Learnable Loss Function Hyperparameter Optimization

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Solution Overview

Problem

Existing machine learning models are often trained using loss functions that do not directly optimize for test performance, leading to a discrepancy between training and evaluation metrics, resulting in suboptimal model performance on test data.

Innovation Solution

A computer-implemented method that determines feature vectors for machine-learned models and validation errors, optimizing a cost function to learn a vector of variable hyperparameter values that adjusts the loss function on-the-fly during training, using convex-programming-based algorithms to align the training loss with validation errors, thereby improving model performance on test data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional loss functions (e.g., log loss) are used for training, then the training process is simple and straightforward, but the model performance on test data is suboptimal due to discrepancy between training loss and evaluation metrics

Engineering Contradiction:
Improvemodel performance on test dataVSAvoidloss function complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transforms the loss function from a fixed form to a learnable parameterized form. By introducing learnable parameters that weight different loss components, the system can adapt the loss function to better align with test performance metrics while maintaining computational efficiency through gradient-based optimization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The loss function evolves dynamically during training through two-level optimization: inner loop minimizes training loss while outer loop optimizes for test performance. This dynamic adaptation allows the loss function to adjust its characteristics based on validation feedback, resolving the contradiction between simplicity and effectiveness.

Inventive Principle:
Principle #15Dynamics

2Reliability

If loss functions are optimized to directly match evaluation metrics, then model performance improves, but the optimization process becomes computationally expensive and time-consuming

Engineering Contradiction:
Improvealignment between training loss and evaluation metricVSAvoidtraining time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary alignment by incorporating validation error as a direct component in the learnable loss function. This preliminary action during training prevents the need for extensive post-training adjustments and reduces the time required to achieve optimal alignment between training objectives and evaluation metrics.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback loops where validation performance continuously informs loss function parameter updates. This feedback mechanism enables the system to efficiently converge to optimal loss function configurations without requiring exhaustive search, thereby reducing training time while maintaining alignment with evaluation metrics.

Inventive Principle:
Principle #23Feedback

3Reliability

If complex loss functions with many hyperparameters are used, then model performance can be improved, but the difficulty of tuning and optimizing the loss function increases significantly

Engineering Contradiction:
Improvemodel performanceVSAvoidloss function tuning difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The loss function performs self-tuning through automated parameter learning via gradient descent. Instead of requiring manual hyperparameter tuning, the system automatically adjusts loss weights based on validation feedback, eliminating the need for expert intervention and simplifying the tuning process while maintaining high model performance.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces an intermediary optimization layer that mediates between training loss and validation performance. This intermediary mechanism automatically handles the complexity of multi-parameter optimization by formulating it as a constrained optimization problem, thereby reducing the perceived difficulty for practitioners while achieving superior performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If extensive training iterations are performed to achieve good test performance, then model accuracy improves, but computing resources are consumed inefficiently

Engineering Contradiction:
Improvetest performanceVSAvoidcomputing resource consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary optimization of the loss function using validation data before final model evaluation. This preliminary action ensures that subsequent training iterations are highly efficient and directly contribute to test performance improvement, reducing wasted computational resources on suboptimal training configurations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms that monitor validation performance and adjust training strategies accordingly. This feedback enables early stopping when optimal performance is achieved and prevents unnecessary computation, thereby improving the efficiency of computing resource utilization while maintaining high test performance.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11657118B2Systems and methods for learning effective loss functions efficiently
Publication Date: 2023.05.23 GOOGLE LLC
  • US11657118B2 patent drawing
  • US11657118B2 patent drawing
  • US11657118B2 patent drawing

AI summary

The present disclosure provides systems and methods that learn a loss function that, when (approximately) minimized over the training data, produces a model that performs well on test data according to some error metric. The error metric need not be differentiable and may be only loosely related to the loss function. In particular, the present disclosure presents a convex-programming-based algorithm that takes as input observed data from training a small number of models and produces as output a loss function. This algorithm can be used to tune loss function hyperparameters and/or to adjust the loss function on-the-fly during training.