vllm/cacheflow/sampling_params.py
2023-05-12 18:07:09 -07:00

90 lines
3.5 KiB
Python

from typing import Set
class SamplingParams:
def __init__(
self,
n: int = 1,
presence_penalty: float = 0.0,
frequency_penalty: float = 0.0,
temperature: float = 1.0,
top_p: float = 1.0,
top_k: int = -1,
use_beam_search: bool = False,
stop_token_ids: Set[int] = set(),
max_tokens: int = 16,
logprobs: int = 0,
) -> None:
self.n = n
self.presence_penalty = presence_penalty
self.frequency_penalty = frequency_penalty
self.temperature = temperature
self.top_p = top_p
self.top_k = top_k
self.use_beam_search = use_beam_search
self.stop_token_ids = stop_token_ids
self.max_tokens = max_tokens
self.logprobs = logprobs
self._verify_args()
if self.use_beam_search:
self._verity_beam_search()
elif self.temperature == 0.0:
# Zero temperature means greedy sampling.
self._verify_greedy_sampling()
def _verify_args(self) -> None:
if self.n < 1:
raise ValueError(f"n must be at least 1, got {self.n}.")
if not -2.0 <= self.presence_penalty <= 2.0:
raise ValueError("presence_penalty must be in [-2, 2], got "
f"{self.presence_penalty}.")
if not -2.0 <= self.frequency_penalty <= 2.0:
raise ValueError("frequency_penalty must be in [-2, 2], got "
f"{self.frequency_penalty}.")
if self.temperature < 0.0:
raise ValueError(
f"temperature must be non-negative, got {self.temperature}.")
if not 0.0 < self.top_p <= 1.0:
raise ValueError(f"top_p must be in (0, 1], got {self.top_p}.")
if self.top_k < -1 or self.top_k == 0:
raise ValueError(f"top_k must be -1 (disable), or at least 1, "
f"got {self.top_k}.")
if self.max_tokens < 1:
raise ValueError(
f"max_tokens must be at least 1, got {self.max_tokens}.")
if self.logprobs < 0:
raise ValueError(
f"logprobs must be non-negative, got {self.logprobs}.")
def _verity_beam_search(self) -> None:
if self.n == 1:
raise ValueError("n must be greater than 1 when using beam search.")
if self.temperature > 0.0:
raise ValueError("temperature must be 0 when using beam search.")
if self.top_p < 1.0:
raise ValueError("top_p must be 1 when using beam search.")
if self.top_k != -1:
raise ValueError("top_k must be -1 when using beam search.")
def _verify_greedy_sampling(self) -> None:
if self.n > 1:
raise ValueError("n must be 1 when using greedy sampling.")
if self.top_p < 1.0:
raise ValueError("top_p must be 1 when using greedy sampling.")
if self.top_k != -1:
raise ValueError("top_k must be -1 when using greedy sampling.")
def __repr__(self) -> str:
return (f"SamplingParams(n={self.n}, "
f"presence_penalty={self.presence_penalty}, "
f"frequency_penalty={self.frequency_penalty}, "
f"temperature={self.temperature}, "
f"top_p={self.top_p}, "
f"top_k={self.top_k},"
f"use_beam_search={self.use_beam_search}, "
f"stop_token_ids={self.stop_token_ids}, "
f"max_tokens={self.max_tokens}, "
f"logprobs={self.logprobs}")