def ObtainWRTG(weighted_tree_pair, print_result=True):
"""
Given a transducer and a weighted source/target tree, it returns a tuple
that contains the wRTG and the weighted pair. If the transducer fails at
explaining the source/target tree with the rules it has, then it returns
a tuple (None, None). The weights of the RTG are not estimated here.
global variables used here (bad practice, but need for parallelization):
* transducer
* feat_inst
* model_class
* GetScoreOfDerivation
* CombineScoresOfDerivations
"""
intree_str, outtree_str, pair_weight = weighted_tree_pair
intree = immutable(tree_or_string(intree_str))
outtree = None if outtree_str is None else immutable(tree_or_string(outtree_str))
wrtg = transducer.Transduce(intree, outtree, convert_to_prob=False)
sys.stdout.flush()
if not wrtg.P:
output = (None, None)
result_str = 'x'
else:
wrtg.ScoreDerivation = GetScoreOfDerivation
wrtg.CombineDerivationScores = CombineScoresOfDerivations
if feat_inst:
feat_inst.SetContext({'src_tree' : intree_str})
model_class.populate_wrtg_feats(wrtg, feat_inst)
output = (wrtg, weighted_tree_pair)
result_str = 'o'
if print_result:
result_str = result_str if outtree is not None else result_str.upper()
print(result_str, end='', file=sys.stderr)
return output
def test_Preterminal(self):
input_tree = immutable(tree_or_string('(B D E)'))
output_tree = immutable(tree_or_string('U'))
productions, _ = self.transducer.Produce(input_tree, output_tree, 'q',
(), ())
rule2 = XTRule('q', tree_or_string('(B ?x0| ?x1|)'),
tree_or_string('U'), {}, 1.0)
deriv_rhs = RHS(rule2)
expected_production = Production(('q', (), ()), deriv_rhs,
rule2.weight)
self.assertIn(expected_production, productions)
def test_Nonterminal(self):
input_tree = immutable(tree_or_string('(A (B D E) (C F G))'))
output_tree = immutable(tree_or_string('(A (R (T V W) U) (S X))'))
productions, _ = self.transducer.Produce(input_tree, output_tree, 'q',
(), ())
expected_productions = []
deriv_rhs1 = RHS(self.rules[0], [('q', (0, ), (0, 1)), \
('q', (1, ), (0, 0))])
expected_productions.append(\
Production(('q', (), ()), deriv_rhs1, self.rules[0].weight))
deriv_rhs2 = RHS(self.rules[1])
expected_productions.append(\
Production(('q', (0,), (0, 1)), deriv_rhs2, self.rules[1].weight))
deriv_rhs3 = RHS(self.rules[2], [('q', (1, 0), (0, 0, 0)), \
('q', (1, 1), (0, 0, 1))])
expected_productions.append(\
Production(('q', (1,), (0, 0)), deriv_rhs3, self.rules[2].weight))
deriv_rhs4 = RHS(self.rules[3], [('q', (1, 0), (0, 0, 1)), \
('q', (1, 1), (0, 0, 0))])
expected_productions.append(\
Production(('q', (1,), (0, 0)), deriv_rhs4, self.rules[3].weight))
deriv_rhs5 = RHS(self.rules[4])
expected_productions.append(\
Production(('q', (1, 0), (0, 0, 0)), deriv_rhs5, self.rules[4].weight))
deriv_rhs8 = RHS(self.rules[7])
expected_productions.append(\
Production(('q', (1, 1), (0, 0, 1)), deriv_rhs8, self.rules[7].weight))
deriv_rhs6 = RHS(self.rules[5])
expected_productions.append(\
Production(('q', (1, 0), (0, 0, 1)), deriv_rhs6, self.rules[5].weight))
deriv_rhs7 = RHS(self.rules[6])
expected_productions.append(\
Production(('q', (1, 1), (0, 0, 0)), deriv_rhs7, self.rules[6].weight))
self.assertEqual(len(expected_productions), len(productions))
self.assertIn(expected_productions[0], productions)
self.assertIn(expected_productions[1], productions)
self.assertIn(expected_productions[2], productions)
self.assertIn(expected_productions[3], productions)
self.assertIn(expected_productions[4], productions)
self.assertIn(expected_productions[5], productions)
self.assertIn(expected_productions[6], productions)
self.assertIn(expected_productions[7], productions)
def test_NonterminalPreterminalIdentity(self):
"""
Using the Identity back-off, the state of the parent rule
is applied to the paths of the variables in the RHS.
However, the states of the paths of the variables in the RHS
should be more specific: "copy" and "hypernym".
