def test_claim_4():
"""
test we can apply rule 2 forwards to rewrite pr(y|x,do(z)) as pr(y|x,z)
"""
graph = make_toy_graph()
bindings = {
'z' : set(['z']),
'x' : set(['x']),
'y' : set(['y']),
}
bind = bindings.get
root_expr = E.prob([E.v('y')], [E.v('x'), E.do(E.v('z'))])
rule = get_rule('ignore_intervention_act_forward')
sites = list(rule['site_gen'](root_expr))
assert len(sites) == 1
site, = sites
prepped_args = prepare_rule_arguments(rule['unpack_target'], site)
bound_args = bind_arguments(bind, prepped_args)
assert rule['assumption_test'](g = graph, **bound_args)
root_expr_prime = rule['apply'](site)
assert root_expr_prime == E.prob([E.v('y')], [E.v('x'), E.v('z')])
def gen_causal_rule_moves(rules, proof_state, graph):
def bind(name):
return proof_state.bindings[name]
for rule in rules:
for site in rule['site_gen'](proof_state.root_expr):
prepped_args = prepare_rule_arguments(rule['unpack_target'], site)
bound_args = bind_arguments(bind, prepped_args)
if not rule['assumption_test'](g = graph, **bound_args):
continue
succ_length = proof_state.length + 1
succ_heuristic = 0
succ_bindings = dict(proof_state.bindings)
succ_root_expr = rule['apply'](site)
original_expr = site[-1]
succ_comment = 'applied rule %s to %s' % (
rule['name'],
pleasantly_fmt(proof_state.bindings, original_expr))
succ_proof_state = ProofState(succ_length, succ_heuristic, succ_bindings, succ_root_expr,
parent=proof_state, comment=succ_comment)
yield succ_proof_state