Distance Function

Euclidian distance

Cosine similarity

= a measure of similarity of the directions of two vectors.

• If the angle between two vectors is
  • 0 -> two vectors point to the same direction
  • 1 -> two vectors are orthogonal
  • -1 -> two vectors pointing in opposite directions

Other functions

• Chebychev distance
• Mahalanobis distance
• Hamming distance