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# Copyright 2022 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import re
import warnings
import torch
from accelerate.utils import extract_model_from_parallel
from transformers import StoppingCriteria, StoppingCriteriaList
from ..import_utils import is_rich_available
if is_rich_available():
from rich import print
from rich.text import Text
class StringStoppingCriteria(StoppingCriteria):
"""Custom `StoppingCriteria` which checks if all generations in the batch are completed."""
def __init__(self, stop_strings, tokenizer):
self.stop_strings = stop_strings
self.tokenizer = tokenizer
self.first_call = True
def __call__(self, input_ids, scores, **kwargs):
"""Returns true if all generated sequences contain any of the stop strings."""
if self.first_call:
self.generated_tokens = [1 for _ in range(input_ids.shape[0])]
self.start_length = input_ids.shape[-1] - 1
self.first_call = False
decoded_generations = self.tokenizer.batch_decode(input_ids[:, self.start_length :])
done = []
for i, decoded_generation in enumerate(decoded_generations):
sequence_complete = any([stop_string in decoded_generation for stop_string in self.stop_strings])
done.append(sequence_complete)
if not sequence_complete:
self.generated_tokens[i] += 1
if all(done):
self.first_call = True
return all(done)
class TextHistory:
"""The TextHistory class keeps track of the history of an interaction between the language model and the environment."""
def __init__(self, text, tokens, system=True):
"""
Initialize TextHistory.
args:
text (`str`): The text of the first segment.
tokens (`torch.LongTensor`): The tokens of the first segment.
system (`bool`, *optional*): Whether the first segment is a system or user segment.
"""
self.system_spans = []
self.text_spans = []
self.token_spans = []
self.token_masks = torch.tensor([], dtype=torch.long).to(tokens.device)
self.text = ""
self.tokens = torch.tensor([], dtype=torch.long).to(tokens.device)
self.completed = False
self.truncated = False
self.reward = 0.0
self.prompt_color = "black on grey85"
self.system_color = "black on cyan3"
self.model_color = "black on deep_sky_blue1"
self.reward_color = "black on plum1"
self.append_segment(text, tokens, system=system)
def append_segment(self, text, tokens, system=True):
"""
Append a new segment to the history.
args:
text (`str`): The text of the new segment.
tokens (`torch.LongTensor`): The tokens of the new segment.
system (`bool`, *optional*): Whether the new segment is a system or user segment.
"""
if len(text) == 0 or len(tokens) == 0:
raise ValueError("Can't append empty text or token list to history.")
original_text_length = len(self.text)
self.text += text
self.text_spans.append((original_text_length, len(self.text)))
self.system_spans.append(system)
original_token_length = len(self.tokens)
self.tokens = torch.cat((self.tokens, tokens))
if system:
self.token_masks = torch.cat((self.token_masks, torch.zeros_like(tokens)))
else:
self.token_masks = torch.cat((self.token_masks, torch.ones_like(tokens)))
self.token_spans.append((original_token_length, len(self.tokens)))
def complete(self, truncated=False):
"""
Mark the history as completed.
"""
self.completed = True
self.truncated = truncated
@property
def last_text_segment(self):
"""
Get the last text segment.
"""
start, end = self.text_spans[-1]
return self.text[start:end]
def split_query_response_tokens(self):
"""
Split the tokens into query and response tokens.
"""
split_index = self.token_spans[0][1]
query = self.tokens[:split_index]
response = self.tokens[split_index:]
mask = self.token_masks[split_index:]
return query, response, mask
def show_text(self, show_legend=False):
"""
Print the text history.
"""
if not is_rich_available():
warnings.warn("install rich to display text")
return
text = Text(self.text)
text.stylize(self.prompt_color, self.text_spans[0][0], self.text_spans[1][0])
for i, (start, end) in enumerate(self.text_spans[1:]):
if self.system_spans[i + 1]:
text.stylize(self.system_color, start, end)
else:
text.stylize(self.model_color, start, end)
text.append(f"\n\nReward: {self.reward}", style=self.reward_color)
print(text)
if show_legend:
self.show_colour_legend()
def show_tokens(self, tokenizer, show_legend=False):
"""
Print the history tokens.
