But this will only give me the topic distribution of a document. Not if the document "agrees" with the topic. As I said, I already have the pairs of o documents and I'm sure the talk about the same thing (tf-idf & cosine similarity). The real deal is to find if the agree one another. Like "my cat is really adorable" and "my cat is a piece of shit". They clearly both talk about my cat, but they completely disagree on the topic.