Cosine
Implements Soft Cosine Similarity between strings.
The strings are first transformed in vectors of occurrences of k-shingles (sequences of k characters). In this n-dimensional space, the similarity between the two strings is the Cosine of their respective vectors.
The Cosine similarity between strings \(X\) and \(Y\) is the Cosine of the angle between the two strings as vectors. It is computed as: \(\frac{\vec{v_1} \cdot \vec{v_2}}{\lVert\vec{v_1}\rVert \times \lVert\vec{v_2}\rVert}\). Where, \(\vec{v_1}\) and \(\vec{v_2}\) are the vector representation of string \(X\) and \(Y\), respectively.
The distance is computed as \(1 - similarity(\vec{v_1}, \vec{v_2})\).
Author
Thibault Debatty, solonovamax
See also
Throws
if \(k \leqslant 0\)
Functions
Compute and return the profile of s, as defined by Ukkonen (Ukkonen 1992). The profile is the number of occurrences of k-shingles, and is used to compute q-gram similarity, Jaccard index, etc. Pay attention: the memory requirement of the profile can be up to \(k \times \text{size of the string}\)