1. A computer including a processor programmed to execute instructions on a computer readable storage medium with the instructions being accessible to the processor, the instructions embodying method acts for querying for data using a query, the method acts embodied by the instructions on the computer readable storage medium including: for at least some data vectors in a data space, generating respective approximations in polar coordinates; and based on the approximations, returning “k” nearest neighbors to the query, the “k” nearest neighbors being returned as an array of approximations a representing nearest neighbor vectors p.