Hierarchical softmax is a more efficient way to train word embeddings compared to a regular softmax output layer. It has been shown that for language modeling the choice of tree affects the outcome significantly. In this blog post we describe an experiment to construct semantic trees and show how they can improve the quality of the learned embeddings in common word analogy and similarity tasks.
Facebook Research’s new fastText library can learn the meaning of metadata from the text it labels. By labelling documents with the users who read them, we used fastText to hack together a “hybrid recommender” system, able to recommend documents to users using both collaborative information (“people who read this also liked that”) and whether the text in the documents is thematically similar to things they read previously. Early signs are it performs quite well, so we’ll continue to experiment with it.