def decode():
with tf.Session() as sess:
# Create model and load parameters.
model = create_model(sess, True)
model.batch_size = 1 # We decode one sentence at a time.
# Load vocabularies.
en_vocab_path = os.path.join(FLAGS.data_dir,
"vocab%d.en" % FLAGS.en_vocab_size)
fr_vocab_path = os.path.join(FLAGS.data_dir,
"vocab%d.fr" % FLAGS.fr_vocab_size)
en_vocab, _ = data_utils.initialize_vocabulary(en_vocab_path)
_, rev_fr_vocab = data_utils.initialize_vocabulary(fr_vocab_path)
# Decode from standard input.
sys.stdout.write("> ")
sys.stdout.flush()
sentence = sys.stdin.readline()
while sentence:
# Get token-ids for the input sentence.
token_ids = data_utils.sentence_to_token_ids(sentence, en_vocab)
# Which bucket does it belong to?
bucket_id = min([
b for b in xrange(len(_buckets))
if _buckets[b][0] > len(token_ids)
])
# Get a 1-element batch to feed the sentence to the model.
encoder_inputs, decoder_inputs, target_weights = model.get_batch(
{bucket_id: [(token_ids, [])]}, bucket_id)
# Get output logits for the sentence.
_, _, output_logits = model.step(sess, encoder_inputs,
decoder_inputs, target_weights,
bucket_id, True)
# This is a greedy decoder - outputs are just argmaxes of output_logits.
outputs = [
int(np.argmax(logit, axis=1)) for logit in output_logits
]
# If there is an EOS symbol in outputs, cut them at that point.
if data_utils.EOS_ID in outputs:
outputs = outputs[:outputs.index(data_utils.EOS_ID)]
# Print out French sentence corresponding to outputs.
print(" ".join([rev_fr_vocab[output] for output in outputs]))
print("> ", end="")
sys.stdout.flush()
sentence = sys.stdin.readline()
def train():
"""Train a en->fr translation model using WMT data."""
from utils import performancemetrics as pm
import datetime
now = datetime.datetime.now().isoformat()
log_file_path = "{0}.dat".format(now)
print("Creating log file as {0}..".format(log_file_path))
with open(log_file_path, "w") as log_file:
print("step,bleu", file=log_file)
# Prepare WMT data.
print("Preparing WMT data in %s" % FLAGS.data_dir)
en_train, fr_train, en_dev, fr_dev, _, fr_vocab_path = data_utils.prepare_wmt_data(
FLAGS.data_dir, FLAGS.en_vocab_size, FLAGS.fr_vocab_size)
_, rev_fr_vocab = data_utils.initialize_vocabulary(fr_vocab_path)
with tf.Session() as sess:
# Create model.
print("Creating %d layers of %d units." %
(FLAGS.num_layers, FLAGS.size))
model = create_model(sess, False)
# Read data into buckets and compute their sizes.
print("Reading development and training data (limit: %d)." %
FLAGS.max_train_data_size)
# TODO
dev_set = read_data(en_dev, fr_dev)
train_set = read_data(en_train, fr_train, FLAGS.max_train_data_size)
train_bucket_sizes = [len(train_set[b]) for b in xrange(len(_buckets))]
train_total_size = float(sum(train_bucket_sizes))
# A bucket scale is a list of increasing numbers from 0 to 1 that we'll use
# to select a bucket. Length of [scale[i], scale[i+1]] is proportional to
# the size if i-th training bucket, as used later.
train_buckets_scale = [
sum(train_bucket_sizes[:i + 1]) / train_total_size
for i in xrange(len(train_bucket_sizes))
]
# This is the training loop.
step_time, loss = 0.0, 0.0
current_step = 0
previous_losses = []
while True:
# Choose a bucket according to data distribution. We pick a random number
# in [0, 1] and use the corresponding interval in train_buckets_scale.
random_number_01 = np.random.random_sample()
bucket_id = min([
i for i in xrange(len(train_buckets_scale))
if train_buckets_scale[i] > random_number_01
])
# Get a batch and make a step.
start_time = time.time()
encoder_inputs, decoder_inputs, target_weights = model.get_batch(
train_set, bucket_id)
_, step_loss, _ = model.step(sess, encoder_inputs, decoder_inputs,
target_weights, bucket_id, False)
step_time += (time.time() -
start_time) / FLAGS.steps_per_checkpoint
loss += step_loss / FLAGS.steps_per_checkpoint
current_step += 1
# Once in a while, we save checkpoint, print statistics, and run evals.
if current_step % FLAGS.steps_per_checkpoint == 0:
# Print statistics for the previous epoch.
perplexity = math.exp(loss) if loss < 300 else float('inf')
print(
"global step %d learning rate %.4f step-time %.2f perplexity "
"%.2f" %
(model.global_step.eval(), model.learning_rate.eval(),
step_time, perplexity))
# Decrease learning rate if no improvement was seen over last 3 times.
if len(previous_losses) > 2 and loss > max(
previous_losses[-3:]):
sess.run(model.learning_rate_decay_op)
previous_losses.append(loss)
# Save checkpoint and zero timer and loss.
checkpoint_path = os.path.join(FLAGS.train_dir,
"translate.ckpt")
model.saver.save(sess,
checkpoint_path,
global_step=model.global_step)
step_time, loss = 0.0, 0.0
# Run evals on development set and print their perplexity.
references, candidates = [], []
for bucket_id in xrange(len(_buckets)):
if len(dev_set[bucket_id]) == 0:
print(" eval: empty bucket %d" % (bucket_id))
continue
encoder_inputs, decoder_inputs, target_weights = model.get_batch(
dev_set, bucket_id)
_, eval_loss, output_logits = model.step(
sess, encoder_inputs, decoder_inputs, target_weights,
bucket_id, True)
predictions = []
for batch in output_logits:
output = []
for logit in batch:
output.append(int(np.argmax(logit)))
# If there is an EOS symbol in outputs, cut them at that point.
if data_utils.EOS_ID in output:
output = output[:output.index(data_utils.EOS_ID)]
# append output to list of results
predictions.append(output)
# decode into sentences
for (result, expected) in zip(predictions, decoder_inputs):
candidates.append(" ".join(
[rev_fr_vocab[word_arg] for word_arg in result]))
references.append(" ".join(
[rev_fr_vocab[word_arg] for word_arg in expected]))
eval_ppx = math.exp(
eval_loss) if eval_loss < 300 else float('inf')
print(" eval: bucket %d perplexity %.2f" %
(bucket_id, eval_ppx))
eval_corp_bleu = pm.corpus_bleu(candidates, references)
print(" combined bleu score: %.5f" % (eval_corp_bleu))
with open(log_file_path, "a") as log_file:
print("{0},{1}".format(current_step, eval_corp_bleu),
file=log_file)
sys.stdout.flush()
