class TopDownDepLM:
def __init__(self, pc, vocab, layers, state_dim, final_hidden_dim, tied,
residual):
self.vocab = vocab
self.layers = layers
self.state_dim = state_dim
self.tied = tied
self.residual = residual
self.done_with_left = vocab.convert('</LEFT>')
self.done_with_right = vocab.convert('</RIGHT>')
vocab_size = len(self.vocab)
self.pc = pc.add_subcollection()
if not self.tied:
self.word_embs = self.pc.add_lookup_parameters(
(vocab_size, state_dim))
self.top_lstm = dy.LSTMBuilder(layers, state_dim, state_dim, self.pc)
self.vertical_lstm = dy.LSTMBuilder(layers, state_dim, state_dim,
self.pc)
self.gate_mlp = MLP(self.pc, [2 * state_dim, state_dim, state_dim])
self.open_constit_lstms = []
self.debug_stack = []
self.spine = []
self.final_mlp = MLP(self.pc,
[state_dim, final_hidden_dim, vocab_size])
self.top_initial_state = [
self.pc.add_parameters((state_dim, )) for _ in range(2 * layers)
]
self.open_initial_state = [
self.pc.add_parameters((state_dim, )) for _ in range(2 * layers)
]
def set_dropout(self, r):
self.dropout_rate = r
self.top_lstm.set_dropout(r)
self.vertical_lstm.set_dropout(r)
self.final_mlp.set_dropout(r)
def new_graph(self):
# Do LSTM builders need reset?
self.final_mlp.new_graph()
self.gate_mlp.new_graph()
def embed_word(self, word):
if self.tied:
word_embs = self.final_mlp.layers[-1].w
word_emb = dy.select_rows(word_embs, [word])
word_emb = dy.transpose(word_emb)
else:
word_emb = dy.lookup(self.word_embs, word)
return word_emb
def add_to_last(self, word):
assert len(self.open_constit_lstms) > 0
word_emb = self.embed_word(word)
new_rep = self.open_constit_lstms[-1].add_input(word_emb)
self.open_constit_lstms[-1] = new_rep
self.debug_stack[-1].append(self.vocab.to_word(word))
def pop_and_add(self, word):
assert len(self.open_constit_lstms) >= 1
word_emb = self.embed_word(word)
child_state = self.open_constit_lstms[-1].add_input(word_emb)
child_emb = child_state.output()
self.open_constit_lstms.pop()
if len(self.open_constit_lstms) > 0:
self.open_constit_lstms[-1] = self.open_constit_lstms[
-1].add_input(child_emb)
self.spine.pop()
self.debug_stack[-1].append(self.vocab.to_word(word))
debug_child = self.debug_stack.pop()
if len(self.debug_stack) > 0:
self.debug_stack[-1].append(debug_child)
def push(self, word):
word_emb = self.embed_word(word)
new_state = self.vertical_lstm.initial_state()
new_state = new_state.set_s(self.open_initial_state)
new_state = new_state.add_input(word_emb)
self.open_constit_lstms.append(new_state)
self.spine.append(word)
self.debug_stack.append([self.vocab.to_word(word)])
def add_input(self, state, word):
word_emb = self.embed_word(word)
if word == self.done_with_left:
self.add_to_last(word)
elif word == self.done_with_right:
self.pop_and_add(word)
else:
self.push(word)
#print('After:', self.debug_stack)
assert len(self.debug_stack) == len(self.open_constit_lstms)
return ParserState(self.open_constit_lstms, self.spine)
def new_sent(self):
new_state = self.vertical_lstm.initial_state()
new_state = new_state.set_s(self.open_initial_state)
self.open_constit_lstms = [new_state]
self.spine = [-1]
self.debug_stack = [[]]
return ParserState(self.open_constit_lstms, self.spine)
def debug_embed_vertical(self, vertical):
state = self.vertical_lstm.initial_state()
state = state.set_s(self.open_initial_state)
for word in vertical:
if type(word) == list:
emb = self.debug_embed_vertical(word)
else:
emb = self.embed_word(self.vocab.convert(word))
state = state.add_input(emb)
return state.output()
def debug_embed(self):
top_state = self.top_lstm.initial_state()
top_state = top_state.set_s(self.top_initial_state)
assert len(self.open_constit_lstms) == len(self.debug_stack)
for i, open_constit in enumerate(self.debug_stack):
emb = self.debug_embed_vertical(open_constit)
top_state = top_state.add_input(emb)
