def _add_sufficient_recall(cid: CID, dec1: str, dec2: str,
utility_node: str) -> None:
"""Add edges to a cid until `dec2` has sufficient recall of `dec1` (to optimize utility)
this is done by adding edges from non-collider nodes until recall is adequate
"""
if dec2 in cid._get_ancestors_of(dec1):
raise ValueError('{} is an ancestor of {}'.format(dec2, dec1))
cid2 = cid.copy()
cid2.add_edge('pi', dec1)
while cid2.is_active_trail('pi',
utility_node,
observed=cid.get_parents(dec2) + [dec2]):
path = find_active_path(cid2, 'pi', utility_node,
cid.get_parents(dec2) + [dec2])
if path is None:
raise Exception(
"couldn't find path even though there should be an active trail"
)
while True:
i = random.randrange(1, len(path) - 1)
# print('consider {}--{}--{}'.format(path[i-1], path[i], path[i+1]),end='')
collider = ((path[i - 1], path[i]) in cid2.edges) and (
(path[i + 1], path[i]) in cid2.edges)
if not collider:
if dec2 not in cid2._get_ancestors_of(path[i]):
# print('add {}->{}'.format(path[i], dec2), end=' ')
cid.add_edge(path[i], dec2)
cid2.add_edge(path[i], dec2)
break
def add_sufficient_recalls(cid: CID) -> None:
"""add edges to a cid until all decisions have sufficient recall of all prior decisions"""
for utility_node in cid.all_utility_nodes:
# decisions = cid._get_valid_order(cid.decision_nodes) # cannot be trusted...
for i, dec1 in enumerate(cid.all_decision_nodes):
for dec2 in cid.all_decision_nodes[i + 1:]:
if dec1 in cid._get_ancestors_of(dec2):
_add_sufficient_recall(cid, dec1, dec2, utility_node)
else:
_add_sufficient_recall(cid, dec2, dec1, utility_node)
def random_cid(n_all: int,
n_decisions: int,
n_utilities: int,
edge_density: float = 0.4,
add_sr_edges: bool = True,
add_cpds: bool = True,
seed: int = None) -> CID:
"""Generates a random Cid with the specified number of nodes and edges"""
all_names, decision_names, utility_names = get_node_names(
n_all, n_decisions, n_utilities)
edges = get_edges(all_names,
utility_names,
edge_density,
seed=seed,
allow_u_edges=False)
cid = CID(edges, decision_names, utility_names)
for uname in utility_names:
for edge in edges:
assert uname != edge[0]
for i, d1 in enumerate(decision_names):
for j, d2 in enumerate(decision_names[i + 1:]):
assert d2 not in cid._get_ancestors_of(d1)
if add_sr_edges:
add_sufficient_recalls(cid)
if add_cpds:
for node in cid.nodes:
if node in cid.all_decision_nodes:
cid.add_cpds(DecisionDomain(node, [0, 1]))
elif not cid.get_parents(node): # node is a root node
cid.add_cpds(UniformRandomCPD(node, [0, 1]))
else:
cid.add_cpds(
RandomlySampledFunctionCPD(node, cid.get_parents(node)))
return cid