gensim | RARE Technologies

Making sense of word2vec

Radim Řehůřek 2014-12-23 gensim, programming 50 Comments

One year ago, Tomáš Mikolov (together with his colleagues at Google) made some ripples by releasing word2vec, an unsupervised algorithm for learning the meaning behind words. In this blog post, I’ll evaluate some extensions that have appeared over the past year, including GloVe and matrix factorization via SVD.

Doc2vec tutorial

Radim Řehůřek 2014-12-15 gensim, programming 89 Comments

The latest gensim release of 0.10.3 has a new class named Doc2Vec. All credit for this class, which is an implementation of Quoc Le & Tomáš Mikolov: “Distributed Representations of Sentences and Documents”, as well as for this tutorial, goes to the illustrious Tim Emerick. Doc2vec (aka paragraph2vec, aka sentence embeddings) modifies the word2vec algorithm to unsupervised learning of continuous …

Multicore LDA in Python: from over-night to over-lunch

Radim Řehůřek 2014-09-21 gensim 5 Comments

Latent Dirichlet Allocation (LDA), one of the most used modules in gensim, has received a major performance revamp recently. Using all your machine cores at once now, chances are the new LdaMulticore class is limited by the speed you can feed it input data. Make sure your CPU fans are in working order!

Data streaming in Python: generators, iterators, iterables

Radim Řehůřek 2014-03-31 gensim, programming 18 Comments

There are tools and concepts in computing that are very powerful but potentially confusing even to advanced users. One such concept is data streaming (aka lazy evaluation), which can be realized neatly and natively in Python. Do you know when and how to use generators, iterators and iterables?

Tutorial on Mallet in Python

Radim Řehůřek 2014-03-20 gensim, programming 32 Comments

MALLET, “MAchine Learning for LanguagE Toolkit” is a brilliant software tool. Unlike gensim, “topic modelling for humans”, which uses Python, MALLET is written in Java and spells “topic modeling” with a single “l”. Dandy.

Word2vec Tutorial

Radim Řehůřek 2014-02-02 gensim, programming 158 Comments

I never got round to writing a tutorial on how to use word2vec in gensim. It’s simple enough and the API docs are straightforward, but I know some people prefer more verbose formats. Let this post be a tutorial and a reference example.

Asymmetric LDA Priors, Christmas Edition

Radim Řehůřek 2013-12-21 gensim, programming 2 Comments

The end of the year is proving crazy busy as usual, but gensim acquired a cool new feature that I just had to blog about. Ben Trahan sent a patch that allows automatic tuning of Latent Dirichlet Allocation (LDA) hyperparameters in gensim. This means that an optimal, asymmetric alpha can now be trained directly from your data.

Performance Shootout of Nearest Neighbours: Contestants

Radim Řehůřek 2013-12-08 gensim, programming 12 Comments

Continuing the benchmark of libraries for nearest-neighbour similarity search, part 2. What is the best software out there for similarity search in high dimensional vector spaces? Document Similarity @ English Wikipedia I’m not very fond of benchmarks on artificial datasets, and similarity search in particular is sensitive to actual data densities and distance profiles. Using fake “random gaussian datasets” seemed …

Performance Shootout of Nearest Neighbours: Intro

Radim Řehůřek 2013-11-30 gensim, programming 1 Comment

Violent as the title sounds, I’ll be actually benchmarking software packages that realize the nearest-neighbour search in high dimensional vector spaces. Which approach is the fastest, easiest to use, the best? No neighbours got harmed writing this post.

Five Years of Gensim

Radim Řehůřek 2013-10-28 gensim 6 Comments

Gensim, the machine learning library for unsupervised learning I started in late 2008, will be celebrating its fifth anniversary this November. Time to reminisce and mull over its successes and failures 🙂