Real-Valued Embeddings and Sketches for Fast Distance and Similarity Estimation

This survey article considers methods and algorithms for fast estimation of data distance/similarity measures from formed real-valued vectors of small dimension. The methods do not use learning and mainly use random projection and sampling. Initial data are mainly high-dimensional vectors with different measures of distance (Euclidean, Manhattan, statistical, etc.) and similarity (dot product, etc.). Vector representations of non-vector data are also considered. The resultant vectors can also be used in similarity search algorithms, machine learning, etc.