Fast and Memory-Efficient Tucker Decomposition for Answering Diverse Time Range Queries

Given a temporal dense tensor and an arbitrary time range, how can we efficiently obtain latent factors in the range? Tucker decomposition is a fundamental tool for analyzing dense tensors to discover hidden factors, and has been exploited in many data mining applications. However, existing decomposition methods do not provide the functionality to analyze a specific range of a temporal tensor. The existing methods are one-off, with the main focus on performing Tucker decomposition once for a whole input tensor. Although a few existing methods with a preprocessing phase can deal with a time range query, they are still time-consuming and suffer from low accuracy. In this paper, we propose Zoom-Tucker, a fast and memory-efficient Tucker decomposition method for finding hidden factors of temporal tensor data in an arbitrary time range. Zoom-Tucker fully exploits block structure to compress a given tensor, supporting an efficient query and capturing local information. Zoom-Tucker answers diverse time range queries quickly and memory-efficiently, by elaborately decoupling the preprocessed results included in the range and carefully determining the order of computations. We demonstrate that Zoom-Tucker is up to 171.9x faster and requires up to 230x less space than existing methods while providing comparable accuracy.