Question: What metrics are used for evaluation?
Answer: Byte-Pair Encoding perplexity  (BPE PPL),
BLEU-1,
BLEU-4,
ROUGE-L,
percentage of distinct unigram (D-1),
percentage of distinct bigrams(D-2),
user matching accuracy(UMA),
Mean Reciprocal Rank(MRR)
Pairwise preference over baseline(PP)
Alternative answer: BLEU-1/4 and ROUGE-L, likelihood of generated recipes using identical input specifications but conditioned on ten different user profiles, user matching accuracy (UMA), Mean Reciprocal Rank (MRR), neural scoring model from BIBREF33 to measure recipe-level coherence