Overview
Syllabus
Intro
The Generation Problem
Ancestral Sampling
Why do we Search?
Search Errors, Model Errors example from Neubig (2015) • Search error: the search algorithm fails to find an output that optimizes its search criterion . Model error: the output that optimizes the search criterion does not optimize accuracy
What beam size should I use?
Better Search can Hurt Results! (Koehn and Knowles 2017)
How to Fix Model Errors?
Minimum Bayes Risk Reranking
Improving Diversity in top N Choices
A Typical Model Error: Length Bias
Length Normalization
Predict the output length (Eriguchi et al. 2016)
Cautions about Sampling- based Search · Is sampling necessary for diversity?: questionable, we could do diverse beam search instead
Taught by
Graham Neubig