Resorting to TF-IDF and SVD features

The next few sets of features are based on TF-IDF and SVD. Term Frequency-Inverse Document Frequency (TF-IDF). Is one of the algorithms at the foundation of information retrieval. Here, the algorithm is explained using a formula:

You can understand the formula using this notation: C(t) is the number of times a term t appears in a document, N is the total number of terms in the document, this results in the Term Frequency (TF). ND is the total number of documents and ND_t is the number of documents containing the term t, this provides the Inverse Document Frequency (IDF). TF-IDF for a term t is a multiplication of Term Frequency and Inverse Document Frequency for the given term t:

Without any prior knowledge, other than about the documents themselves, such a score will highlight all the terms that could easily discriminate a document from...