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# Copyright 2017 The TensorFlow Authors All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""PTB data loader and helpers."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
import os
# Dependency imports
import numpy as np
import tensorflow as tf
EOS_INDEX = 0
def _read_words(filename):
with tf.gfile.GFile(filename, "r") as f:
return f.read().decode("utf-8").replace("\n", "<eos>").split()
def build_vocab(filename):
data = _read_words(filename)
counter = collections.Counter(data)
count_pairs = sorted(counter.items(), key=lambda x: (-x[1], x[0]))
words, _ = list(zip(*count_pairs))
word_to_id = dict(zip(words, range(len(words))))
print("<eos>:", word_to_id["<eos>"])
global EOS_INDEX
EOS_INDEX = word_to_id["<eos>"]
return word_to_id
def _file_to_word_ids(filename, word_to_id):
data = _read_words(filename)
return [word_to_id[word] for word in data if word in word_to_id]
def ptb_raw_data(data_path=None):
"""Load PTB raw data from data directory "data_path".
Reads PTB text files, converts strings to integer ids,
and performs mini-batching of the inputs.
The PTB dataset comes from Tomas Mikolov's webpage:
http://www.fit.vutbr.cz/~imikolov/rnnlm/simple-examples.tgz
Args:
data_path: string path to the directory where simple-examples.tgz has
been extracted.
Returns:
tuple (train_data, valid_data, test_data, vocabulary)
where each of the data objects can be passed to PTBIterator.
"""
train_path = os.path.join(data_path, "ptb.train.txt")
valid_path = os.path.join(data_path, "ptb.valid.txt")
test_path = os.path.join(data_path, "ptb.test.txt")
word_to_id = build_vocab(train_path)
train_data = _file_to_word_ids(train_path, word_to_id)
valid_data = _file_to_word_ids(valid_path, word_to_id)
test_data = _file_to_word_ids(test_path, word_to_id)
vocabulary = len(word_to_id)
return train_data, valid_data, test_data, vocabulary
def ptb_iterator(raw_data, batch_size, num_steps, epoch_size_override=None):
"""Iterate on the raw PTB data.
This generates batch_size pointers into the raw PTB data, and allows
minibatch iteration along these pointers.
Args:
raw_data: one of the raw data outputs from ptb_raw_data.
batch_size: int, the batch size.
num_steps: int, the number of unrolls.
Yields:
Pairs of the batched data, each a matrix of shape [batch_size, num_steps].
The second element of the tuple is the same data time-shifted to the
right by one.
Raises:
ValueError: if batch_size or num_steps are too high.
"""
raw_data = np.array(raw_data, dtype=np.int32)
data_len = len(raw_data)
batch_len = data_len // batch_size
data = np.full([batch_size, batch_len], EOS_INDEX, dtype=np.int32)
for i in range(batch_size):
data[i] = raw_data[batch_len * i:batch_len * (i + 1)]
if epoch_size_override:
epoch_size = epoch_size_override
else:
epoch_size = (batch_len - 1) // num_steps
if epoch_size == 0:
raise ValueError("epoch_size == 0, decrease batch_size or num_steps")
# print("Number of batches per epoch: %d" % epoch_size)
for i in range(epoch_size):
x = data[:, i * num_steps:(i + 1) * num_steps]
y = data[:, i * num_steps + 1:(i + 1) * num_steps + 1]
w = np.ones_like(x)
yield (x, y, w)
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