Acceptance Length
A core evaluation metric for speculative decoding, denoting the average number of consecutive candidate tokens generated by the draft model that the target model accepts in a single verification pass. A larger value indicates a more pronounced speedup.
Core Facts
Timeline (last 90 days)
TV distance has two problems: first, gradients vanish for tokens with insufficient coverage; second, the prefix product in the acceptance-length objective suppresses the contribution of later positions.
Acceptance length and acceptance rate do not have a simple linear relationship: it depends on the product of the probabilities that prefix tokens are accepted one by one.
All Facts (3)
Speculative Decoding uses a small, fast draft model to predict multiple tokens in advance, which are then verified in parallel all at once by the large model.
90%UnverifiedTV distance has two problems: first, gradients vanish for tokens with insufficient coverage; second, the prefix product in the acceptance-length objective suppresses the contribution of later positions.
50%UnverifiedAcceptance length and acceptance rate do not have a simple linear relationship: it depends on the product of the probabilities that prefix tokens are accepted one by one.
50%