Language Embeddings#

Kashgari provides several embeddings for language representation. Embedding layers will convert input sequence to tensor for downstream task. Availabel embeddings list:

class name description
BareEmbedding random init tf.keras.layers.Embedding layer for text sequence embedding
WordEmbedding pre-trained Word2Vec embedding
BERTEmbedding pre-trained BERT embedding
GPT2Embedding pre-trained GPT-2 embedding
NumericFeaturesEmbedding random init tf.keras.layers.Embedding layer for numeric feature embedding
StackedEmbedding stack other embeddings for multi-input model

All embedding classes inherit from the Embedding class and implement the embed() to embed your input sequence and embed_model property which you need to build you own Model. By providing the embed() function and embed_model property, Kashgari hides the the complexity of different language embedding from users, all you need to care is which language embedding you need.

You could check out the Embedding API here: link

Quick start#

Feature Extract From Pre-trained Embedding#

Feature Extraction is one of the major way to use pre-trained language embedding. Kashgari provides simple API for this task. All you need to is init a embedding object then call embed function. Here is the example. All embedding shares same embed API.

import kashgari
from kashgari.embeddings import BERTEmbedding

# need to spesify task for the downstream task,
# if use embedding for feature extraction, just set `task=kashgari.CLASSIFICATION`
bert = BERTEmbedding('<BERT_MODEL_FOLDER>',
                     task=kashgari.CLASSIFICATION,
                     sequence_length=100)
# call for bulk embed
embed_tensor = bert.embed([['语', '言', '模', '型']])

# call for single embed
embed_tensor = bert.embed_one(['语', '言', '模', '型'])

print(embed_tensor)
# array([[-0.5001117 ,  0.9344998 , -0.55165815, ...,  0.49122602,
#         -0.2049343 ,  0.25752577],
#        [-1.05762   , -0.43353617,  0.54398274, ..., -0.61096823,
#          0.04312163,  0.03881482],
#        [ 0.14332692, -0.42566583,  0.68867105, ...,  0.42449307,
#          0.41105768,  0.08222893],
#        ...,
#        [-0.86124015,  0.08591427, -0.34404194, ...,  0.19915134,
#         -0.34176797,  0.06111742],
#        [-0.73940575, -0.02692179, -0.5826528 , ...,  0.26934686,
#         -0.29708537,  0.01855129],
#        [-0.85489404,  0.007399  , -0.26482674, ...,  0.16851354,
#         -0.36805922, -0.0052386 ]], dtype=float32)

Classification and Labeling#

See details at classification and labeling tutorial.

Customized model#

You can access the tf.keras model of embedding and add your own layers or any kind customizion. Just need to access the embed_model property of the embedding object.