"""RWKV models.
Based on https://github.com/saharNooby/rwkv.cpp/blob/master/rwkv/chat_with_bot.py
https://github.com/BlinkDL/ChatRWKV/blob/main/v2/chat.py
"""
from typing import Any, Dict, List, Mapping, Optional, Set
from langchain_core.callbacks import CallbackManagerForLLMRun
from langchain_core.language_models.llms import LLM
from langchain_core.utils import pre_init
from pydantic import BaseModel, ConfigDict
from langchain_community.llms.utils import enforce_stop_tokens
[docs]
class RWKV(LLM, BaseModel):
"""RWKV language models.
To use, you should have the ``rwkv`` python package installed, the
pre-trained model file, and the model's config information.
Example:
.. code-block:: python
from langchain_community.llms import RWKV
model = RWKV(model="./models/rwkv-3b-fp16.bin", strategy="cpu fp32")
# Simplest invocation
response = model.invoke("Once upon a time, ")
"""
model: str
"""Path to the pre-trained RWKV model file."""
tokens_path: str
"""Path to the RWKV tokens file."""
strategy: str = "cpu fp32"
"""Token context window."""
rwkv_verbose: bool = True
"""Print debug information."""
temperature: float = 1.0
"""The temperature to use for sampling."""
top_p: float = 0.5
"""The top-p value to use for sampling."""
penalty_alpha_frequency: float = 0.4
"""Positive values penalize new tokens based on their existing frequency
in the text so far, decreasing the model's likelihood to repeat the same
line verbatim.."""
penalty_alpha_presence: float = 0.4
"""Positive values penalize new tokens based on whether they appear
in the text so far, increasing the model's likelihood to talk about
new topics.."""
CHUNK_LEN: int = 256
"""Batch size for prompt processing."""
max_tokens_per_generation: int = 256
"""Maximum number of tokens to generate."""
client: Any = None #: :meta private:
tokenizer: Any = None #: :meta private:
pipeline: Any = None #: :meta private:
model_tokens: Any = None #: :meta private:
model_state: Any = None #: :meta private:
model_config = ConfigDict(
extra="forbid",
)
@property
def _default_params(self) -> Dict[str, Any]:
"""Get the identifying parameters."""
return {
"verbose": self.verbose,
"top_p": self.top_p,
"temperature": self.temperature,
"penalty_alpha_frequency": self.penalty_alpha_frequency,
"penalty_alpha_presence": self.penalty_alpha_presence,
"CHUNK_LEN": self.CHUNK_LEN,
"max_tokens_per_generation": self.max_tokens_per_generation,
}
@staticmethod
def _rwkv_param_names() -> Set[str]:
"""Get the identifying parameters."""
return {
"verbose",
}
[docs]
@pre_init
def validate_environment(cls, values: Dict) -> Dict:
"""Validate that the python package exists in the environment."""
try:
import tokenizers
except ImportError:
raise ImportError(
"Could not import tokenizers python package. "
"Please install it with `pip install tokenizers`."
)
try:
from rwkv.model import RWKV as RWKVMODEL
from rwkv.utils import PIPELINE
values["tokenizer"] = tokenizers.Tokenizer.from_file(values["tokens_path"])
rwkv_keys = cls._rwkv_param_names()
model_kwargs = {k: v for k, v in values.items() if k in rwkv_keys}
model_kwargs["verbose"] = values["rwkv_verbose"]
values["client"] = RWKVMODEL(
values["model"], strategy=values["strategy"], **model_kwargs
)
values["pipeline"] = PIPELINE(values["client"], values["tokens_path"])
except ImportError:
raise ImportError(
"Could not import rwkv python package. "
"Please install it with `pip install rwkv`."
)
return values
@property
def _identifying_params(self) -> Mapping[str, Any]:
"""Get the identifying parameters."""
return {
"model": self.model,
**self._default_params,
**{k: v for k, v in self.__dict__.items() if k in RWKV._rwkv_param_names()},
}
@property
def _llm_type(self) -> str:
"""Return the type of llm."""
return "rwkv"
[docs]
def run_rnn(self, _tokens: List[str], newline_adj: int = 0) -> Any:
AVOID_REPEAT_TOKENS = []
AVOID_REPEAT = "，：？！"
for i in AVOID_REPEAT:
dd = self.pipeline.encode(i)
assert len(dd) == 1
AVOID_REPEAT_TOKENS += dd
tokens = [int(x) for x in _tokens]
self.model_tokens += tokens
out: Any = None
while len(tokens) > 0:
out, self.model_state = self.client.forward(
tokens[: self.CHUNK_LEN], self.model_state
)
tokens = tokens[self.CHUNK_LEN :]
END_OF_LINE = 187
out[END_OF_LINE] += newline_adj # adjust \n probability
if self.model_tokens[-1] in AVOID_REPEAT_TOKENS:
out[self.model_tokens[-1]] = -999999999
return out
[docs]
def rwkv_generate(self, prompt: str) -> str:
self.model_state = None
self.model_tokens = []
logits = self.run_rnn(self.tokenizer.encode(prompt).ids)
begin = len(self.model_tokens)
out_last = begin
occurrence: Dict = {}
decoded = ""
for i in range(self.max_tokens_per_generation):
for n in occurrence:
logits[n] -= (
self.penalty_alpha_presence
+ occurrence[n] * self.penalty_alpha_frequency
)
token = self.pipeline.sample_logits(
logits, temperature=self.temperature, top_p=self.top_p
)
END_OF_TEXT = 0
if token == END_OF_TEXT:
break
if token not in occurrence:
occurrence[token] = 1
else:
occurrence[token] += 1
logits = self.run_rnn([token])
xxx = self.tokenizer.decode(self.model_tokens[out_last:])
if "\ufffd" not in xxx: # avoid utf-8 display issues
decoded += xxx
out_last = begin + i + 1
if i >= self.max_tokens_per_generation - 100:
break
return decoded
def _call(
self,
prompt: str,
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> str:
r"""RWKV generation
Args:
prompt: The prompt to pass into the model.
stop: A list of strings to stop generation when encountered.
Returns:
The string generated by the model.
Example:
.. code-block:: python
prompt = "Once upon a time, "
response = model.invoke(prompt, n_predict=55)
"""
text = self.rwkv_generate(prompt)
if stop is not None:
text = enforce_stop_tokens(text, stop)
return text
