def add_node_attrs_rhs(self, n, attrs):
"""Add attrs to a node in the rhs."""
if n not in self.rhs.nodes():
raise RuleError(
"Node %s does not exist in the right "
"hand side of the rule" % n)
primitives.add_node_attrs(self.rhs, n, attrs)
def relation_to_span(g1,
g2,
relation,
edges=False,
attrs=False,
directed=True):
"""Convert a relation to a span."""
if directed:
new_graph = nx.DiGraph()
else:
new_graph = nx.Graph()
left_h = dict()
right_h = dict()
for a, b in relation:
new_node = str(a) + "_" + str(b)
new_graph.add_node(new_node)
if attrs:
common_attrs = attrs_intersection(g1.node[a], g2.node[b])
add_node_attrs(new_graph, new_node, common_attrs)
left_h[new_node] = a
right_h[new_node] = b
for n1 in new_graph.nodes():
for n2 in new_graph.nodes():
if (left_h[n1], left_h[n2]) in g1.edges() and\
(right_h[n1], right_h[n2]) in g2.edges():
new_graph.add_edge(n1, n2)
common_attrs = attrs_intersection(
g1.edge[left_h[n1]][left_h[n2]],
g2.edge[right_h[n1]][right_h[n2]],
)
add_edge_attrs(new_graph, n1, n2, common_attrs)
return (new_graph, left_h, right_h)
def _add_node_attrs_lhs(self, n, attrs):
if n not in self.lhs.nodes():
raise RuleError(
"Node '%s' does not exist in the lhs "
"of the rule" % n)
primitives.add_node_attrs(self.lhs, n, attrs)
p_nodes = keys_by_value(self.p_rhs, n)
for p_node in p_nodes:
primitives.add_node_attrs(self.p, p_node, attrs)
def _propagate_values(hie, id, parent, mapping):
anc = hie.get_ancestors(parent)
graph = hie.node[id].graph
parent_gr = hie.node[parent].graph
for (anc_id, anc_typ) in anc.items():
anc_gr = hie.node[anc_id].graph
for node in mapping:
if mapping[node] in anc_typ:
prim.add_node_attrs(anc_gr, anc_typ[mapping[node]],
graph.node[node])
for node in mapping:
prim.add_node_attrs(parent_gr, mapping[node], graph.node[node])
def _propagate_values(hie, id, parent, mapping):
anc = hie.get_ancestors(parent)
graph = hie.node[id].graph
parent_gr = hie.node[parent].graph
for (anc_id, anc_typ) in anc.items():
anc_gr = hie.node[anc_id].graph
for node in mapping:
if mapping[node] in anc_typ:
prim.add_node_attrs(anc_gr, anc_typ[mapping[node]],
graph.node[node])
for node in mapping:
prim.add_node_attrs(parent_gr, mapping[node],
graph.node[node])
def add_node_attrs(self, n, attrs):
"""Add node attributes to a node in the graph."""
if n not in self.lhs.nodes():
raise RuleError(
"Node '%s' does not exist in the left "
"hand side of the rule" % n)
p_keys = keys_by_value(self.p_lhs, n)
if len(p_keys) == 0:
raise RuleError(
"Node '%s' is being removed by the rule, "
"cannot add attributes" % n)
for k in p_keys:
primitives.add_node_attrs(self.rhs, self.p_rhs[k], attrs)
return
def pushout_from_relation(g1, g2, relation, inplace=False):
"""Find the pushout from a relation."""
