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Text2Vec

Easily generate document/paragraph/sentence vectors and calculate similarity.

中文Blog

Goal of this repository is to build a tool to easily generate document/paragraph/sentence vectors for similarity calculation and as input for further machine learning models.

Requirements

  • spacy2.0 (with English model downloaded and installed)
  • gensim
  • numpy

Usage of Text to Vector (text2vec)

  • Initialize: Pre-trained Doc2Vec/Word2Vec model
import text2vec
  • input: List of Documents, doc_list is a list of documents/paragraphs/sentences.
t2v = text2vec.text2vec(doc_list)
  • output: List of Vectors of dimention N

We do such transformation by the following ways.

# Use TFIDF
docs_tfidf = t2v.get_tfidf()

# Use Latent Semantic Indexing(LSI)
docs_lsi = t2v.get_lsi()

# Use Random Projections(RP)
docs_rp = t2v.get_rp()

# Use Latent Dirichlet Allocation(LDA)
docs_lda = t2v.get_lda()

# Use Hierarchical Dirichlet Process(HDP)
docs_hdp = t2v.get_hdp()

# Use Average of Word Embeddings
docs_avgw2v = t2v.avg_wv()

# Use Weighted Word Embeddings wrt. TFIDF
docs_emb = t2v.tfidf_weighted_wv()

For a more detailed introduction of using Weighted Word Embeddings wrt. TFIDF, please read here.

Usage of Similarity Calculation (simical)

For example, we want to calculate the similarity/distance between the first two sentences in the docs_emb we just computed.

Note that cosine similarity is between 0-1 (1 is most similar while 0 is least similar). For the other similarity measurements the results are actually distance (the larget the less similar). It's better to calculate distance for all possible pairs and then rank.

# Initialize
import text2vec
sc = text2vec.simical(docs_emb[0], docs_emb[1])

# Use Cosine
simi_cos = sc.Cosine()

# Use Euclidean
simi_euc = sc.Euclidean()

# Use Triangle's Area Similarity (TS)
simi_ts = sc.Triangle()

# Use Sector's Area Similairity (SS)
simi_ss = sc.Sector()

# Use TS-SS
simi_ts_ss = sc.TS_SS()

Reference

https://radimrehurek.com/gensim/tut2.html

https://github.com/sdimi/average-word2vec

https://github.com/taki0112/Vector_Similarity