Shane Weisz
Add app using dialoGPT-finetuned beam10 no-minlen
f648ebc
import torch
from transformers import LogitsProcessor
# HuggingFace's generate function does not yet support a `min_new_tokens`, so we need to add the functionality
# ourselves by adding a custom logits processor. Adapted from:
# https://huggingface.co/transformers/v4.1.1/_modules/transformers/generation_logits_process.html#MinLengthLogitsProcessor
class MinNewTokensLogitsProcessor(LogitsProcessor):
r"""
A [`LogitsProcessor`] enforcing a minimum response length by setting the `EOS` probability to 0 until
`min_new_tokens` new tokens have been generated since `input_length`.
"""
def __init__(self, min_new_tokens: int, eos_token_id: int, input_length: int):
if not isinstance(min_new_tokens, int) or min_new_tokens < 0:
raise ValueError(f"`min_new_tokens` has to be a positive integer, but is {min_new_tokens}")
if not isinstance(eos_token_id, int) or eos_token_id < 0:
raise ValueError(f"`eos_token_id` has to be a positive integer, but is {eos_token_id}")
if not isinstance(input_length, int) or input_length < 0:
raise ValueError(f"`input_length` has to be a positive integer, but is {input_length}")
self.min_new_tokens = min_new_tokens
self.eos_token_id = eos_token_id
self.input_length = input_length
def __call__(self, input_ids: torch.LongTensor, scores: torch.FloatTensor) -> torch.FloatTensor:
if not hasattr(self, "input_length"):
raise ValueError("`save_input_length` has to be called before `__call__`")
total_length = input_ids.shape[-1]
response_len = total_length - self.input_length
if response_len < self.min_new_tokens:
scores[:, self.eos_token_id] = -float("inf")
return scores