstance(dig6_string, str):
raise ValueError(
'If input format is dig6, then dig6_string must be a string.')
n = dig6_string.find('\n')
if n == -1:
n = len(dig6_string)
ss = dig6_string[:n]
n, s = length_and_string_from_graph6(ss)
m = binary_string_from_dig6(s, n)
expected = n**2
if len(m) > expected:
raise RuntimeError(
"The string (%s) seems corrupt: for n = %d, the string is too long."
% (ss, n))
elif len(m) < expected:
raise RuntimeError(
"The string (%s) seems corrupt: for n = %d, the string is too short."
% (ss, n))
G.add_vertices(range(n))
k = 0
for i in xrange(n):
for j in xrange(n):
if m[k] == '1':
G._backend.add_edge(i, j, None, True)
k += 1
def from_graph6(G, g6_string):
r"""
Fill ``G`` with the data of a graph6 string.
INPUT:
- ``G`` -- a graph
- ``g6_string`` -- a graph6 string
EXAMPLE::
sage: from sage.graphs.graph_input import from_graph6
sage: g = Graph()
sage: from_graph6(g, 'IheA@GUAo')
sage: g.is_isomorphic(graphs.PetersenGraph())
True
"""
from generic_graph_pyx import length_and_string_from_graph6, binary_string_from_graph6
if not isinstance(g6_string, str):
raise ValueError('If input format is graph6, then g6_string must be a string.')
n = g6_string.find('\n')
if n == -1:
n = len(g6_string)
ss = g6_string[:n]
n, s = length_and_string_from_graph6(ss)
m = binary_string_from_graph6(s, n)
expected = n*(n-1)/2 + (6 - n*(n-1)/2)%6
if len(m) > expected:
raise RuntimeError("The string (%s) seems corrupt: for n = %d, the string is too long."%(ss,n))
elif len(m) < expected:
raise RuntimeError("The string (%s) seems corrupt: for n = %d, the string is too short."%(ss,n))
G.add_vertices(range(n))
k = 0
for i in xrange(n):
for j in xrange(i):
if m[k] == '1':
G._backend.add_edge(i, j, None, False)
k += 1
def from_dig6(G, dig6_string):
r"""
Fill ``G`` with the data of a dig6 string.
INPUT:
- ``G`` -- a graph
- ``dig6_string`` -- a dig6 string
EXAMPLE::
sage: from sage.graphs.graph_input import from_dig6
sage: g = DiGraph()
sage: from_dig6(g, digraphs.Circuit(10).dig6_string())
sage: g.is_isomorphic(digraphs.Circuit(10))
True
"""
from generic_graph_pyx import length_and_string_from_graph6, binary_string_from_dig6
if not isinstance(dig6_string, str):
raise ValueError('If input format is dig6, then dig6_string must be a string.')
n = dig6_string.find('\n')
if n == -1:
n = len(dig6_string)
ss = dig6_string[:n]
n, s = length_and_string_from_graph6(ss)
m = binary_string_from_dig6(s, n)
expected = n**2
if len(m) > expected:
raise RuntimeError("The string (%s) seems corrupt: for n = %d, the string is too long."%(ss,n))
elif len(m) < expected:
raise RuntimeError("The string (%s) seems corrupt: for n = %d, the string is too short."%(ss,n))
G.add_vertices(range(n))
k = 0
for i in xrange(n):
for j in xrange(n):
if m[k] == '1':
G._backend.add_edge(i, j, None, True)
k += 1
