Sparse MoE Gating With Differentiable Expert Selection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing mixture of experts (MoE) implementations in neural networks face significant training time and computational costs due to their non-differentiable gating mechanisms, limiting efficient training methods and resource utilization.

Innovation Solution

A novel, sparse and continuously differentiable gating mechanism for MoE networks using a binary encoding method, enabling efficient training with gradient-based optimization techniques and allowing explicit control over the number of expert neural networks used, thereby maintaining resource efficiency during inference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a non-differentiable gating mechanism is used in MoE networks, then computational capacity can be increased by selecting only a small number of expert neural networks, but training time and computational costs increase significantly

Engineering Contradiction:
Improvecomputational capacityVSAvoidtraining time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent transforms the gating mechanism from a non-differentiable discrete selection process to a continuously differentiable process by changing the parameter space. Instead of directly selecting discrete expert networks, the system uses continuous relaxation with softmax functions and binary encoding, allowing gradient-based optimization while maintaining sparse selection capability. This parameter transformation enables efficient training without sacrificing computational capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces intermediate variables and mechanisms to bridge the gap between discrete expert selection and continuous optimization. The binary encoding scheme and continuous relaxation act as intermediaries that allow the system to maintain sparse expert selection while enabling gradient flow through the gating mechanism. This intermediary layer resolves the contradiction by decoupling the selection discreteness from the optimization continuity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If a non-differentiable gating mechanism is used in MoE networks, then sparse expert selection is achieved, but efficient training methods such as gradient-based optimization become impossible

Engineering Contradiction:
Improvesparse expert selection efficiencyVSAvoidtraining feasibility
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent changes the parameter representation from discrete indicators to continuous values with binary encoding. The gating mechanism uses continuous probabilities combined with binary encoding to represent discrete expert selections, enabling gradient-based optimization. This parameter transformation allows the system to maintain sparse selection efficiency while making the training process feasible through standard gradient descent methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical discrete selection system with a continuous mathematical system that supports differentiation. Instead of using non-differentiable operations like argmax or hard selection, the system employs softmax functions and continuous relaxation techniques that substitute the discrete mechanical selection process with a differentiable mathematical framework, enabling efficient gradient-based training.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If computational capacity is increased by using more expert neural networks, then performance on machine learning tasks improves, but computing resource requirements increase

Engineering Contradiction:
Improveperformance on machine learning tasksVSAvoidcomputing resources
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the computational workload by dividing it into multiple expert neural networks that can be selectively activated. Instead of using all expert networks for every input, the sparse gating mechanism segments the computation to only the necessary subset of experts, reducing the actual computing resources consumed while maintaining the potential for high performance through selective engagement of specialized experts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by activating only a small number of expert networks out of the total available experts for each input. This partial engagement strategy allows the system to have access to large computational capacity (excessive potential action) while actually consuming only the necessary computing resources (partial actual action) to achieve state-of-the-art performance on machine learning tasks.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12518135B2Sparse and differentiable mixture of experts neural networks
Publication Date: 2026.01.06 GOOGLE LLC
  • US12518135B2 patent drawing
  • US12518135B2 patent drawing
  • US12518135B2 patent drawing

AI summary

A system including a main neural network for performing one or more machine learning tasks on a network input to generate one or more network outputs. The main neural network includes a Mixture of Experts (MoE) subnetwork that includes a plurality of expert neural networks and a gating subsystem. The gating subsystem is configured to: apply a softmax function to a set of gating parameters having learned values to generate a respective softmax score for each of one or more of the plurality of expert neural networks; determine a respective weight for each of the one or more of the plurality of expert neural networks; select a proper subset of the plurality of expert neural networks; and combine the respective expert outputs generated by the one or more expert neural networks in the proper subset to generate one or more MoE outputs.