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[MCTS] Add self-refined MCTS (#6098)

* add reasoner

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* update code

* delete llama

* update prompts

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* update readme

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  1. 21
      applications/ColossalChat/README.md
  2. 26
      applications/ColossalChat/coati/reasoner/guided_search/llm.py
  3. 250
      applications/ColossalChat/coati/reasoner/guided_search/mcts.py
  4. 10
      applications/ColossalChat/coati/reasoner/guided_search/prompt_store/base.py
  5. 20
      applications/ColossalChat/coati/reasoner/guided_search/prompt_store/qwen.py

21
applications/ColossalChat/README.md

@ -27,11 +27,11 @@
- [Alternative Option For RLHF: SimPO](#alternative-option-for-rlhf-simple-preference-optimization-simpo)
- [Alternative Option For RLHF: ORPO](#alternative-option-for-rlhf-odds-ratio-preference-optimization-orpo)
- [Alternative Option For RLHF: KTO](#alternative-option-for-rlhf-kahneman-tversky-optimization-kto)
- [O1 Journey](#o1-journey)
- [Inference with Self-refined MCTS](#inference-with-self-refined-mcts)
- [FAQ](#faq)
- [How to save/load checkpoint](#faq)
- [How to train with limited resources](#faq)
- [The Plan](#the-plan)
- [Real-time progress](#real-time-progress)
- [Invitation to open-source contribution](#invitation-to-open-source-contribution)
- [Quick Preview](#quick-preview)
- [Authors](#authors)
@ -272,7 +272,7 @@ Odds Ratio Preference Optimization (ORPO) from this [paper](https://arxiv.org/pd
## Alternative Option For RLHF: Kahneman-Tversky Optimization (KTO)
We support the method introduced in the paper [KTO:Model Alignment as Prospect Theoretic Optimization](https://arxiv.org/pdf/2402.01306) (KTO). Which is a aligment method that directly maximize "human utility" of generation results. Read this [README](./examples/README.md) for more information.
### Inference Quantization and Serving - After Training
## Inference Quantization and Serving - After Training
We provide an online inference server and a benchmark. We aim to run inference on single GPU, so quantization is essential when using large models.
@ -281,6 +281,21 @@ We support 8-bit quantization (RTN), 4-bit quantization (GPTQ), and FP16 inferen
Online inference server scripts can help you deploy your own services.
For more details, see [`inference/`](https://github.com/hpcaitech/ColossalAI/tree/main/applications/Chat/inference).
## O1 Journey
### Inference with Self-refined MCTS
We provide the implementation of MCT Self-Refine (MCTSr) algorithm, an innovative integration of Large Language Models with Monte Carlo Tree Search.
To run inference with MCTS, simply use the following script.
```python
from coati.reasoner.guided_search.mcts import MCTS
from coati.reasoner.guided_search.prompt_store.qwen import Qwen32B_prompt_CFG
problem = "How Many R in 'Strawberry'"
search_tree = MCTS(problem=problem, max_simulations=8, cfg=Qwen32B_prompt_CFG)
answer = search_tree.simulate()
print(answer)
```
## Coati7B examples
### Generation

26
applications/ColossalChat/coati/reasoner/guided_search/llm.py

@ -0,0 +1,26 @@
import openai
from openai.types.chat.chat_completion import ChatCompletion
from openai.types.chat.chat_completion_message_param import ChatCompletionMessageParam
API_KEY = "Dummy API Key"
def get_client(base_url: str | None = None) -> openai.Client:
return openai.Client(api_key=API_KEY, base_url=base_url)
def chat_completion(
messages: list[ChatCompletionMessageParam],
model: str,
base_url: str | None = None,
temperature: float = 0.8,
**kwargs,
) -> ChatCompletion:
client = get_client(base_url)
response = client.chat.completions.create(
model=model,
messages=messages,
temperature=temperature,
**kwargs,
)
return response

