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1f5470c | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 | """Deprecated sequence preprocessing APIs from Keras 1."""
import json
import random
import numpy as np
from keras.src.api_export import keras_export
from keras.src.trainers.data_adapters.py_dataset_adapter import PyDataset
@keras_export("keras._legacy.preprocessing.sequence.TimeseriesGenerator")
class TimeseriesGenerator(PyDataset):
"""Utility class for generating batches of temporal data.
DEPRECATED.
This class takes in a sequence of data-points gathered at
equal intervals, along with time series parameters such as
stride, length of history, etc., to produce batches for
training/validation.
Arguments:
data: Indexable generator (such as list or Numpy array)
containing consecutive data points (timesteps).
The data should be at 2D, and axis 0 is expected
to be the time dimension.
targets: Targets corresponding to timesteps in `data`.
It should have same length as `data`.
length: Length of the output sequences (in number of timesteps).
sampling_rate: Period between successive individual timesteps
within sequences. For rate `r`, timesteps
`data[i]`, `data[i-r]`, ... `data[i - length]`
are used for create a sample sequence.
stride: Period between successive output sequences.
For stride `s`, consecutive output samples would
be centered around `data[i]`, `data[i+s]`, `data[i+2*s]`, etc.
start_index: Data points earlier than `start_index` will not be used
in the output sequences. This is useful to reserve part of the
data for test or validation.
end_index: Data points later than `end_index` will not be used
in the output sequences. This is useful to reserve part of the
data for test or validation.
shuffle: Whether to shuffle output samples,
or instead draw them in chronological order.
reverse: Boolean: if `true`, timesteps in each output sample will be
in reverse chronological order.
batch_size: Number of timeseries samples in each batch
(except maybe the last one).
Returns:
A PyDataset instance.
"""
def __init__(
self,
data,
targets,
length,
sampling_rate=1,
stride=1,
start_index=0,
end_index=None,
shuffle=False,
reverse=False,
batch_size=128,
):
if len(data) != len(targets):
raise ValueError(
"Data and targets have to be "
f"of same length. Data length is {len(data)} "
f"while target length is {len(targets)}"
)
self.data = data
self.targets = targets
self.length = length
self.sampling_rate = sampling_rate
self.stride = stride
self.start_index = start_index + length
if end_index is None:
end_index = len(data) - 1
self.end_index = end_index
self.shuffle = shuffle
self.reverse = reverse
self.batch_size = batch_size
if self.start_index > self.end_index:
raise ValueError(
f"`start_index+length={self.start_index} "
f"> end_index={self.end_index}` "
"is disallowed, as no part of the sequence "
"would be left to be used as current step."
)
def __len__(self):
return (
self.end_index - self.start_index + self.batch_size * self.stride
) // (self.batch_size * self.stride)
def __getitem__(self, index):
if self.shuffle:
rows = np.random.randint(
self.start_index, self.end_index + 1, size=self.batch_size
)
else:
i = self.start_index + self.batch_size * self.stride * index
rows = np.arange(
i,
min(i + self.batch_size * self.stride, self.end_index + 1),
self.stride,
)
samples = np.array(
[
self.data[row - self.length : row : self.sampling_rate]
for row in rows
]
)
targets = np.array([self.targets[row] for row in rows])
if self.reverse:
return samples[:, ::-1, ...], targets
return samples, targets
def get_config(self):
"""Returns the TimeseriesGenerator configuration as Python dictionary.
Returns:
A Python dictionary with the TimeseriesGenerator configuration.
"""
data = self.data
if type(self.data).__module__ == np.__name__:
data = self.data.tolist()
try:
json_data = json.dumps(data)
except TypeError as e:
raise TypeError(f"Data not JSON Serializable: {data}") from e
targets = self.targets
if type(self.targets).__module__ == np.__name__:
targets = self.targets.tolist()
try:
json_targets = json.dumps(targets)
except TypeError as e:
raise TypeError(f"Targets not JSON Serializable: {targets}") from e
return {
"data": json_data,
"targets": json_targets,
"length": self.length,
"sampling_rate": self.sampling_rate,
"stride": self.stride,
"start_index": self.start_index,
"end_index": self.end_index,
"shuffle": self.shuffle,
"reverse": self.reverse,
"batch_size": self.batch_size,
}
def to_json(self, **kwargs):
"""Returns a JSON string containing the generator's configuration.
Args:
**kwargs: Additional keyword arguments to be passed
to `json.dumps()`.
Returns:
A JSON string containing the tokenizer configuration.
