def _get_rule_penalty(rule, config, examples, verbose=False):
"""Returns a "penalty" for the rule based on the given set of examples."""
# TODO(petershaw): This could potentially be more effecient by pre-indexing
# the examples in a data structure such as a Trie.
# TODO(petershaw): Could also consider sub-sampling the dataset for the
# purpose of computing these correlations.
# Optionally compute over a sample of examples only.
sample_size = config.get("sample_size", 0)
num_examples_match_source = 0
num_examples_match_target = 0
num_examples_match_source_and_target = 0
for source_str, target_str in examples:
source = tuple(source_str.split())
target = tuple(target_str.split())
match_source = rule_utils.rhs_can_maybe_derive(rule.source, source)
match_target = rule_utils.rhs_can_maybe_derive(rule.target, target)
if match_source:
num_examples_match_source += 1
if match_target:
num_examples_match_target += 1
if match_source and match_target:
num_examples_match_source_and_target += 1
if sample_size and num_examples_match_source_and_target >= sample_size:
# Break early if using sample size and found sufficient sample.
break
# Ensure that at least one example is found.
if not num_examples_match_source_and_target:
print("Rule did not match any examples.")
# TODO(petershaw): Raise instead?
return 0.0
if not num_examples_match_source:
raise ValueError("num_examples_match_source: %s" %
num_examples_match_source)
if not num_examples_match_target:
raise ValueError("num_examples_match_target: %s" %
num_examples_match_target)
if verbose:
print("_get_rule_cost: %s" % rule)
print("num_examples_match_source: %s" % num_examples_match_source)
print("num_examples_match_target: %s" % num_examples_match_target)
print("num_examples_match_source_and_target: %s" %
num_examples_match_source_and_target)
cost = 0.0
p_source_given_target = (float(num_examples_match_source_and_target) /
num_examples_match_target)
cost -= (config["source_given_target_coef"] *
math.log2(p_source_given_target))
p_target_given_source = (float(num_examples_match_source_and_target) /
num_examples_match_source)
cost -= (config["target_given_source_coef"] *
math.log2(p_target_given_source))
return cost
def test_rhs_can_maybe_derive_1(self):
rule_a = qcfg_rule.rule_from_string(
"who is NT_1 ' s boss ? ### ( Yield :output ( FindManager :recipient ( NT_1 ) ) )"
)
rule_b = qcfg_rule.rule_from_string(
"who is NT_1 ? ### ( Yield :output ( NT_1 ) )")
self.assertTrue(
rule_utils.rhs_can_maybe_derive(rule_b.source, rule_a.source))
self.assertTrue(
rule_utils.rhs_can_maybe_derive(rule_b.target, rule_a.target))
def _find_relevant_rules(current_rules, candidate_rule):
# TODO(petershaw): This can potentially be made more effecient by
# pre-indexing rules in a data structure such as a Trie.
relevant_rules = []
for rule in current_rules:
if (rule_utils.rhs_can_maybe_derive(candidate_rule.source, rule.source)
and rule_utils.rhs_can_maybe_derive(candidate_rule.target,
rule.target)):
relevant_rules.append(rule)
return relevant_rules
def _find_possible_candidates(rule_to_split, other_rules, config):
"""Return possible rule candidates."""
all_candidates = set()
for other_rule in other_rules:
if other_rule == rule_to_split:
continue
if (rule_utils.rhs_can_maybe_derive(other_rule.source,
rule_to_split.source)
and rule_utils.rhs_can_maybe_derive(other_rule.target,
rule_to_split.target)):
unifiers = unification_utils.get_rule_unifiers(
rule_to_split, other_rule, config)
candidates = {(unifier, other_rule) for unifier in unifiers}
all_candidates |= candidates
return all_candidates
def test_rhs_can_maybe_derive_8(self):
rhs = tuple("foo NT_1 NT_2 bar".split())
goal_rhs = tuple("foo foo bar buz buz".split())
self.assertFalse(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_7(self):
rhs = tuple("turn right NT_1".split())
goal_rhs = tuple("turn left turn right".split())
self.assertFalse(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_4(self):
rhs = tuple("foo".split())
goal_rhs = tuple("bar foo bar".split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_false_2(self):
rhs = tuple("NT_1 named NT_2".split())
goal_rhs = tuple("NT_1 foo".split())
self.assertFalse(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_true_5(self):
rhs = tuple("I_TURN_RIGHT NT_1".split())
goal_rhs = tuple(
"I_TURN_RIGHT I_RUN I_TURN_RIGHT I_RUN I_TURN_RIGHT I_RUN I_RUN".
split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_true_4(self):
rhs = tuple("NT_1 right".split())
goal_rhs = tuple("run after run right thrice".split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_true_2(self):
rhs = tuple("foo foo NT_1".split())
goal_rhs = tuple("foo foo bar NT_1".split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_true_1(self):
rhs = tuple("NT_1 named NT_2".split())
goal_rhs = tuple("NT_1 have a major city named NT_2".split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_10(self):
rhs = tuple("NT_1 foo bar".split())
goal_rhs = tuple("NT_1 foo xyz foo bar".split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
def test_rhs_can_maybe_derive_9(self):
rhs = tuple("NT_1 ( capital )".split())
goal_rhs = tuple("answer ( loc_1 ( smallest ( capital ) ) )".split())
self.assertTrue(rule_utils.rhs_can_maybe_derive(rhs, goal_rhs))