"""
intree = tree_or_string('(NP (DT the) (NN dog))')
rule0 = XTRule('q', tree_or_string('(NP ?x0|DT ?x1|NN)'),
tree_or_string('(NPP ?x0|DTT ?x1|NNN)'), {
(0, ): 'q',
(1, ): 'q'
}, 1.0)
rule1 = XTRule('q', tree_or_string('(DT ?x0|)'),
tree_or_string('(DTT ?x0|)'), {(0, ): 'copy'}, 1.0)
rule2 = XTRule('copy', tree_or_string('the'), tree_or_string('the'),
{}, 1.0)
rule3 = XTRule('hypernym', tree_or_string('dog'),
tree_or_string('canine'), {}, 1.0)
rules = [rule0, rule1, rule2, rule3]
rule_backoffs = [Identity()]
initial_state = 'q'
transducer = xT(initial_state, rules, rule_backoffs)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(
tree_or_string('(NPP (DTT the) (NN canine))'))
self.assertIn(expected_outtree, outtrees)
def test_Nonterminal(self):
input_tree = immutable(tree_or_string('(A (B D E) (C F G))'))
output_tree = immutable(tree_or_string('(A (R (T V W) U) (S X))'))
productions, non_terminals = \
self.transducer.Produce(input_tree, output_tree, 'q', (), ())
expected_non_terminals = [('q', (), (), ''), ('q', (0, ), (0, 1), ''),
('q', (1, ), (0, 0), ''),
('q', (1, 0), (0, 0, 0), ''),
('q', (1, 1), (0, 0, 1), ''),
('q', (1, 0), (0, 0, 1), ''),
('q', (1, 1), (0, 0, 0), '')]
self.assertIn(expected_non_terminals[0], non_terminals)
self.assertIn(expected_non_terminals[1], non_terminals)
self.assertIn(expected_non_terminals[2], non_terminals)
self.assertIn(expected_non_terminals[3], non_terminals)
self.assertIn(expected_non_terminals[4], non_terminals)
self.assertIn(expected_non_terminals[5], non_terminals)
self.assertIn(expected_non_terminals[6], non_terminals)
def GenerateNBestTrees(self, max_derivations = 50, direction = 'target'):
accumulated_tree_weight = defaultdict(float)
for i, (tree, weight) in enumerate(self.GenerateTrees(direction)):
if i > max_derivations:
break
tree_immutable = immutable(tree)
current_weight = float(weight)
accumulated_tree_weight[tree_immutable] += current_weight
sorted_trees_by_weight = \
sorted([(tree, weight) for (tree, weight) in accumulated_tree_weight.items()], \
key=lambda x: x[1], reverse=True)
return sorted_trees_by_weight
def GenerateNBestTreesMax(self, max_derivations = 50, direction = 'target'):
tree_to_weight = defaultdict(float)
for i, (tree, weight) in enumerate(self.GenerateTrees(direction)):
if i > max_derivations:
break
tree_immutable = immutable(tree)
current_weight = float(weight)
if tree_immutable in tree_to_weight:
assert tree_to_weight[tree_immutable] >= current_weight
continue
tree_to_weight[tree_immutable] = current_weight
yield tree, weight
def test_PreterminalIdentity(self):
intree = tree_or_string('(NN dog)')
rule1 = XTRule('q', tree_or_string('dog'), tree_or_string('perro'), {},
1.0)
rules = [rule1]
rule_backoffs = [Identity(), LexicalSimilarity()]
initial_state = 'q'
transducer = xT(initial_state, rules, rule_backoffs)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(tree_or_string('(NN perro)'))
self.assertIn(expected_outtree, outtrees)
def test_PreterminalUnseenTerminalEqual(self):
intree = tree_or_string('(NN dog)')
rule0 = XTRule('q', tree_or_string('(NN ?x0|)'),
tree_or_string('(JJ ?x0|)'), {(0, ): 'copy'}, 1.0)
rule1 = XTRule('copy', tree_or_string('italian'),
tree_or_string('italian'), {}, 1.0)
rules = [rule0, rule1]
rule_backoffs = [LexicalSimilarity()]
initial_state = 'q'
transducer = xT(initial_state, rules, rule_backoffs)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(tree_or_string('(JJ dog)'))
self.assertIn(expected_outtree, outtrees)
def GenerateNBestTreesMax_(self, max_derivations = 50, direction = 'target'):
tree_to_weight = defaultdict(float)
for i, (tree, weight) in enumerate(self.GenerateTrees(direction)):
if i > max_derivations:
break
tree_immutable = immutable(tree)
current_weight = float(weight)
if tree_immutable in tree_to_weight:
assert tree_to_weight[tree_immutable] >= current_weight
continue
tree_to_weight[tree_immutable] = current_weight
