Title
Doubly Sparse: Sparse Mixture of Sparse Experts for Efficient Softmax Inference.
Abstract
Computations for the softmax function are significantly expensive when the number of output classes is large. In this paper, we present a novel softmax inference speedup method, Doubly Sparse Softmax (DS-Softmax), that leverages sparse mixture of sparse experts to efficiently retrieve top-k classes. Different from most existing methods that require and approximate a fixed softmax, our method is learning-based and can adapt softmax weights for a better approximation. In particular, our method learns a two-level hierarchy which divides entire output class space into several partially overlapping experts. Each expert is sparse and only contains a subset of output classes. To find top-k classes, a sparse mixture enables us to find the most probable expert quickly, and the sparse expert enables us to search within a small-scale softmax. We empirically conduct evaluation on several real-world tasks (including neural machine translation, language modeling and image classification) and demonstrate that significant computation reductions can be achieved without loss of performance.
Year
Venue
DocType
2019
arXiv: Learning
Journal
Volume
Citations 
PageRank 
abs/1901.10668
0
0.34
References 
Authors
0
5
Name
Order
Citations
PageRank
Shun Liao1442.48
Ting Chen213813.81
Tian Lin381.50
Dengyong Zhou434716.15
Chong Wang500.34