def add_node(self, n):
if n in self:
return # already in tree
elif len(self.adj)==0:
Graph.add_node(self,n) # first node
else: # not allowed
raise NetworkXError(\
"adding single node %s not allowed in non-empty tree"%(n))
def add_node(self, n):
if n in self:
return # already in tree
elif len(self.adj) == 0:
Graph.add_node(self, n) # first node
else: # not allowed
raise NetworkXError(\
"adding single node %s not allowed in non-empty tree"%(n))
def delete_node(self, n):
try:
if len(self.adj[n]) == 1: # allowed for leaf node
Graph.delete_node(self, n)
else:
raise NetworkXError(
"deleting interior node %s not allowed in tree" % (n))
except KeyError: # NetworkXError if n not in self
raise NetworkXError("node %s not in graph" % n)
def delete_node(self, n):
try:
if len(self.adj[n])==1: # allowed for leaf node
Graph.delete_node(self,n)
else:
raise NetworkXError(
"deleting interior node %s not allowed in tree"%(n))
except KeyError: # NetworkXError if n not in self
raise NetworkXError("node %s not in graph"%n)
def delete_edge(self, u, v=None):
if v is None: (u,v)=u # no v given, assume u is an edge tuple
Graph.delete_edge(self,u,v)
# this will always break a tree into two trees
# put nodes connected to v in a new component
vnodes=component.node_connected_component(self,v)
for n in vnodes:
self.comp[n]=self.nc
self.nc+=1
def delete_edge(self, u, v=None):
if v is None: (u, v) = u # no v given, assume u is an edge tuple
Graph.delete_edge(self, u, v)
# this will always break a tree into two trees
# put nodes connected to v in a new component
vnodes = component.node_connected_component(self, v)
for n in vnodes:
self.comp[n] = self.nc
self.nc += 1
def add_edge(self, u, v=None):
if v is None: (u,v)=u # no v given, assume u is an edge tuple
if self.has_edge(u,v): return # no parallel edges allowed
elif u in self and v in self:
raise NetworkXError("adding edge %s-%s not allowed in tree"%(u,v))
elif u in self or v in self:
Graph.add_edge(self,u,v)
return
elif len(self.adj)==0: # first leaf
Graph.add_edge(self,u,v)
return
else:
raise NetworkXError("adding edge %s-%s not allowed in tree"%(u,v))
def delete_node(self, n):
# get neighbors first since this will remove all edges to them
neighbors = self.neighbors(n)
Graph.delete_node(self, n) # delete node and adjacent edges
del self.comp[n] # remove node from component dictionary
if len(neighbors) == 1: return # n was a leaf node
for nbr in neighbors:
# make new components of each nbr and connected graph
# FIXME this does more work then is necessary
# since nbrs of n could be in same conected component
# and then will get renumbered more than once
vnodes = component.node_connected_component(self, nbr)
for v in vnodes:
self.comp[v] = self.nc
self.nc += 1
def __init__(self,data=None,**kwds):
Graph.__init__(self,**kwds)
if data is not None:
try: # build a graph
G=Graph()
G=convert.from_whatever(data,create_using=G)
except:
raise NetworkXError, "Data %s is not a tree"%data
# check if it is a tree.
if G.order()==G.size()+1 and \
component.number_connected_components(G)==1:
self.adj=G.adj.copy()
del G
else:
raise NetworkXError, "Data %s is not a tree"%data
def add_edge(self, u, v=None):
if v is None: (u, v) = u # no v given, assume u is an edge tuple
if self.has_edge(u, v): return # no parallel edges allowed
elif u in self and v in self:
raise NetworkXError("adding edge %s-%s not allowed in tree" %
(u, v))
elif u in self or v in self:
Graph.add_edge(self, u, v)
return
elif len(self.adj) == 0: # first leaf
Graph.add_edge(self, u, v)
return
else:
raise NetworkXError("adding edge %s-%s not allowed in tree" %
(u, v))
def delete_node(self, n):
# get neighbors first since this will remove all edges to them
neighbors=self.neighbors(n)
Graph.delete_node(self,n) # delete node and adjacent edges
del self.comp[n] # remove node from component dictionary
if len(neighbors)==1: return # n was a leaf node
for nbr in neighbors:
# make new components of each nbr and connected graph
# FIXME this does more work then is necessary
# since nbrs of n could be in same conected component
# and then will get renumbered more than once
vnodes=component.node_connected_component(self,nbr)
for v in vnodes:
self.comp[v]=self.nc
self.nc+=1
def delete_edge(self, u, v=None):
if v is None: (u,v)=u
if self.degree(u)==1 or self.degree(v)==1: # leaf edge
Graph.delete_edge(self,u,v)
else: # interior edge
raise NetworkXError(\
"deleting interior edge %s-%s not allowed in tree"%(u,v))
if self.degree(u)==0: # OK to delete remaining isolated node
Graph.delete_node(self,u)
if self.degree(v)==0: # OK to delete remaining isolated node
Graph.delete_node(self,v)
def delete_edge(self, u, v=None):
if v is None: (u, v) = u
if self.degree(u) == 1 or self.degree(v) == 1: # leaf edge
Graph.delete_edge(self, u, v)
else: # interior edge
raise NetworkXError(\
"deleting interior edge %s-%s not allowed in tree"%(u,v))
if self.degree(u) == 0: # OK to delete remaining isolated node
Graph.delete_node(self, u)
if self.degree(v) == 0: # OK to delete remaining isolated node
Graph.delete_node(self, v)
def to_undirected(self):
"""Return an undirected representation of the digraph.