"""
if not is_rich_available():
warnings.warn("install rich to display tokens")
return
text = Text()
prompt_end = self.token_spans[0][1]
for i, (token, mask) in enumerate(zip(self.tokens, self.token_masks)):
if i < prompt_end:
text.append(tokenizer.convert_ids_to_tokens(token.item()), style=self.prompt_color)
text.append(" ")
elif mask == 0:
text.append(tokenizer.convert_ids_to_tokens(token.item()), style=self.system_color)
text.append(" ")
else:
text.append(tokenizer.convert_ids_to_tokens(token.item()), style=self.model_color)
text.append(" ")
text.append(f"\n\nReward: {self.reward}", style=self.reward_color)
print(text)
if show_legend:
self.show_colour_legend()
def show_colour_legend(self):
"""
Print the colour legend.
"""
if not is_rich_available():
warnings.warn("install rich to display colour legend")
return
text = Text("\n\n(Colour Legend: ")
text.append("Prompt", style=self.prompt_color)
text.append("|")
text.append("System", style=self.system_color)
text.append("|")
text.append("Model", style=self.model_color)
text.append("|")
text.append("Reward", style=self.reward_color)
text.append(")")
print(text)
class TextEnvironment:
"""
The TextEnvironment enables interaction of a LLM with an environment using tools.
"""
def __init__(
self,
model=None,
tokenizer=None,
tools=None,
reward_fn=None,
prompt=None,
max_turns=4,
max_tool_reponse=100,
max_length=None,
generation_kwargs=None,
):
"""
Initialize TextEnvironment.
Args:
model (`PreTrainedModelWrapper`): The model to use for generation.
tokenizer (`transformers.PreTrainedTokenizer`): The tokenizer to use for generation.
tools (list): A list of tools to use for interaction.
reward_fn (function): A function that takes a string and returns a reward.
prompt (str): The base prompt to use for generation. Is prepended to the tasks.
max_turns (Optional[int]): The maximum number of turns to allow.
max_tool_response (Optional[int]): The maximum number of characters to allow in a tool response.
max_length (Optional[int]): The maximum number of tokens to allow in an episode.
generation_kwargs (Optional[dict]): A dictionary of keyword arguments to pass to the model's generate method.
"""
self.model = model
self.tokenizer = tokenizer
self.prompt = prompt
if isinstance(tools, dict):
self.tools = tools
else:
self.tools = dict([(tool.__class__.__name__, tool) for tool in tools])
self.reward_fn = reward_fn
self.max_length = max_length
self.request_token = "<request>"
self.call_token = "<call>"
self.response_token = "<response>"
self.submit_token = "<submit>"
self.max_turns = max_turns
self.max_tool_response = max_tool_reponse
if generation_kwargs is None:
self.generation_kwargs = dict()
else:
self.generation_kwargs = generation_kwargs
self.is_encoder_decoder = hasattr(self.model, "is_encoder_decoder")
self.current_device = extract_model_from_parallel(self.model).pretrained_model.device
def run(self, queries, **rewards_kwargs):
"""
Run the environment on a list of queries.
Args:
queries (list[str]): A list of queries to run the model in the environment on.
"""
turns = 0
queries = [self.prompt + task for task in queries]
queries_tokens = [self.tokenizer(query, return_tensors="pt").input_ids[0].to(self.model.pretrained_model.device) for query in queries]
histories = [TextHistory(q, qt, system=True) for q, qt in zip(queries, queries_tokens)]
while any([not history.completed for history in histories]) and turns < self.max_turns:
histories = self.generate(histories)
histories = self.tasks_end_check(histories)
# TODO: make this parallel rather than for-loop
for i in range(len(histories)):
histories[i] = self.step(histories[i])
histories = self.tasks_end_check(histories, model_turn=False)
turns += 1
self.compute_reward(histories, **rewards_kwargs)
# convert a list of (q, r, m) tuples to lists of all qs, rs, and ms respectively
queries, responses, masks = map(list, zip(*[history.split_query_response_tokens() for history in histories]))
rewards = [history.reward for history in histories]
return queries, responses, masks, rewards, histories
def step(self, history):
"""
Step the environment forward one turn.
Args:
history (`TextHistory`): The history to step forward.
