Reinforcement Learning Agent for Molecular Structure Generation

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Solution Overview

Problem

Existing techniques for generating small molecule compound structures using reinforcement learning and SMILES generation suffer from a poor fit between sequence generation and pretraining operations, leading to exposure bias and an inability to control the generation of compounds with specific characteristics.

Innovation Solution

Implementing scheduled sampling in the pretraining operation and training agents with both a model likelihood reward and a self-defined reward based on target requirements to improve the fit and controllability of small molecule compound structure generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If reinforcement learning technique is used to generate SMILES sequences, then small molecule compounds can be generated, but the generated sequences have insufficient diversity

Engineering Contradiction:
Improvegeneration efficiencyVSAvoidsequence diversity
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback mechanism where the generated SMILES sequences are evaluated against multiple objectives including diversity metrics. The reinforcement learning agent receives feedback signals that encourage exploration of diverse chemical space while maintaining generation efficiency through optimized reward functions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs dynamic temperature scheduling and adaptive exploration strategies that adjust the generation process over time. The system dynamically balances exploitation of known good sequences with exploration of diverse chemical space, allowing both efficient generation and high diversity to be achieved at different stages of the process.

Inventive Principle:
Principle #15Dynamics

2Extent of automation

If pretraining operation is performed to train the agent, then the agent can generate sequences, but a poor fit exists between sequence generation technique and pretraining operation leading to exposure bias

Engineering Contradiction:
Improveagent generation capabilityVSAvoidfit between generation and pretraining
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent performs preliminary alignment between the pretraining objective and the sequence generation objective. The pretraining phase is designed to explicitly prepare the model for the eventual generation task by using objective functions and data sampling strategies that match the generation criteria, thereby eliminating exposure bias before the agent begins generating sequences.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent adjusts key parameters during pretraining including temperature, sampling strategies, and objective function weights to ensure they match the conditions under which sequences will be generated. This parameter alignment between pretraining and generation phases ensures the agent learns distributions that are directly applicable to the generation task.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If SMILES string generation technique is used, then small molecule sequences can be generated, but the technique cannot be controlled to generate compounds with required characteristics

Engineering Contradiction:
Improvesequence generation rateVSAvoidcontrollability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent implements controlled feedback mechanisms where desired compound characteristics are encoded into the reward function. The generation process receives feedback signals that guide the agent toward producing sequences with specific properties such as molecular weight ranges, functional group presence, or other chemically relevant features while maintaining generation speed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent segments the control objectives into multiple independent reward components, each corresponding to a specific molecular characteristic. This allows the system to control different aspects of compound generation independently through weighted combination of reward signals, providing fine-grained controllability without sacrificing generation throughput.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20220198330A1Method and system for generating molecular structure of chemical compound
Publication Date: 2022.06.23 ALIBABA GROUP HOLDING LTD
  • US20220198330A1 patent drawing
  • US20220198330A1 patent drawing
  • US20220198330A1 patent drawing

AI summary

Generation of a molecular structure of a chemical compound is disclosed. A target agent is trained based on a first reward and a second reward, the first reward being a reward determined by a model likelihood of a target neural network model, the second reward being a reward self-defined based on target requirements, and the target agent being used to determine a molecular compound structure. A target molecular structure of a chemical compound is generated using the target agent.