left_dict = left_relation_dict(relation)
right_dict = right_relation_dict(relation)
if inplace is True:
g12 = g1
else:
g12 = copy.deepcopy(g1)
g1_g12 = id_of(g12.nodes())
g2_g12 = dict()
for node in g1.nodes():
if node in left_dict.keys():
for g2_node in left_dict[node]:
g2_g12[g2_node] = node
for node in g2.nodes():
if node not in right_dict.keys():
add_node(g12, node, g2.node[node])
g2_g12[node] = node
elif len(right_dict[node]) == 1:
node_attrs_diff = dict_sub(
g2.node[node],
g1.node[list(right_dict[node])[0]])
add_node_attrs(
g12, list(right_dict[node])[0], node_attrs_diff)
elif len(right_dict[node]) > 1:
new_name = merge_nodes(g12, right_dict[node])
for g1_node in right_dict[node]:
g1_g12[g1_node] = new_name
g2_g12[node] = new_name
node_attrs_diff = dict_sub(
g2.node[node],
g12.node[new_name])
add_node_attrs(g12, new_name, node_attrs_diff)
for u, v in g2.edges():
if (g2_g12[u], g2_g12[v]) not in g12.edges():
add_edge(g12, g2_g12[u], g2_g12[v], get_edge(g2, u, v))
else:
edge_attrs_diff = dict_sub(
g2.edge[u][v],
g12.edge[g2_g12[u]][g2_g12[v]])
add_edge_attrs(g12, g2_g12[u], g2_g12[v], edge_attrs_diff)
return (g12, g1_g12, g2_g12)
def remove_attributes(hie, g_id, parent, node, json_attrs):
"""remove the attributes from json_attrs from the node"""
attrs = prim.json_dict_to_attrs(json_attrs)
if isinstance(hie.node[g_id], GraphNode):
lhs = nx.DiGraph()
lhs.add_node(node)
add_node_attrs(lhs, node, attrs)
ppp = nx.DiGraph()
ppp.add_node(node)
rhs = nx.DiGraph()
rhs.add_node(node)
rule = Rule(ppp, lhs, rhs)
_rewrite(hie, g_id, rule, {node: node})
elif isinstance(hie.node[g_id], RuleNode):
hie.node[g_id].rule.remove_node_attrs_rhs(node, attrs)
else:
raise ValueError("node is neither a rule nor a graph")
def add_attributes(hie, g_id, parent, node, json_attrs):
"""add the attributes from the json_attrs dict to a node"""
attrs = prim.json_dict_to_attrs(json_attrs)
if isinstance(hie.node[g_id], GraphNode):
for typing in hie.successors(g_id):
mapping = hie.edge[g_id][typing].mapping
if node in mapping:
parent_attrs = hie.node[typing].graph.node[mapping[node]]
if not valid_attributes(attrs, parent_attrs):
raise ValueError("Attributes not in node {} of {}".format(
mapping[node], typing))
prim.add_node_attrs(hie.node[g_id].graph, node, attrs)
elif isinstance(hie.node[g_id], RuleNode):
hie.node[g_id].rule.add_node_attrs_rhs(node, attrs)
else:
raise ValueError("node is neither a rule nor a graph")
def remove_attributes(hie, g_id, parent, node, json_attrs):
"""remove the attributes from json_attrs from the node"""
attrs = prim.json_dict_to_attrs(json_attrs)
if isinstance(hie.node[g_id], GraphNode):
lhs = nx.DiGraph()
lhs.add_node(node)
add_node_attrs(lhs, node, attrs)
ppp = nx.DiGraph()
ppp.add_node(node)
rhs = nx.DiGraph()
rhs.add_node(node)
rule = Rule(ppp, lhs, rhs)
_rewrite(hie, g_id, rule, {node: node})
elif isinstance(hie.node[g_id], RuleNode):
hie.node[g_id].rule.remove_node_attrs_rhs(node, attrs)
else:
raise ValueError("node is neither a rule nor a graph")
def add_attributes(hie, g_id, parent, node, json_attrs):
"""add the attributes from the json_attrs dict to a node"""
attrs = prim.json_dict_to_attrs(json_attrs)
if isinstance(hie.node[g_id], GraphNode):
for typing in hie.successors(g_id):
mapping = hie.edge[g_id][typing].mapping
if node in mapping:
parent_attrs = hie.node[typing].graph.node[mapping[node]]
if not valid_attributes(attrs, parent_attrs):
raise ValueError("Attributes not in node {} of {}"
.format(mapping[node], typing))
prim.add_node_attrs(hie.node[g_id].graph, node, attrs)
elif isinstance(hie.node[g_id], RuleNode):
hie.node[g_id].rule.add_node_attrs_rhs(node, attrs)
else:
raise ValueError("node is neither a rule nor a graph")
def inject_add_node_attrs(self, n, attrs):
"""Inject addition of node attributes by the rule.
First, tries to find a node with the id `n` in the
left-hand side, injects its attrs add to all the `rhs` nodes
related to it through l<-p->r, if found,
otherwise, tries to find the corresponding node in
the preserved part and adds attrs to the node to which `n`
maps in p->r, if it is not found in `p`, tries to find it in
the `rhs` (it helps us to implement injection
of the node attrs add to only one of the clone nodes, or to new nodes,
or to merged nodes).
