Neural Network Subgroup Scaling for Accuracy

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Solution Overview

Problem

Deep Neural Networks (DNNs) face challenges in deployment due to increasing memory and computational footprints, particularly in constrained hardware environments, where Binarized Neural Networks (BNNs) and Ternary Neural Networks (TNNs) suffer from significant accuracy drops on challenging datasets.

Innovation Solution

The implementation of a neural network system that uses subgroups for weights based on locality, applying irregular scaling coefficients on one or two dimensions of a weight space, which improves prediction accuracy without significantly increasing hardware complexity, and enables high data parallelism for both binary and ternary networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If Binarized Neural Networks (BNNs) and Ternary Neural Networks (TNNs) are used to reduce memory and computational footprints, then hardware complexity is reduced, but prediction accuracy drops significantly

Engineering Contradiction:
Improvehardware complexityVSAvoidprediction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by introducing subgroup-specific scaling coefficients that operate locally on different regions of the weight space. Instead of using a single global scaling factor, the weight space is divided into subgroups (e.g., along different dimensions of the kernel filter or input feature map), and each subgroup receives its own scaling coefficient. This local adaptation allows the system to maintain higher prediction accuracy while still using binarized or ternary weights, as each local region can be optimized independently to compensate for the quantization effects.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If DNN size increases to improve prediction capabilities, then prediction accuracy improves, but memory and computational footprints increase

Engineering Contradiction:
Improveprediction accuracyVSAvoidmemory footprint
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes the parameters of the neural network representation by introducing scaling coefficients that modify the effective weight values. By applying these scaling coefficients to subgrouped weights, the system can achieve better approximation of full-precision weights without increasing the actual number of stored parameters. The scaling coefficients are learned during training and allow the binarized/ternary network to adapt its parameter distribution to maintain accuracy while using fewer bits per weight.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If DNN size increases to improve prediction capabilities, then prediction accuracy improves, but computational footprint increases

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational footprint
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the weight space into multiple subgroups based on spatial or functional criteria. This segmentation allows the computational operations to be organized in a structured manner where scaling coefficients are applied to specific subgroups rather than all weights uniformly. The segmentation enables efficient parallel computation and reduces the computational overhead by localizing the scaling operations to relevant weight subsets, thereby improving accuracy without proportionally increasing the overall computational footprint.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11615300B1System and method for implementing neural networks in integrated circuits
Publication Date: 2023.03.28 XILINX INC
  • US11615300B1 patent drawing
  • US11615300B1 patent drawing
  • US11615300B1 patent drawing

AI summary

A neural network system includes an input layer, one or more hidden layers, and an output layer. A first layer circuit implements a first layer of the one or more hidden layers. The first layer includes a first weight space including one or more subgroups. A forward path circuit of the first layer circuit includes a multiply and accumulate circuit to receive an input from a layer preceding the first layer; and provide a first subgroup weighted sum using the input and a first plurality weights associated with a first subgroup. A scaling coefficient circuit provides a first scaling coefficient associated with the first subgroup, and applies the first scaling coefficient to the first subgroup weighted sum to generate a first subgroup scaled weighted sum. An activation circuit generates an activation based on the first subgroup scaled weighted sum and provide the activation to a layer following the first layer.