Invertible Flow Encoding with Multiply-Divide Compression Layers

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Solution Overview

Problem

Conventional flow-based models for lossless data compression suffer from poor model representation capability and low compression efficiency due to limitations in operations, primarily relying on integer addition and subtraction, which restricts probability distribution estimation.

Innovation Solution

Employ an invertible flow-based model that incorporates multiplication and division operations, constrained by model parameters, to enhance the representation capability and improve compression efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If integer addition and subtraction operations are used in flow-based models, then invertibility is ensured, but model representation capability deteriorates

Engineering Contradiction:
ImproveinvertibilityVSAvoidmodel representation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a parameter α (alpha) that controls the mixing ratio between original features and transformed features in the MRFM layer. By adjusting this parameter, the model can balance between maintaining invertibility and improving representation capability. The forward transform uses y = α ⊗ x + (1-α) ⊗ σ(Wx+b), where α allows flexible control over the transformation strength while preserving the ability to reconstruct original data.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces auxiliary variables (s1, s2, s3, s4) as intermediaries that store intermediate computation results during the forward transform. These auxiliary variables enable the division operation to be inverted by storing the necessary information for reconstruction, thus maintaining invertibility while enabling more powerful multiplication and division operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiplication and division operations are introduced, then model probability distribution estimation improves, but device complexity increases

Engineering Contradiction:
Improveprobability distribution estimationVSAvoidoperation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the complex transform operation into multiple simpler stages: linear transformation (Wx+b), activation function (σ), and mixing operation (α ⊗ x + (1-α) ⊗ σ(Wx+b)). Each stage can be independently computed and stored, reducing the complexity of any single operation while achieving the overall effect of improved probability distribution estimation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary variables s1, s2, s3, s4 act as intermediaries that break down the complex multiplication and division operations into manageable steps. By storing intermediate results, the system can perform accurate probability distribution estimation without requiring all operations to be computed simultaneously, thus reducing peak computational complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If conventional flow-based models are used, then device complexity is reduced, but compression efficiency deteriorates

Engineering Contradiction:
Improvemodel structure simplicityVSAvoidcompression efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent merges the advantages of traditional normalizing flows (invertibility) with the representational power of neural network transformations. The MRFM layer combines linear transformations, non-linear activations, and parameter-controlled mixing in a single unified operation, achieving both structural elegance and high compression efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The model uses a composite transformation approach, combining different types of operations (linear, non-linear, element-wise multiplication) within the MRFM layer. This composite structure leverages the strengths of each operation type to achieve superior compression efficiency while maintaining a relatively compact model architecture.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS12483273B2Data encoding method, data decoding method, and data processing apparatus
Publication Date: 2025.11.25 HUAWEI TECH CO LTD
  • US12483273B2 patent drawing
  • US12483273B2 patent drawing
  • US12483273B2 patent drawing

AI summary

This application relates to the field of artificial intelligence, and discloses a data encoding method, a data decoding method, and data processing apparatuses. Both the data encoding method and the data decoding method relate to an invertible flow-based model. The invertible flow-based model includes a target invertible flow layer, a model parameter of the target invertible flow layer is used to constrain an auxiliary variable generated in an inverse transform processing process, an operation corresponding to the target invertible flow layer includes a multiplication operation and a division operation that are determined based on the model parameter, and the auxiliary variable is an increment of a product of the multiplication operation or a remainder generated through the division operation.