250
applications/ColossalChat/coati/reasoner/guided_search/mcts.py

@ -0,0 +1,250 @@
"""
Implementation of MCTS + Self-refine algorithm.
Reference:
1. "Accessing GPT-4 level Mathematical Olympiad Solutions via Monte
Carlo Tree Self-refine with LLaMa-3 8B: A Technical Report"
2. https://github.com/BrendanGraham14/mcts-llm/
3. https://github.com/trotsky1997/MathBlackBox/
4. https://github.com/openreasoner/openr/blob/main/reason/guided_search/tree.py
"""
from __future__ import annotations
import math
from collections import deque
import numpy as np
import tqdm
from coati.reasoner.guided_search.llm import chat_completion
from coati.reasoner.guided_search.prompt_store.base import PromptCFG
from pydantic import BaseModel
class MCTSNode(BaseModel):
"""
Node for MCTS.
"""
answer: str
parent: MCTSNode = None
children: list[MCTSNode] = []
num_visits: int = 0
Q: int = 0
rewards: list[int] = []
def expand_node(self, node) -> None:
self.children.append(node)
def add_reward(self, reward: int) -> None:
self.rewards.append(reward)
self.Q = (np.min(self.rewards) + np.mean(self.rewards)) / 2
class MCTS(BaseModel):
"""
Simulation of MCTS process.
"""
problem: str
max_simulations: int
cfg: PromptCFG
C: float = 1.4
max_children: int = 2
epsilon: float = 1e-5
root: MCTSNode = None
def initialization(self):
"""
Root Initiation.
"""
# Dummy answer as root.
base_answer = self.sample_base_answer()
self.root = MCTSNode(answer=base_answer)
self.self_evaluate(self.root)
def is_fully_expanded(self, node: MCTSNode):
return len(node.children) >= self.max_children or any(child.Q > node.Q for child in node.children)
def select_node(self) -> MCTSNode:
"""
Select next node to explore.
"""
candidates: list[MCTSNode] = []
to_explore = deque([self.root])
while to_explore:
current_node = to_explore.popleft()
if not self.is_fully_expanded(current_node):
candidates.append(current_node)
to_explore.extend(current_node.children)
if not candidates:
return self.root
return max(candidates, key=self.compute_uct)
def self_evaluate(self, node: MCTSNode):
"""
Sample reward of the answer.
"""
reward = self.sample_reward(node)
node.add_reward(reward)
def back_propagation(self, node: MCTSNode):
"""
Back propagate the value of the refined answer.
"""
parent = node.parent
while parent:
best_child_Q = max(child.Q for child in parent.children)
parent.Q = (parent.Q + best_child_Q) / 2
parent.num_visits += 1
parent = parent.parent
def compute_uct(self, node: MCTSNode):
"""
Compute UCT.
"""
if node.parent is None:
return -100
return node.Q + self.C * math.sqrt(math.log(node.parent.num_visits + 1) / (node.num_visits + self.epsilon))
def simulate(self):
self.initialization()
for _ in tqdm.tqdm(range(self.max_simulations)):
node = self.select_node()
child = self.self_refine(node)
node.expand_node(child)
self.self_evaluate(child)
self.back_propagation(child)
return self.get_best_answer()
def get_best_answer(self):
to_visit = deque([self.root])
best_node = self.root
while to_visit:
current_node = to_visit.popleft()
if current_node.Q > best_node.Q:
best_node = current_node
to_visit.extend(current_node.children)
return best_node.answer
def self_refine(self, node: MCTSNode):
"""
Refine node.
"""
critique_response = chat_completion(
messages=[
{
"role": "system",
"content": self.cfg.critic_system_prompt,
},
{
"role": "user",
"content": "\n\n".join(
[
f"<problem>\n{self.problem}\n</problem>",
f"<current_answer>\n{node.answer}\n</current_answer>",
]
),
},
],
model=self.cfg.model,
base_url=self.cfg.base_url,
max_tokens=self.cfg.max_tokens,
)
critique = critique_response.choices[0].message.content
assert critique is not None
refined_answer_response = chat_completion(
messages=[
{
"role": "system",
"content": self.cfg.refine_system_prompt,
},
{
"role": "user",
"content": "\n\n".join(
[
f"<problem>\n{self.problem}\n</problem>",
f"<current_answer>\n{node.answer}\n</current_answer>",
f"<critique>\n{critique}\n</critique>",
]
),
},
],
model=self.cfg.model,
base_url=self.cfg.base_url,
max_tokens=self.cfg.max_tokens,
)
refined_answer = refined_answer_response.choices[0].message.content
assert refined_answer is not None
return MCTSNode(answer=refined_answer, parent=node)
def sample_base_answer(self):
response = chat_completion(
messages=[
{
"role": "system",
"content": "The user will provide a problem. Solve the problem. The response should begin with [reasoning process]...[Verification]... and end with [Final Answer]. \nThe answer is [answer] \n#### [answer].",
},
{
"role": "user",
"content": f"<problem>\n {self.problem} \n</problem> \nLet's think step by step",
},
],
model=self.cfg.model,
base_url=self.cfg.base_url,
max_tokens=self.cfg.max_tokens,
)
assert response.choices[0].message.content is not None
return response.choices[0].message.content
def sample_reward(self, node: MCTSNode):
"""
Calculate reward.
"""
messages = [
{
"role": "system",
"content": self.cfg.evaluate_system_prompt,
},
{
"role": "user",
"content": "\n\n".join(
[
f"<problem>\n{self.problem}\n</problem>",
f"<answer>\n{node.answer}\n</answer>",
]
),
},
]
for attempt in range(3):
try:
response = chat_completion(
messages=messages,
model=self.cfg.model,
base_url=self.cfg.base_url,
max_tokens=self.cfg.max_tokens,
)
assert response.choices[0].message.content is not None
return int(response.choices[0].message.content)
except ValueError:
messages.extend(
[
{
"role": "assistant",
"content": response.choices[0].message.content,
},
{
"role": "user",
"content": "Failed to parse reward as an integer.",
},
]
)
if attempt == 2:
raise

10
applications/ColossalChat/coati/reasoner/guided_search/prompt_store/base.py

@ -0,0 +1,10 @@
from pydantic import BaseModel
class PromptCFG(BaseModel):
model: str
base_url: str
max_tokens: int = 4096
critic_system_prompt: str
refine_system_prompt: str
evaluate_system_prompt: str

20
applications/ColossalChat/coati/reasoner/guided_search/prompt_store/qwen.py

@ -0,0 +1,20 @@
"""
Prompts for Qwen Series.
"""
from coati.reasoner.guided_search.prompt_store.base import PromptCFG
Qwen32B_prompt_CFG = PromptCFG(
base_url="http://0.0.0.0:8008/v1",
model="Qwen2.5-32B-Instruct",
critic_system_prompt="Provide a detailed and constructive critique to improve the answer. "
"Highlight specific areas that need refinement or correction.",
refine_system_prompt="""# Instruction
Refine the answer based on the critique. The response should begin with [reasoning process]...[Verification]... and end with [Final Answer].
""",
evaluate_system_prompt=(
"Analyze this answer strictly and critic, provide a reward score between -100 and 100 for the answer quality, using very strict standards. "
"Do not give a full score above 95. Make sure the reward score is an integer. "
"Return *ONLY* the score."
),
)
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