03 Apr 2012

The next lab meeting will be on Wednesday April 4, 2012 at 3:30pm, in TASC1 9408.

Marzieh Razavi will be presenting the following paper: Huang and Sagae, Dynamic Programming for Linear-Time Incremental Parsing.

Incremental parsing techniques such as shift-reduce have gained popularity thanks to their efficiency, but there remains a major problem: the search is greedy and only explores a tiny fraction of the whole space (even with beam search) as opposed to dynamic programming. We show that, surprisingly, dynamic programming is in fact possible for many shift-reduce parsers, by merging “equivalent” stacks based on feature values. Empirically, our algorithm yields up to a five-fold speedup over a state-of-the-art shift-reduce dependency parser with no loss in accuracy. Better search also leads to better learning, and our final parser outperforms all previously reported dependency parsers for English and Chinese, yet is much faster.