Mutual Information Estimation via Eta-Trick Neural Network

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Solution Overview

Problem

Current methods for estimating mutual information in machine learning are computationally complex and often biased due to non-linearities in optimization processes, particularly when using the Donsker-Varadhan (DV) bound, which can introduce biases in mini-batch estimations.

Innovation Solution

The introduction of an auxiliary variable η as a Lagrange multiplier to linearize the DV bound, resulting in an unbiased stochastic gradient optimization method, referred to as the η-DV bound, which ensures proper normalization of the likelihood ratio and reduces computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the Donsker-Varadhan (DV) bound is used for mutual information estimation, then the estimation can be performed using a neural network framework, but biases are introduced due to non-linearities in the optimization process

Engineering Contradiction:
Improvemutual information estimation accuracyVSAvoidestimation unbiasedness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an auxiliary variable η as an intermediary element that mediates between the neural network predictions and the loss computation. This variable acts as a bridge that linearizes the relationship, allowing the optimization process to proceed without introducing biases from non-linearities. The auxiliary variable enables the separation of the prediction function from the normalization operation, ensuring unbiased estimation while maintaining the neural network framework.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the original DV bound formulation by introducing a new parameter η that changes the mathematical structure of the loss function. This parameter transformation converts the non-linear optimization problem into a linear one, where the neural network predictions are combined linearly with the auxiliary variable. The parameter change enables stochastic gradient descent to converge to unbiased estimates by eliminating the non-linear coupling between predictions and normalization.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If traditional mutual information estimation methods are used, then computational complexity is reduced, but bias is introduced in mini-batch estimations

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidestimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the mutual information estimation process into distinct components: the neural network prediction function f(x,y), the auxiliary variable η, and the loss computation. This segmentation allows each component to be optimized independently, with the neural network handling pattern recognition and the auxiliary variable handling normalization. The segmented approach enables efficient mini-batch processing while maintaining unbiased estimation through proper mathematical decomposition.

Inventive Principle:
Principle #1Segmentation

3Loss of information

If the neural network is trained to maximize mutual information, then the model learns meaningful representations, but the non-linear optimization introduces estimation biases

Engineering Contradiction:
Improveinformation preservationVSAvoidoptimization unbiasedness
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The auxiliary variable η serves as an intermediary that decouples the information maximization objective from the biased non-linear optimization. By introducing this mediator, the neural network can freely learn meaningful representations that maximize mutual information without the optimization process introducing biases. The auxiliary variable handles the normalization mathematically, allowing the neural network to focus on capturing genuine information relationships.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11630989B2Mutual information neural estimation with Eta-trick
Publication Date: 2023.04.18 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US11630989B2 patent drawing
  • US11630989B2 patent drawing
  • US11630989B2 patent drawing

AI summary

A computing device receives a data X and Y, each having N samples. A function f(x,y) is defined to be a trainable neural network based on the data X and the data Y. A permuted version of the data Y is created. A loss mean is computed based on the trainable neural network f(x,y), the permuted version of the sample data Y, and a trainable scalar variable η. A loss with respect to the scalar variable η and the trainable neural network is minimized. Upon determining that the loss is at or below the predetermined threshold, estimating a mutual information (MI) between a test data XT and YT. If the estimated MI is above a predetermined threshold, the test data XT and YT is deemed to be dependent. Otherwise, it is deemed to be independent.