LLM Tree Search with Dynamic Node Budgets for Math Reasoning

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Solution Overview

Problem

Existing tree search algorithms for large language models (LLMs) are computationally intensive and inefficient, particularly when handling complex mathematical reasoning tasks, due to wasteful search strategies and ineffective management of expansion budgets, making them difficult to deploy in practical applications.

Innovation Solution

A guided tree search algorithm with dynamic node selection and node-level exploration budget calculation, using a value network to iteratively select the most promising nodes for expansion within a computed budget, balancing exploration and exploitation to enhance 'System 2' reasoning capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tree search algorithms (BFS, MCTS) are used to enhance LLM reasoning capabilities, then the quality of mathematical reasoning improves, but computational cost increases significantly

Engineering Contradiction:
Improvemathematical reasoning accuracyVSAvoidcomputational cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by allocating different expansion budgets to different nodes based on their individual characteristics (depth, importance score). Instead of uniform treatment, each node receives customized expansion resources, allowing high-value nodes to get more computational attention while low-value nodes consume fewer resources, thus resolving the contradiction between reasoning quality and computational cost.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the expansion budget adaptive rather than static. The budget allocation changes dynamically based on node depth, importance scores, and remaining computational resources. This dynamic adjustment allows the system to optimize the balance between exploration and exploitation at different stages of the search process, improving reasoning quality while controlling computational cost.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If constant budget size is used throughout the search process (BFS approach), then implementation simplicity is maintained, but search efficiency decreases

Engineering Contradiction:
Improveimplementation simplicityVSAvoidsearch efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces the static constant budget with a dynamic budget allocation mechanism that adapts to each node's characteristics. The budget is determined based on node depth, importance scores, and problem complexity, allowing the search process to be more efficient by concentrating resources on promising paths while maintaining reasonable implementation complexity through formula-based allocation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the budget parameter from a fixed constant to a variable that depends on multiple factors including node depth, importance score, and problem characteristics. This parameter transformation enables the system to adjust resource allocation flexibly, improving search efficiency without requiring complex adaptive algorithms.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If adaptive budget based on node importance (MCTS) is used, then search focus improves, but the number of simulations required increases

Engineering Contradiction:
Improvesearch focusVSAvoidnumber of simulations
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies local quality by providing different expansion budgets to different nodes based on their importance scores and depth. High-importance nodes receive larger budgets for focused exploration, while less important nodes receive smaller budgets. This localized resource allocation improves search focus on critical paths while reducing the total number of simulations needed compared to uniform MCTS approaches.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements partial action by allocating expansion budgets selectively rather than uniformly across all nodes. Instead of performing exhaustive simulations at every node, the system applies computational effort partially and selectively to nodes that are most likely to lead to successful reasoning paths, thereby reducing the total simulation count while maintaining search effectiveness.

Inventive Principle:
Principle #16Partial or excessive action

4Measurement precision

If extensive node expansion is performed to ensure accurate statistics, then decision accuracy improves, but computational resources are wasted on nodes that do not require much expansion

Engineering Contradiction:
Improvedecision accuracyVSAvoidcomputational waste
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent applies local quality by determining expansion budgets at the individual node level based on specific characteristics such as depth, importance score, and problem complexity. This localized approach ensures that each node receives exactly the amount of expansion needed for accurate decision-making, avoiding the computational waste associated with uniform expansion strategies that over-expand low-value nodes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transforms the expansion budget from a fixed parameter to a dynamically calculated parameter that adjusts based on node-specific factors. By changing the budget parameter to reflect actual node importance and depth requirements, the system achieves accurate statistics where needed while minimizing unnecessary expansion, thereby reducing computational waste while maintaining decision accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20260064797A1Method and apparatus for efficacious tree search for llm
Publication Date: 2026.03.05 TENCENT AMERICA LLC
  • US20260064797A1 patent drawing
  • US20260064797A1 patent drawing
  • US20260064797A1 patent drawing

AI summary

A method includes: receiving a text string corresponding to a mathematical question; generating a search tree comprising a plurality of nodes by inputting the text string into a large language model (LLM) N different times, wherein the text string is the root of the search tree, wherein each node other than the root node corresponds to a search trajectory related to the mathematical question, wherein N is an integer greater than zero; determining an expansion score to each node from the plurality of nodes; selecting a node from the plurality of nodes having a highest expansion score; determining a budget for expanding the selected node; expanding the selected node in accordance with the budget by inputting the node and the mathematical questions into the one or more mathematical tasks.