Edinburgh Neural Machine Translation Systems for WMT 16
Table 2: English↔German translation results (Bleu) on dev (newstest2015) and test (newstest2016). Submitted system in bold.
['system', 'EN→DE dev', 'EN→DE test', 'DE→EN dev', 'DE→EN test']
We observe improvements of 3.4–5.7 Bleu from training with a mix of parallel and synthetic data, compared to the baseline that is only trained on parallel data. Using an ensemble of the last 4 checkpoints gives further improvements (1.3–1.7 Bleu). Our submitted system includes reranking of the 50-best output of the left-to-right model with a right-to-left model – again an ensemble of the last 4 checkpoints – with uniform weights. This yields an improvements of 0.6–1.1 Bleu.