alt = self.open_constit_lstms[i]
#c = 'O' if np.isclose(emb.npvalue(), alt.output().npvalue()).all() else 'X'
#print(c, emb.npvalue(), alt.output().npvalue())
#assert np.isclose(emb.npvalue(), alt.output().npvalue()).all()
#print()
return top_state
warned = False
def compute_loss(self, state, word):
top_state = self.top_lstm.initial_state()
top_state = top_state.set_s(self.top_initial_state)
assert len(state.open_constits) == len(state.spine)
for open_constit, spine_word in zip(state.open_constits, state.spine):
constit_emb = open_constit.output()
if self.residual and spine_word != -1:
spine_word_emb = self.embed_word(spine_word)
if False:
constit_emb += spine_word_emb
else:
inp = dy.concatenate([constit_emb, spine_word_emb])
mask = self.gate_mlp(inp)
mask = dy.logistic(mask)
constit_emb = dy.cmult(1 - mask, constit_emb)
constit_emb = constit_emb + dy.cmult(mask, spine_word_emb)
top_state = top_state.add_input(constit_emb)
#debug_top_state = self.debug_embed()
#assert np.isclose(top_state.output().npvalue(), debug_top_state.output().npvalue()).all()
logits = self.final_mlp(top_state.output())
loss = dy.pickneglogsoftmax(logits, word)
#if not self.warned:
# sys.stderr.write('WARNING: compute_loss hacked to not include actual terminals.\n')
# self.warned = True
#if word != 0 and word != 1:
# probs = -dy.softmax(logits)
# left_prob = dy.pick(probs, 0)
# right_prob = dy.pick(probs, 1)
# loss = dy.log(1 - left_prob - right_prob)
#else:
# loss = dy.pickneglogsoftmax(logits, word)
return loss
def build_graph(self, sent):
state = self.new_sent()
losses = []
for word in sent:
loss = self.compute_loss(state, word)
losses.append(loss)
state = self.add_input(state, word)
return dy.esum(losses)
class RNNLM:
def __init__(self, pc, layers, emb_dim, hidden_dim, vocab_size, tied):
self.spec = (layers, emb_dim, hidden_dim, vocab_size)
self.pc = pc.add_subcollection()
self.rnn = dy.LSTMBuilder(layers, emb_dim, hidden_dim, self.pc)
self.initial_state_params = [
self.pc.add_parameters((hidden_dim, )) for _ in range(2 * layers)
]
self.output_mlp = MLP(self.pc, [hidden_dim, hidden_dim, vocab_size])
self.tied = tied
if not self.tied:
self.word_embs = self.pc.add_lookup_parameters(
(vocab_size, emb_dim))
self.dropout_rate = 0.0
def new_graph(self):
self.output_mlp.new_graph()
self.initial_state = [
dy.parameter(p) for p in self.initial_state_params
]
#self.exp = dy.scalarInput(-0.5)
def set_dropout(self, r):
self.dropout_rate = r
self.output_mlp.set_dropout(r)
self.rnn.set_dropout(r)
def embed_word(self, word):
if self.tied:
word_embs = self.output_mlp.layers[-1].w
word_emb = dy.select_rows(word_embs, [word])
word_emb = dy.transpose(word_emb)
else:
word_emb = dy.lookup(self.word_embs, word)
# Normalize word vectors to have length one
#word_emb_norm = dy.pow(dy.dot_product(word_emb, word_emb), self.exp)
#word_emb = word_emb * word_emb_norm
return word_emb
def build_graph(self, sent):
state = self.rnn.initial_state()
state = state.set_s(self.initial_state)
losses = []
for word in sent:
assert state != None
so = state.output()
assert so != None
output_dist = self.output_mlp(so)
loss = dy.pickneglogsoftmax(output_dist, word)
losses.append(loss)
word_emb = self.embed_word(word)
if self.dropout_rate > 0.0:
word_emb = dy.dropout(word_emb, self.dropout_rate)
state = state.add_input(word_emb)
return dy.esum(losses)
def sample(self, eos, max_len):
#dy.renew_cg()
#self.new_graph()
state = self.rnn.initial_state()
state = state.set_s(self.initial_state)
sent = []
while len(sent) < max_len:
assert state != None
so = state.output()
assert so != None
output_dist = dy.softmax(self.output_mlp(so))
output_dist = output_dist.vec_value()
word = sample(output_dist)
sent.append(word)
if word == eos:
break
word_emb = self.embed_word(word)
state = state.add_input(word_emb)
return sent
def param_collection(self):