"""
truncated, ended = self.task_end_check(history)
if ended:
history.complete(truncated=truncated)
if history.completed:
return history
tool, query = self.parse_tool_call(history.last_text_segment)
if tool is None or query is None:
response = f"Unknown tool call: {history.last_text_segment}"
else:
if tool not in self.tools:
response = f"Unknown tool {tool}."
try:
response = self.tools[tool](query)
except Exception as error:
response = f"Tool error: {str(error)}"
if len(response) > self.max_tool_response:
response = response[: (self.max_tool_response - 3)] + "..."
history.append_segment(
response + self.response_token,
self.tokenizer(response + self.response_token, return_tensors="pt").input_ids[0].to(self.model.pretrained_model.device),
system=True,
)
return history
def parse_tool_call(self, text):
"""
Parse request string. Expected format: <request><tool_name>query<call>
"""
result = re.search(f"(?<={self.request_token}).*?(?={self.call_token})", text, re.DOTALL)
# if we can't find a <request>/<call> span we return none
if result is None:
return None, None
else:
extracted_text = result.group()
result = re.search(r"<(.*?)>", extracted_text)
# if we can't find a tool name we return none
if result is None:
return None, None
else:
tool = result.group(1)
# split off the tool name
query = ">".join(extracted_text.split(">")[1:])
return tool, query
def compute_reward(self, histories, **reward_kwargs):
"""
Compute the reward for a list of histories.
"""
rewards = self.reward_fn([history.last_text_segment for history in histories], **reward_kwargs)
for history, reward in zip(histories, rewards):
history.reward = reward
return histories
def generate(self, histories):
"""
Generate responses for a list of histories.
"""
active_histories = [i for i, history in enumerate(histories) if not history.completed]
query_tensors = [histories[i].tokens for i in active_histories]
response_tensors = self._generate_batched(query_tensors)
response_texts = self.tokenizer.batch_decode(response_tensors)
for i, response_text, response_tensor in zip(active_histories, response_texts, response_tensors):
histories[i].append_segment(response_text, response_tensor, system=False)
return histories
def tasks_end_check(self, histories, model_turn=True):
"""
Check if the current generation sequences have finished.
"""
for history in histories:
if not history.completed:
truncated, ended = self.task_end_check(history, model_turn=model_turn)
if ended:
history.complete(truncated=truncated)
return histories
def task_end_check(self, history, model_turn=True):
"""
Check if the current generation sequence has finished.
"""
truncated = False
ended = False
if history.completed:
return truncated, ended
if self.max_length is not None and len(self.tokenizer(history.text).input_ids[0]) > self.max_length:
truncated = True
ended = True
elif self.tokenizer.eos_token in history.text:
ended = True
elif model_turn and not ((self.request_token in history.last_text_segment and self.call_token in history.last_text_segment) or self.submit_token in history.last_text_segment):
ended = True
elif self.submit_token in history.last_text_segment:
ended = True
return truncated, ended
def _generate_batched(
self,
query_tensors,
batch_size: int = 16,
pad_to_multiple_of: int = None,
):
"""
Generate responses for a list of query tensors.
args:
query_tensors (list[torch.Tensor]): A list of query tensors to generate responses for.
batch_size (int): The batch size to use for generation.
pad_to_multiple_of (int): The padding length to use for generation.
"""
outputs = []
padding_side_default = self.tokenizer.padding_side
if not self.is_encoder_decoder:
self.tokenizer.padding_side = "left"
# in case we have fewer examples than bs
batch_size = min(len(query_tensors), batch_size)
for i in range(0, len(query_tensors), batch_size):
# prevent overflow if query tensors are not even multiple of bs
end_index = min(len(query_tensors), i + batch_size)
batch = query_tensors[i:end_index]
batch_mask = [torch.ones_like(element) for element in batch]
inputs = {"input_ids": batch, "attention_mask": batch_mask}
padded_inputs = self.tokenizer.pad(
inputs,
padding=True,
max_length=None,
pad_to_multiple_of=pad_to_multiple_of,
return_tensors="pt",
).to(self.current_device)
stopping_criteria = StringStoppingCriteria([self.call_token, self.submit_token], self.tokenizer)
self.generation_kwargs["stopping_criteria"] = StoppingCriteriaList([stopping_criteria])
generations = extract_model_from_parallel(self.model).generate(**padded_inputs, **self.generation_kwargs)
for generation, mask, generated_tokens in zip(generations, padded_inputs["attention_mask"], stopping_criteria.generated_tokens):
if not self.is_encoder_decoder:
output = generation[(1 - mask).sum() :] # remove padding
else:
output = generation
if not self.is_encoder_decoder:
output = output[(mask).sum() :] # remove prompt
# remove chunk generated after stopping criteria in batch mode
outputs.append(output[:generated_tokens])
self.tokenizer.padding_side = padding_side_default
return outputs
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