sorted_trees_by_weight = \
sorted([(tree, weight) for (tree, weight) in tree_to_weight.items()], \
key=lambda x: x[1], reverse=True)
return sorted_trees_by_weight
def test_NonConsumingLHSAvoidsInfiniteRTG(self):
intree = tree_or_string('(NN dog)')
rule0 = XTRule('q', tree_or_string('?x0|NN'),
tree_or_string('(NN ?x0|)'), {(0, ): 'q'}, 0.9)
rule1 = XTRule('q', tree_or_string('?x0|NN'),
tree_or_string('(JJ ?x0|)'), {(0, ): 't'}, 0.9)
rule2 = XTRule('t', tree_or_string('(NN dog)'),
tree_or_string('canine'), {}, 1.0)
rules = [rule0, rule1, rule2]
initial_state = 'q'
transducer = xT(initial_state, rules)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(tree_or_string('(JJ canine)'))
self.assertIn(expected_outtree, outtrees)
def test_OnlySourceDifferentVarTypes(self):
rule0 = XTRule('q', tree_or_string('(A ?x0|AA)'),
tree_or_string('(a ?x0|aa)'), {(0, ): 't'}, 1.0)
rule1 = XTRule('t', tree_or_string('(AA AAA)'),
tree_or_string('(aa aaa)'), {}, 1.0)
rule2 = XTRule('t', tree_or_string('(AA AAA)'),
tree_or_string('(bb bbb)'), {}, 1.0)
rules = [rule0, rule1, rule2]
self.transducer = xT('q', rules)
input_tree = immutable(tree_or_string('(A (AA AAA))'))
output_tree = None
productions, _ = self.transducer.Produce(input_tree, output_tree, 'q',
(), ())
self.assertEqual(2, len(productions))
self.assertIn(rule0, [p.rhs.rule for p in productions])
self.assertIn(rule1, [p.rhs.rule for p in productions])
self.assertNotIn(rule2, [p.rhs.rule for p in productions])
def test_PreterminalIdentityUnseenTerminalSimilar(self):
"""
Using the Identity back-off, the state of the parent rule
is applied to the path of the variable in the RHS.
However, the states of the path of the variable in the RHS
should be more specific: "hypernym".
"""
intree = tree_or_string('(NN dog)')
rule1 = XTRule('hypernym', tree_or_string('italian'),
tree_or_string('european'), {}, 1.0)
rules = [rule1]
rule_backoffs = [Identity(), LexicalSimilarity()]
initial_state = 'q'
transducer = xT(initial_state, rules, rule_backoffs)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(tree_or_string('(NN canine)'))
self.assertIn(expected_outtree, outtrees)
def test_NonterminalIdentityNoBackoff(self):
intree = tree_or_string('(NP (DT the) (NN dog))')
rule0 = XTRule('q', tree_or_string('(DT ?x0|)'),
tree_or_string('(DTT ?x0|)'), {(0, ): 'copy'}, 1.0)
rule1 = XTRule('copy', tree_or_string('the'), tree_or_string('the'),
{}, 1.0)
rule2 = XTRule('q', tree_or_string('(NN ?x0|)'),
tree_or_string('(NNN ?x0|)'), {(0, ): 'hypernym'}, 1.0)
rule3 = XTRule('hypernym', tree_or_string('dog'),
tree_or_string('canine'), {}, 1.0)
rules = [rule0, rule1, rule2, rule3]
rule_backoffs = []
initial_state = 'q'
transducer = xT(initial_state, rules, rule_backoffs)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(
tree_or_string('(NP (DTT the) (NNN canine))'))
self.assertNotIn(expected_outtree, outtrees)
def test_NonterminalUnseenTerminalEqualAndSimilar(self):
intree = tree_or_string('(NP (DT the) (NN dog))')
rule0 = XTRule('q', tree_or_string('(NP (DT ?x0|) (NN ?x1|))'),
tree_or_string('(NP (DT ?x0|) (NN ?x1|))'), {
(0, 0): 'copy',
(1, 0): 'hypernym'
}, 1.0)
rule1 = XTRule('copy', tree_or_string('the'), tree_or_string('the'),
{}, 1.0)
rule2 = XTRule('hypernym', tree_or_string('italian'),
tree_or_string('european'), {}, 1.0)
rules = [rule0, rule1, rule2]
rule_backoffs = [LexicalSimilarity()]
initial_state = 'q'
transducer = xT(initial_state, rules, rule_backoffs)
wrtg = transducer.Transduce(intree, None)
outtrees = [tree for tree, _ in wrtg.GenerateNBestTrees()]
expected_outtree = immutable(
tree_or_string('(NP (DT the) (NN canine))'))
self.assertIn(expected_outtree, outtrees)
def test_PreterminalEmptyRHSfail(self):
input_tree = immutable(tree_or_string('(B D E)'))
output_tree = immutable(tree_or_string('Z'))
productions, _ = self.transducer.Produce(input_tree, output_tree, 'q',
(), ())
self.assertEqual(0, len(productions))