def call(self, texts: tf.Tensor,
substrings: tf.RaggedTensor) -> tf.RaggedTensor:
texts = tf.strings.regex_replace(texts,
pattern=self.special_chars,
rewrite='')
texts = tf.strings.strip(
tf.strings.regex_replace(texts, pattern=r'\s{2,}', rewrite=' '))
substrings = tf.strings.regex_replace(substrings,
pattern=self.special_chars,
rewrite='')
substrings = tf.strings.strip(
tf.strings.regex_replace(substrings,
pattern=r'\s{2,}',
rewrite=' '))
pre = r'.*(\s|^)'
post = r'(\s|$).*'
ragged_texts = tf.RaggedTensor.from_row_lengths(
values=tf.repeat(texts, repeats=substrings.row_lengths()),
row_lengths=substrings.row_lengths())
return tf.ragged.map_flat_values(
self.find_match, ragged_texts,
tf.strings.join([pre, substrings, post]))
def embedding_pooling(tensor: tf.RaggedTensor, combiner: str = "sqrtn"):
tensor_sum = tf.math.reduce_sum(tensor, axis=1)
if combiner == "sum":
return tensor_sum
row_lengths = tf.expand_dims(tensor.row_lengths(axis=1), axis=1)
row_lengths = tf.math.maximum(tf.ones_like(row_lengths), row_lengths)
row_lengths = tf.cast(row_lengths, dtype=tf.float32)
if combiner == "mean":
return tensor_sum / row_lengths
if combiner == "sqrtn":
return tensor_sum / tf.math.sqrt(row_lengths)
def _run_model_filter_empty_sequences(self,
batch_item_indices: tf.RaggedTensor,
batch_customer_indices, n_results):
# Check if there are empty sequences
sequences_lenghts = batch_item_indices.row_lengths()
non_empty_seq_count = tf.math.count_nonzero(sequences_lenghts)
n_sequences = tf.shape(sequences_lenghts, tf.int64)[0]
#print(">>>", non_empty_seq_count, n_results)
if non_empty_seq_count == 0:
# All sequences are empty
label_predictions = tf.zeros([n_sequences, n_results],
dtype=tf.string)
probs_predictions = tf.zeros([n_sequences, n_results],
dtype=tf.float32)
return (label_predictions, probs_predictions)
elif non_empty_seq_count >= n_sequences:
# There are no empty sequences. Run the model with the full batch
return self._run_model_and_postprocess(batch_item_indices,
batch_customer_indices,
n_results)
else:
# There are some empty sequences
# Model will fail if a sequence is empty, and it seems it's the expected behaviour: Do not feed empty sequences
# Get non empty sequences mask
non_empty_mask = tf.math.greater(sequences_lenghts, 0)
# Get non empty sequences
non_empty_sequences: tf.RaggedTensor = tf.ragged.boolean_mask(
batch_item_indices, non_empty_mask)
non_empty_customers = tf.boolean_mask(batch_customer_indices,
non_empty_mask)
# Run model
label_predictions, probs_predictions = self._run_model_and_postprocess(
non_empty_sequences, non_empty_customers, n_results)
# Merge real predictions with empty predictions for empty sequences:
indices = tf.where(non_empty_mask)
final_shape = [n_sequences, n_results]
label_predictions = tf.scatter_nd(indices, label_predictions,
final_shape)
#print(label_predictions)
probs_predictions = tf.scatter_nd(indices, probs_predictions,
final_shape)
#print(probs_predictions)
return (label_predictions, probs_predictions)
def pad_sequence_left(sequences_batch: tf.RaggedTensor, mask: bool):
""" Pad sequences with zeros on left side """
# Truncate rows to have at most `settings.SEQUENCE_LENGTH` items
sequences_batch = sequences_batch[:,-settings.settings.sequence_length:]
if mask:
# Add one to indices, to reserve 0 index for padding
sequences_batch += 1
pad_row_lengths = settings.settings.sequence_length - sequences_batch.row_lengths()
pad_values = tf.zeros( [(settings.settings.sequence_length * sequences_batch.nrows()) - tf.size(sequences_batch, tf.int64)],
sequences_batch.dtype)
padding = tf.RaggedTensor.from_row_lengths(pad_values, pad_row_lengths)
return tf.concat([padding, sequences_batch], axis=1).to_tensor()
def multi_behavior_embedding_pooling(tensor: tf.RaggedTensor,
combiner: str = "sqrtn"):
if len(tensor.shape) == 3:
tensor = tf.expand_dims(
tensor, axis=2) # batch_size * behavior_count * 1 * embedding_size
tensor_sum = tf.math.reduce_sum(
tensor, axis=2) # batch_size * behavior_count * embedding_size
if combiner == "sum":
return tensor_sum
row_lengths = tf.expand_dims(tensor.row_lengths(axis=2), axis=2)
row_lengths = tf.math.maximum(tf.ones_like(row_lengths), row_lengths)
row_lengths = tf.cast(row_lengths, dtype=tf.float32)
if combiner == "mean":
return tensor_sum / row_lengths
if combiner == "sqrtn":
return tensor_sum / tf.math.sqrt(row_lengths)
