langchain/langchain/chains/llm.py
leo-gan fd69cc7e42
Removed duplicate BaseModel dependencies (#2471)
Removed duplicate BaseModel dependencies in class inheritances.
Also, sorted imports by `isort`.
2023-04-06 12:45:16 -07:00

220 lines
7.6 KiB
Python

"""Chain that just formats a prompt and calls an LLM."""
from __future__ import annotations
from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
from pydantic import Extra
from langchain.chains.base import Chain
from langchain.input import get_colored_text
from langchain.prompts.base import BasePromptTemplate
from langchain.prompts.prompt import PromptTemplate
from langchain.schema import BaseLanguageModel, LLMResult, PromptValue
class LLMChain(Chain):
"""Chain to run queries against LLMs.
Example:
.. code-block:: python
from langchain import LLMChain, OpenAI, PromptTemplate
prompt_template = "Tell me a {adjective} joke"
prompt = PromptTemplate(
input_variables=["adjective"], template=prompt_template
)
llm = LLMChain(llm=OpenAI(), prompt=prompt)
"""
prompt: BasePromptTemplate
"""Prompt object to use."""
llm: BaseLanguageModel
output_key: str = "text" #: :meta private:
class Config:
"""Configuration for this pydantic object."""
extra = Extra.forbid
arbitrary_types_allowed = True
@property
def input_keys(self) -> List[str]:
"""Will be whatever keys the prompt expects.
:meta private:
"""
return self.prompt.input_variables
@property
def output_keys(self) -> List[str]:
"""Will always return text key.
:meta private:
"""
return [self.output_key]
def _call(self, inputs: Dict[str, Any]) -> Dict[str, str]:
return self.apply([inputs])[0]
def generate(self, input_list: List[Dict[str, Any]]) -> LLMResult:
"""Generate LLM result from inputs."""
prompts, stop = self.prep_prompts(input_list)
return self.llm.generate_prompt(prompts, stop)
async def agenerate(self, input_list: List[Dict[str, Any]]) -> LLMResult:
"""Generate LLM result from inputs."""
prompts, stop = await self.aprep_prompts(input_list)
return await self.llm.agenerate_prompt(prompts, stop)
def prep_prompts(
self, input_list: List[Dict[str, Any]]
) -> Tuple[List[PromptValue], Optional[List[str]]]:
"""Prepare prompts from inputs."""
stop = None
if "stop" in input_list[0]:
stop = input_list[0]["stop"]
prompts = []
for inputs in input_list:
selected_inputs = {k: inputs[k] for k in self.prompt.input_variables}
prompt = self.prompt.format_prompt(**selected_inputs)
_colored_text = get_colored_text(prompt.to_string(), "green")
_text = "Prompt after formatting:\n" + _colored_text
self.callback_manager.on_text(_text, end="\n", verbose=self.verbose)
if "stop" in inputs and inputs["stop"] != stop:
raise ValueError(
"If `stop` is present in any inputs, should be present in all."
)
prompts.append(prompt)
return prompts, stop
async def aprep_prompts(
self, input_list: List[Dict[str, Any]]
) -> Tuple[List[PromptValue], Optional[List[str]]]:
"""Prepare prompts from inputs."""
stop = None
if "stop" in input_list[0]:
stop = input_list[0]["stop"]
prompts = []
for inputs in input_list:
selected_inputs = {k: inputs[k] for k in self.prompt.input_variables}
prompt = self.prompt.format_prompt(**selected_inputs)
_colored_text = get_colored_text(prompt.to_string(), "green")
_text = "Prompt after formatting:\n" + _colored_text
if self.callback_manager.is_async:
await self.callback_manager.on_text(
_text, end="\n", verbose=self.verbose
)
else:
self.callback_manager.on_text(_text, end="\n", verbose=self.verbose)
if "stop" in inputs and inputs["stop"] != stop:
raise ValueError(
"If `stop` is present in any inputs, should be present in all."
)
prompts.append(prompt)
return prompts, stop
def apply(self, input_list: List[Dict[str, Any]]) -> List[Dict[str, str]]:
"""Utilize the LLM generate method for speed gains."""
response = self.generate(input_list)
return self.create_outputs(response)
async def aapply(self, input_list: List[Dict[str, Any]]) -> List[Dict[str, str]]:
"""Utilize the LLM generate method for speed gains."""
response = await self.agenerate(input_list)
return self.create_outputs(response)
def create_outputs(self, response: LLMResult) -> List[Dict[str, str]]:
"""Create outputs from response."""
return [
# Get the text of the top generated string.
{self.output_key: generation[0].text}
for generation in response.generations
]
async def _acall(self, inputs: Dict[str, Any]) -> Dict[str, str]:
return (await self.aapply([inputs]))[0]
def predict(self, **kwargs: Any) -> str:
"""Format prompt with kwargs and pass to LLM.
Args:
**kwargs: Keys to pass to prompt template.
Returns:
Completion from LLM.
Example:
.. code-block:: python
completion = llm.predict(adjective="funny")
"""
return self(kwargs)[self.output_key]
async def apredict(self, **kwargs: Any) -> str:
"""Format prompt with kwargs and pass to LLM.
Args:
**kwargs: Keys to pass to prompt template.
Returns:
Completion from LLM.
Example:
.. code-block:: python
completion = llm.predict(adjective="funny")
"""
return (await self.acall(kwargs))[self.output_key]
def predict_and_parse(self, **kwargs: Any) -> Union[str, List[str], Dict[str, str]]:
"""Call predict and then parse the results."""
result = self.predict(**kwargs)
if self.prompt.output_parser is not None:
return self.prompt.output_parser.parse(result)
else:
return result
async def apredict_and_parse(
self, **kwargs: Any
) -> Union[str, List[str], Dict[str, str]]:
"""Call apredict and then parse the results."""
result = await self.apredict(**kwargs)
if self.prompt.output_parser is not None:
return self.prompt.output_parser.parse(result)
else:
return result
def apply_and_parse(
self, input_list: List[Dict[str, Any]]
) -> Sequence[Union[str, List[str], Dict[str, str]]]:
"""Call apply and then parse the results."""
result = self.apply(input_list)
return self._parse_result(result)
def _parse_result(
self, result: List[Dict[str, str]]
) -> Sequence[Union[str, List[str], Dict[str, str]]]:
if self.prompt.output_parser is not None:
return [
self.prompt.output_parser.parse(res[self.output_key]) for res in result
]
else:
return result
async def aapply_and_parse(
self, input_list: List[Dict[str, Any]]
) -> Sequence[Union[str, List[str], Dict[str, str]]]:
"""Call apply and then parse the results."""
result = await self.aapply(input_list)
return self._parse_result(result)
@property
def _chain_type(self) -> str:
return "llm_chain"
@classmethod
def from_string(cls, llm: BaseLanguageModel, template: str) -> Chain:
"""Create LLMChain from LLM and template."""
prompt_template = PromptTemplate.from_template(template)
return cls(llm=llm, prompt=prompt_template)