Bi-Level Optimization for Graph Neural Network Training Loss

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Solution Overview

Problem

Graph neural network (GNN) machine learning models face performance issues due to non-identically distributed graph data, leading to inferior performance and variability in testing despite similar training data, as they often get stuck in local or global minima during training, causing inconsistent results.

Innovation Solution

The implementation of bi-level optimization methods, which involve determining a solution to an inner loss problem by finding the maximum difference between the model's loss with and without perturbation, and an outer loss problem to minimize this difference, using techniques like stochastic gradient descent and hypergradient descent to optimize model parameters and training datasets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard training methods are used on graph data, then training process is simple, but model performance deteriorates due to non-identically distributed data and convergence to local minima

Engineering Contradiction:
Improvemodel performanceVSAvoidtraining complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The training process is segmented into two distinct levels: an inner loss problem that evaluates model performance on perturbed graph data, and an outer loss problem that optimizes model parameters based on the inner loss results. This segmentation allows the system to address non-identically distributed graph data by separately handling the evaluation and optimization aspects, thereby improving model reliability while maintaining manageable training complexity through structured problem decomposition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to the training process by formulating it as a bi-level optimization problem. The inner loss problem operates at one level (evaluating loss on perturbed data), while the outer loss problem operates at a higher level (optimizing parameters based on inner loss). This dimensional escalation enables the system to escape local minima in the original loss landscape by optimizing in a transformed, multi-level optimization space, thus improving generalization performance on non-identically distributed graph data.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If graph data is used without perturbation analysis, then training is faster, but model generalization ability deteriorates due to sharp minima in loss landscape

Engineering Contradiction:
Improvetraining speedVSAvoidgeneralization ability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary perturbation of graph data before evaluating the model loss. By pre-generating perturbed versions of the graph data and using these in the inner loss problem, the system prepares advance information about the model's sensitivity to data variations. This preliminary action enables the outer loss problem to optimize for robustness against perturbations, thereby improving generalization ability without requiring extensive real-time perturbation analysis during training, thus balancing training speed with reliability.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If bi-level optimization is implemented, then model generalization improves by converging to flatter minima, but computational complexity increases

Engineering Contradiction:
Improvegeneralization abilityVSAvoidcomputational resources
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The bi-level optimization framework implements feedback by using the results of the inner loss problem (which evaluates model performance on perturbed data) to guide the outer loss problem (which optimizes model parameters). The inner loss serves as feedback information that informs the parameter optimization process, enabling the system to converge to flatter minima in the loss landscape that generalize better. This feedback mechanism improves generalization ability while managing computational resources by structuring the optimization process to leverage informative feedback efficiently.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS20240256863A1Method, System, and Computer Program Product for Improving Training Loss of Graph Neural Networks Using Bi-Level Optimization
Publication Date: 2024.08.01 VISA INTERNATIONAL SERVICE ASSOCIATION
  • US20240256863A1 patent drawing
  • US20240256863A1 patent drawing
  • US20240256863A1 patent drawing

AI summary

Methods, systems, and computer program products are provided for optimizing training loss of a graph neural network machine learning model using bi-level optimization. An example method includes receiving a training dataset comprising graph data associated with a graph, training a graph neural network (GNN) machine learning model using a loss equation according to a bi-level optimization problem and based on the training dataset, where training the GNN machine learning model using the loss equation according to the bi-level optimization problem includes determining a solution to an inner loss problem and a solution to an outer loss problem, and providing a trained GNN machine learning model based on training the GNN machine learning model.