Keras Position Embedding
Position embedding layers in Keras.
Install
pip install keras-pos-embdUsage
Trainable Embedding
from tensorflow import keras
from keras_pos_embd import PositionEmbedding
model = keras.models.Sequential()
model.add(PositionEmbedding(
input_shape=(None,),
input_dim=10, # The maximum absolute value of positions.
output_dim=2, # The dimension of embeddings.
mask_zero=10000, # The index that presents padding (because `0` will be used in relative positioning).
mode=PositionEmbedding.MODE_EXPAND,
))
model.compile('adam', 'mse')
model.summary()Note that you don't need to enable mask_zero if you want to add/concatenate other layers like word embeddings with masks:
from tensorflow import keras
from keras_pos_embd import PositionEmbedding
model = keras.models.Sequential()
model.add(keras.layers.Embedding(
input_shape=(None,),
input_dim=10,
output_dim=5,
mask_zero=True,
))
model.add(PositionEmbedding(
input_dim=100,
output_dim=5,
mode=PositionEmbedding.MODE_ADD,
))
model.compile('adam', 'mse')
model.summary()Sin & Cos Embedding
The sine and cosine embedding has no trainable weights. The layer has three modes, it works just like PositionEmbedding in expand mode:
from tensorflow import keras
from keras_pos_embd import TrigPosEmbedding
model = keras.models.Sequential()
model.add(TrigPosEmbedding(
input_shape=(None,),
output_dim=30, # The dimension of embeddings.
mode=TrigPosEmbedding.MODE_EXPAND, # Use `expand` mode
))
model.compile('adam', 'mse')
model.summary()If you want to add this embedding to existed embedding, then there is no need to add a position input in add mode:
from tensorflow import keras
from keras_pos_embd import TrigPosEmbedding
model = keras.models.Sequential()
model.add(keras.layers.Embedding(
input_shape=(None,),
input_dim=10,
output_dim=5,
mask_zero=True,
))
model.add(TrigPosEmbedding(
output_dim=5,
mode=TrigPosEmbedding.MODE_ADD,
))
model.compile('adam', 'mse')
model.summary()