A new graph is returned with the same name and nodes and
with edge (u,v,data) if either (u,v,data) or (v,u,data)
is in the digraph. If both edges exist in digraph and
their edge data is different, only one edge is created
with an arbitrary choice of which edge data to use.
You must check and correct for this manually if desired.
"""
H = Graph()
H.name = self.name
H.add_nodes_from(self)
H.add_edges_from([(v, u, d)
for (u, v, d) in self.edges_iter(data=True)])
return H
def __init__(self, data=None, **kwds):
Graph.__init__(self, **kwds)
if data is not None:
try: # build a graph
G = Graph()
G = convert.from_whatever(data, create_using=G)
except:
raise NetworkXError, "Data %s is not a tree" % data
# check if it is a tree.
if G.order()==G.size()+1 and \
component.number_connected_components(G)==1:
self.adj = G.adj.copy()
del G
else:
raise NetworkXError, "Data %s is not a tree" % data
def to_undirected(self):
"""Return an undirected representation of the digraph.
A new graph is returned with the same name and nodes and
with edge (u,v,data) if either (u,v,data) or (v,u,data)
is in the digraph. If both edges exist in digraph and
their edge data is different, only one edge is created
with an arbitrary choice of which edge data to use.
You must check and correct for this manually if desired.
"""
H=Graph()
H.name=self.name
H.add_nodes_from(self)
H.add_edges_from([(v,u,d) for (u,v,d) in self.edges_iter(data=True)])
return H
def add_edge(self, u, v=None):
if v is None:
(u,v)=u # no v given, assume u is an edge tuple
if self.has_edge(u,v): # no parallel edges
return
elif u in self and v in self:
raise NetworkXError, "adding edge %s-%s not allowed in tree"%(u,v)
elif u in self:
Graph.add_edge(self,u,v)
self.par[v]=u
return
elif v in self:
Graph.add_edge(self,u,v)
self.par[u]=v
return
elif len(self.adj)==0: # first leaf
Graph.add_edge(self,u,v)
self.par[v]=u # u is v's parent
return
else:
raise NetworkXError, "adding edge %s-%s not allowed in tree"%(u,v)
def add_edge(self, u, v=None):
if v is None: (u,v)=u # no v given, assume u is an edge tuple
if self.has_edge(u,v): return # no parallel edges
if u in self: # u is in forest
if v in self: # v is in forest
if self.comp[u]==self.comp[v]: # same tree?
raise NetworkXError, \
"adding edge %s-%s not allowed in forest"%(u,v)
else: # join two trees
Graph.add_edge(self,u,v)
ucomp=self.comp[u]
# set component number of v tree to u tree
for n in component.node_connected_component(self,v):
self.comp[n]=ucomp
else: # add u-v to tree in component with u
Graph.add_edge(self,u,v)
self.comp[v]=self.comp[u]
else: # make new tree with only u-v
Graph.add_edge(self,u,v)
self.comp[u]=self.nc
self.comp[v]=self.nc
self.nc+=1
def add_edge(self, u, v=None):
if v is None: (u, v) = u # no v given, assume u is an edge tuple
if self.has_edge(u, v): return # no parallel edges
if u in self: # u is in forest
if v in self: # v is in forest
if self.comp[u] == self.comp[v]: # same tree?
raise NetworkXError, \
"adding edge %s-%s not allowed in forest"%(u,v)
else: # join two trees
Graph.add_edge(self, u, v)
ucomp = self.comp[u]
# set component number of v tree to u tree
for n in component.node_connected_component(self, v):
self.comp[n] = ucomp
else: # add u-v to tree in component with u
Graph.add_edge(self, u, v)
self.comp[v] = self.comp[u]
else: # make new tree with only u-v
Graph.add_edge(self, u, v)
self.comp[u] = self.nc
self.comp[v] = self.nc
self.nc += 1
def add_edge(self, u, v=None):
if v is None:
(u, v) = u # no v given, assume u is an edge tuple
if self.has_edge(u, v): # no parallel edges
return
elif u in self and v in self:
raise NetworkXError, "adding edge %s-%s not allowed in tree" % (u,
v)
elif u in self:
Graph.add_edge(self, u, v)
self.par[v] = u
return
elif v in self:
Graph.add_edge(self, u, v)
self.par[u] = v
return
elif len(self.adj) == 0: # first leaf
Graph.add_edge(self, u, v)
self.par[v] = u # u is v's parent
return
else:
raise NetworkXError, "adding edge %s-%s not allowed in tree" % (u,
v)
def add_node(self, n):
Graph.add_node(self,n)
# this is not called from add_edge so we must assign
# and component (else that is assigned in add_edge)
self.comp[n]=self.nc
self.nc+=1
def add_node(self, n):
Graph.add_node(self, n)
# this is not called from add_edge so we must assign
# and component (else that is assigned in add_edge)
self.comp[n] = self.nc
self.nc += 1