"""
config = self.get_config()
timeseries_generator_config = {
"class_name": self.__class__.__name__,
"config": config,
}
return json.dumps(timeseries_generator_config, **kwargs)
@keras_export("keras._legacy.preprocessing.sequence.make_sampling_table")
def make_sampling_table(size, sampling_factor=1e-5):
"""Generates a word rank-based probabilistic sampling table.
DEPRECATED.
Used for generating the `sampling_table` argument for `skipgrams`.
`sampling_table[i]` is the probability of sampling
the word i-th most common word in a dataset
(more common words should be sampled less frequently, for balance).
The sampling probabilities are generated according
to the sampling distribution used in word2vec:
```
p(word) = (min(1, sqrt(word_frequency / sampling_factor) /
(word_frequency / sampling_factor)))
```
We assume that the word frequencies follow Zipf's law (s=1) to derive
a numerical approximation of frequency(rank):
`frequency(rank) ~ 1/(rank * (log(rank) + gamma) + 1/2 - 1/(12*rank))`
where `gamma` is the Euler-Mascheroni constant.
Args:
size: Int, number of possible words to sample.
sampling_factor: The sampling factor in the word2vec formula.
Returns:
A 1D Numpy array of length `size` where the ith entry
is the probability that a word of rank i should be sampled.
"""
gamma = 0.577
rank = np.arange(size)
rank[0] = 1
inv_fq = rank * (np.log(rank) + gamma) + 0.5 - 1.0 / (12.0 * rank)
f = sampling_factor * inv_fq
return np.minimum(1.0, f / np.sqrt(f))
@keras_export("keras._legacy.preprocessing.sequence.skipgrams")
def skipgrams(
sequence,
vocabulary_size,
window_size=4,
negative_samples=1.0,
shuffle=True,
categorical=False,
sampling_table=None,
seed=None,
):
"""Generates skipgram word pairs.
DEPRECATED.
This function transforms a sequence of word indexes (list of integers)
into tuples of words of the form:
- (word, word in the same window), with label 1 (positive samples).
- (word, random word from the vocabulary), with label 0 (negative samples).
Read more about Skipgram in this gnomic paper by Mikolov et al.:
[Efficient Estimation of Word Representations in
Vector Space](http://arxiv.org/pdf/1301.3781v3.pdf)
Args:
sequence: A word sequence (sentence), encoded as a list
of word indices (integers). If using a `sampling_table`,
word indices are expected to match the rank
of the words in a reference dataset (e.g. 10 would encode
the 10-th most frequently occurring token).
Note that index 0 is expected to be a non-word and will be skipped.
vocabulary_size: Int, maximum possible word index + 1
window_size: Int, size of sampling windows (technically half-window).
The window of a word `w_i` will be
`[i - window_size, i + window_size+1]`.
negative_samples: Float >= 0. 0 for no negative (i.e. random) samples.
1 for same number as positive samples.
shuffle: Whether to shuffle the word couples before returning them.
categorical: bool. if False, labels will be
integers (eg. `[0, 1, 1 .. ]`),
if `True`, labels will be categorical, e.g.
`[[1,0],[0,1],[0,1] .. ]`.
sampling_table: 1D array of size `vocabulary_size` where the entry i
encodes the probability to sample a word of rank i.
seed: Random seed.
Returns:
couples, labels: where `couples` are int pairs and
`labels` are either 0 or 1.
Note:
By convention, index 0 in the vocabulary is
a non-word and will be skipped.
"""
couples = []
labels = []
for i, wi in enumerate(sequence):
if not wi:
continue
if sampling_table is not None:
if sampling_table[wi] < random.random():
continue
window_start = max(0, i - window_size)
window_end = min(len(sequence), i + window_size + 1)
for j in range(window_start, window_end):
if j != i:
wj = sequence[j]
if not wj:
continue
couples.append([wi, wj])
if categorical:
labels.append([0, 1])
else:
labels.append(1)
if negative_samples > 0:
num_negative_samples = int(len(labels) * negative_samples)
words = [c[0] for c in couples]
random.shuffle(words)
couples += [
[words[i % len(words)], random.randint(1, vocabulary_size - 1)]
for i in range(num_negative_samples)
]
if categorical:
labels += [[1, 0]] * num_negative_samples
else:
labels += [0] * num_negative_samples
if shuffle:
if seed is None:
seed = random.randint(0, 10e6)
random.seed(seed)
random.shuffle(couples)
random.seed(seed)
random.shuffle(labels)
return couples, labels
|