return self.pc
@staticmethod
def from_spec(spec, pc):
rnnlm = RNNLM(pc, *spec)
return rnnlm
class BottomUpDepLM:
def __init__(self,
pc,
action_vocab,
word_vocab_size,
rel_vocab_size,
layers,
hidden_dim,
labelled=True,
tied=False):
self.labelled = labelled
self.tied = tied
self.action_vocab = action_vocab
self.pc = pc.add_subcollection()
action_vocab_size = len(action_vocab)
if not self.tied:
self.word_embs = self.pc.add_lookup_parameters(
(word_vocab_size, hidden_dim))
self.action_mlp = MLP(self.pc,
[hidden_dim, hidden_dim, action_vocab_size])
self.word_mlp = MLP(self.pc, [hidden_dim, hidden_dim, word_vocab_size])
self.combine_mlp = MLP(self.pc,
[2 * hidden_dim, hidden_dim, hidden_dim])
self.stack_lstm = dy.LSTMBuilder(layers, hidden_dim, hidden_dim,
self.pc)
self.initial_state_params = [
self.pc.add_parameters((hidden_dim, )) for _ in range(2 * layers)
]
self.stack_embs = []
if labelled:
self.rel_embs = self.pc.add_lookup_parameters(
(rel_vocab_size, hidden_dim))
self.rel_mlp = MLP(self.pc,
[hidden_dim, hidden_dim, rel_vocab_size])
def new_graph(self):
self.action_mlp.new_graph()
self.word_mlp.new_graph()
self.combine_mlp.new_graph()
if self.labelled:
self.rel_mlp.new_graph()
self.initial_state = [
dy.parameter(p) for p in self.initial_state_params
]
def new_sent(self):
self.stack_embs = []
self.stack = []
state = self.stack_lstm.initial_state()
state = state.set_s(self.initial_state)
self.stack_embs.append(state)
def set_dropout(self, r):
self.action_mlp.set_dropout(r)
self.word_mlp.set_dropout(r)
self.combine_mlp.set_dropout(r)
self.stack_lstm.set_dropout(r)
if self.labelled:
self.rel_mlp.set_dropout(r)
def combine(self, head, child, direction):
head_and_child = dy.concatenate([head, child])
return self.combine_mlp(head_and_child)
def embed_word(self, word):
if self.tied:
word_embs = self.word_mlp.layers[-1].w
word_emb = dy.select_rows(word_embs, [word])
word_emb = dy.transpose(word_emb)
else:
word_emb = dy.lookup(self.word_embs, word)
return word_emb
def embed_stack_naive(self):
state = self.stack_lstm.initial_state()
state = state.set_s(self.initial_state)
for item in self.stack:
state = state.add_input(item)
return state.output()
def embed_stack(self):
return self.stack_embs[-1].output()
def pop(self):
self.stack.pop()
self.stack_embs.pop()
def push(self, v):
self.stack.append(v)
state = self.stack_embs[-1]
state = state.add_input(v)
self.stack_embs.append(state)
def shift(self, word):
word_emb = self.embed_word(word)
self.push(word_emb)
def reduce_right(self):
assert len(self.stack) >= 2
head = self.stack[-1]
child = self.stack[-2]
self.pop()
self.pop()
combined = self.combine(head, child, 'right')
self.push(combined)
def reduce_left(self):
assert len(self.stack) >= 2
head = self.stack[-2]
child = self.stack[-1]
self.pop()
self.pop()
combined = self.combine(head, child, 'left')
self.push(combined)
warned = False
def build_graph(self, sent):
losses = []
self.new_sent()
for action, subtype in sent:
action_str = self.action_vocab.to_word(action)
# predict action
hidden_state = self.embed_stack()
action_logits = self.action_mlp(hidden_state)
action_nlp = dy.pickneglogsoftmax(action_logits, action)
loss = action_nlp
if action_str == 'shift':
if not self.warned:
sys.stderr.write(
'WARNING: Hacked to not include terminal losses')
self.warned = True
#word_logits = self.word_mlp(hidden_state)
#word_nlp = dy.pickneglogsoftmax(word_logits, subtype)
#loss += word_nlp
elif self.labelled:
rel_logits = self.rel_mlp(hidden_state)
rel_nlp = dy.pickneglogsoftmax(rel_logits, subtype)
#loss += rel_nlp
losses.append(loss)
# Do the reference action
if action_str == 'shift':
self.shift(subtype)
elif action_str == 'right':
self.reduce_right()
elif action_str == 'left':
self.reduce_left()
else:
assert 'Unknown action: %s' % action_str
return dy.esum(losses)