Parameters
----------
n1 : hashable
Id of an edge's source node in `lhs`, `p` or `rhs`.
n2 : hashable
Id of an edge's target node in `lhs`, `p` or `rhs`.
attrs : dict
Dictionary with attrs to add
Raises
------
RuleError
If node `n` does not exist in the rhs of the rule
"""
if n not in self.lhs.nodes() + self.p.nodes() + self.rhs.nodes():
raise RuleError(
"Node '%s' exists in neither lhs, nor p, nor rhs of the rule" %
n)
r_nodes = set()
if n in self.lhs.nodes():
p_keys = keys_by_value(self.p_lhs, n)
for p in p_keys:
r_nodes.add(self.p_rhs[p])
elif n in self.p.nodes():
r_nodes.add(self.p_rhs[n])
elif n in self.rhs.nodes():
r_nodes.add(n)
for r in r_nodes:
primitives.add_node_attrs(self.rhs, r, attrs)
return
def pushout_from_relation(g1, g2, relation, inplace=False):
"""Find the pushout from a relation."""
left_dict = left_relation_dict(relation)
right_dict = right_relation_dict(relation)
if inplace is True:
g12 = g1
else:
g12 = copy.deepcopy(g1)
g1_g12 = id_of(g12.nodes())
g2_g12 = dict()
for node in g1.nodes():
if node in left_dict.keys():
for g2_node in left_dict[node]:
g2_g12[g2_node] = node
for node in g2.nodes():
if node not in right_dict.keys():
add_node(g12, node, g2.node[node])
g2_g12[node] = node
elif len(right_dict[node]) == 1:
node_attrs_diff = dict_sub(g2.node[node],
g1.node[list(right_dict[node])[0]])
add_node_attrs(g12, list(right_dict[node])[0], node_attrs_diff)
elif len(right_dict[node]) > 1:
new_name = merge_nodes(g12, right_dict[node])
for g1_node in right_dict[node]:
g1_g12[g1_node] = new_name
g2_g12[node] = new_name
node_attrs_diff = dict_sub(g2.node[node], g12.node[new_name])
add_node_attrs(g12, new_name, node_attrs_diff)
for u, v in g2.edges():
if (g2_g12[u], g2_g12[v]) not in g12.edges():
add_edge(g12, g2_g12[u], g2_g12[v], get_edge(g2, u, v))
else:
edge_attrs_diff = dict_sub(g2.edge[u][v],
g12.edge[g2_g12[u]][g2_g12[v]])
add_edge_attrs(g12, g2_g12[u], g2_g12[v], edge_attrs_diff)
return (g12, g1_g12, g2_g12)
def relation_to_span(g1, g2, relation, edges=False, attrs=False, directed=True):
"""Convert a relation to a span."""
if directed:
new_graph = nx.DiGraph()
else:
new_graph = nx.Graph()
left_h = dict()
right_h = dict()
for a, b in relation:
new_node = str(a) + "_" + str(b)
new_graph.add_node(new_node)
if attrs:
common_attrs = attrs_intersection(
g1.node[a],
g2.node[b]
)
add_node_attrs(new_graph, new_node, common_attrs)
left_h[new_node] = a
right_h[new_node] = b
for n1 in new_graph.nodes():
for n2 in new_graph.nodes():
if (left_h[n1], left_h[n2]) in g1.edges() and\
(right_h[n1], right_h[n2]) in g2.edges():
new_graph.add_edge(n1, n2)
common_attrs = attrs_intersection(
g1.edge[left_h[n1]][left_h[n2]],
g2.edge[right_h[n1]][right_h[n2]],
)
add_edge_attrs(
new_graph,
n1, n2,
common_attrs
)
return (new_graph, left_h, right_h)
def pushout(a, b, c, a_b, a_c, inplace=False):
"""Find the pushour of the span b <- a -> c."""
