piskvorky/gensim — Issue #69: make normalization a transformation
Author: piskvorky
Created: 2011-11-29 15:49:00+00:00
State: open

Right now the similarity computations assume *cosine similarity* and transform all vectors to unit length implicitly, inside the `*Similarity` classes.

Instead, make normalization an explicit transformation and leave it up to the user to choose which (or whether) normalization to use. Example `vector = norm_l2[lsi_model[norm_l2[tfidf_model[bow_vector]]]]`.

The most common cases (L2 norm, L1 norm, identity) should be pre-defined, probably in `gensim.matutils`.

Also connected is issue #64 (allow custom similarity metrics).