Stochastic Memory Write for Neural Network Training

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Solution Overview

Problem

Training and inference processes for artificial neural networks (ANNs) are resource-intensive due to the need for stochastic rounding and error-free memory, which limits their efficiency and accuracy, especially in binary ANNs.

Innovation Solution

Utilizing error-prone memory, such as magnetic random access memory (MRAM), for training and inference by stochastically writing values, eliminating the need for generating stochastic parameter values and reducing the need for error correction, thereby allowing for more efficient storage and classification without significant increases in prediction errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If deterministic rounding is used to store binary ANN parameters in memory, then resource usage (energy and computation) is reduced, but training accuracy deteriorates compared to stochastic rounding

Engineering Contradiction:
Improveenergy usageVSAvoidtraining accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent converts the harmful write errors in error-prone memory into beneficial stochastic rounding effects. By intentionally operating memory at controlled error rates, the previously harmful random write failures become a useful mechanism for generating stochastic rounded values, thereby improving training accuracy while using simpler, more energy-efficient memory hardware.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the operational parameters of error-prone memory by controlling write error rates to specific ranges (e.g., 0.1% to 10%). This parameter adjustment transforms the memory from an unreliable storage device into a controlled stochastic rounding mechanism, enabling accurate binary ANN training with reduced energy consumption.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If error-free memory is used to store ANN parameters, then reliability of parameter storage is improved, but memory density and storage capacity deteriorate due to required redundancy

Engineering Contradiction:
Improveparameter storage reliabilityVSAvoidmemory density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent inverts the traditional approach by not trying to eliminate errors through redundancy, but rather by controlling and utilizing errors as a functional mechanism. Instead of adding redundancy to achieve reliability, the system accepts controlled error rates and uses them for stochastic rounding, thereby achieving both high density and functional reliability.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful aspect of error-prone memory (write errors) into a beneficial feature for stochastic rounding. This eliminates the need for error correction redundancy while maintaining or improving effective reliability for training purposes, thereby increasing memory density.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If stochastic rounding is performed by generating stochastic values before writing to memory, then training accuracy is improved, but resource intensity (computation and energy) increases

Engineering Contradiction:
Improvetraining accuracyVSAvoidresource intensity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the memory system to perform stochastic rounding autonomously during the write operation itself, without requiring external stochastic value generation. The memory's inherent write variability serves the dual purpose of storing values and performing stochastic rounding, eliminating the need for separate random number generation hardware or software.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the stochastic rounding function from the computational domain and transfers it to the memory domain. By generating stochastic effects directly during the memory write process rather than before it, the system eliminates the computational overhead of stochastic value generation while maintaining training accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If conventional memory with error correction is used for ANN inference, then prediction accuracy is maintained, but inference speed and efficiency deteriorate due to error correction overhead

Engineering Contradiction:
Improveprediction accuracyVSAvoidinference speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent converts write errors into beneficial stochastic effects that improve generalization during training. This approach reduces the need for aggressive error correction during inference, as the controlled error model from training makes the network robust to memory errors, thereby improving inference speed without sacrificing accuracy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

5Quantity of substance

If dense memory storage is implemented in error-prone memory, then memory capacity is increased, but the need for redundancy for error correction increases

Engineering Contradiction:
Improvememory capacityVSAvoidredundancy requirements
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent converts the harmful write errors into a useful stochastic rounding mechanism. By controlling error rates and using them intentionally, the system eliminates the need for traditional error correction redundancy, thereby achieving high memory capacity without the overhead of redundancy bits or error correction codes.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11574194B2System and method for training neural networks with errors
Publication Date: 2023.02.07 INTEGRATED SILICON SOLUTION CAYMAN INC
  • US11574194B2 patent drawing
  • US11574194B2 patent drawing
  • US11574194B2 patent drawing

AI summary

A computing device includes one or more processors, random access memory (RAM), and a non-transitory computer-readable storage medium storing instructions for execution by the one or more processors. The computing device receives first data on which to train a neural network comprising at least one quantized layer and performs a set of training iterations to train weights for the neural network. Each training iteration of the set of training iterations includes stochastically writing values to the random access memory for a set of activations of the at least one quantized layer of the neural network using first write parameters corresponding to a first write error rate. The computing device stores trained values for the weights of the neural network. The trained neural network is configured to classify second data based on the stored values.