check_homomorphism(a, b, a_b)
check_homomorphism(a, c, a_c)
if inplace is True:
d = b
else:
d = copy.deepcopy(b)
b_d = id_of(b.nodes())
c_d = dict()
# Add/merge nodes
for c_n in c.nodes():
a_keys = keys_by_value(a_c, c_n)
# Add nodes
if len(a_keys) == 0:
add_node(d, c_n, c.node[c_n])
c_d[c_n] = c_n
# Keep nodes
elif len(a_keys) == 1:
c_d[a_c[a_keys[0]]] = a_b[a_keys[0]]
# Merge nodes
else:
nodes_to_merge = []
for k in a_keys:
nodes_to_merge.append(a_b[k])
new_name = merge_nodes(d, nodes_to_merge)
c_d[c_n] = new_name
for node in nodes_to_merge:
b_d[node] = new_name
# Add edges
for (n1, n2) in c.edges():
if b.is_directed():
if (c_d[n1], c_d[n2]) not in d.edges():
add_edge(
d, c_d[n1], c_d[n2],
get_edge(c, n1, n2))
else:
if (c_d[n1], c_d[n2]) not in d.edges() and\
(c_d[n2], c_d[n1]) not in d.edges():
add_edge(
d, c_d[n1], c_d[n2],
get_edge(c, n1, n2)
)
# Add node attrs
for c_n in c.nodes():
a_keys = keys_by_value(a_c, c_n)
# Add attributes to the nodes which stayed invariant
if len(a_keys) == 1:
attrs_to_add = dict_sub(
c.node[c_n],
a.node[a_keys[0]]
)
add_node_attrs(d, c_d[c_n], attrs_to_add)
# Add attributes to the nodes which were merged
elif len(a_keys) > 1:
merged_attrs = {}
for k in a_keys:
merged_attrs = merge_attributes(
merged_attrs,
a.node[k]
)
attrs_to_add = dict_sub(c.node[c_n], merged_attrs)
add_node_attrs(d, c_d[c_n], attrs_to_add)
# Add edge attrs
for (n1, n2) in c.edges():
d_n1 = c_d[n1]
d_n2 = c_d[n2]
if d.is_directed():
attrs_to_add = dict_sub(
get_edge(c, n1, n2),
get_edge(d, d_n1, d_n2)
)
add_edge_attrs(
d, c_d[n1], c_d[n2],
attrs_to_add
)
else:
attrs_to_add = dict_sub(
get_edge(c, n1, n2),
get_edge(d, d_n1, d_n2)
)
add_edge_attrs(
d, c_d[n1], c_d[n2],
attrs_to_add
)
return (d, b_d, c_d)
def pushout(a, b, c, a_b, a_c, inplace=False):
"""Find the pushour of the span b <- a -> c."""
check_homomorphism(a, b, a_b)
check_homomorphism(a, c, a_c)
if inplace is True:
d = b
else:
d = copy.deepcopy(b)
b_d = id_of(b.nodes())
c_d = dict()
# Add/merge nodes
for c_n in c.nodes():
a_keys = keys_by_value(a_c, c_n)
# Add nodes
if len(a_keys) == 0:
add_node(d, c_n, c.node[c_n])
c_d[c_n] = c_n
# Keep nodes
elif len(a_keys) == 1:
c_d[a_c[a_keys[0]]] = a_b[a_keys[0]]
# Merge nodes
else:
nodes_to_merge = []
for k in a_keys:
nodes_to_merge.append(a_b[k])
new_name = merge_nodes(d, nodes_to_merge)
c_d[c_n] = new_name
for node in nodes_to_merge:
b_d[node] = new_name
# Add edges
for (n1, n2) in c.edges():
if b.is_directed():
if (c_d[n1], c_d[n2]) not in d.edges():
add_edge(d, c_d[n1], c_d[n2], get_edge(c, n1, n2))
else:
if (c_d[n1], c_d[n2]) not in d.edges() and\
(c_d[n2], c_d[n1]) not in d.edges():
add_edge(d, c_d[n1], c_d[n2], get_edge(c, n1, n2))
# Add node attrs
for c_n in c.nodes():
a_keys = keys_by_value(a_c, c_n)
# Add attributes to the nodes which stayed invariant
if len(a_keys) == 1:
attrs_to_add = dict_sub(c.node[c_n], a.node[a_keys[0]])
add_node_attrs(d, c_d[c_n], attrs_to_add)
# Add attributes to the nodes which were merged
elif len(a_keys) > 1:
merged_attrs = {}
for k in a_keys:
merged_attrs = merge_attributes(merged_attrs, a.node[k])
attrs_to_add = dict_sub(c.node[c_n], merged_attrs)
add_node_attrs(d, c_d[c_n], attrs_to_add)
# Add edge attrs
for (n1, n2) in c.edges():
d_n1 = c_d[n1]
d_n2 = c_d[n2]
if d.is_directed():
attrs_to_add = dict_sub(get_edge(c, n1, n2),
get_edge(d, d_n1, d_n2))
add_edge_attrs(d, c_d[n1], c_d[n2], attrs_to_add)
else:
attrs_to_add = dict_sub(get_edge(c, n1, n2),
get_edge(d, d_n1, d_n2))
add_edge_attrs(d, c_d[n1], c_d[n2], attrs_to_add)
return (d, b_d, c_d)