Posit Memory Array Layout for Dynamic Range and Numerical Precision

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Solution Overview

Problem

Current memory systems face limitations in performing calculations due to finite memory resources, particularly in representing and processing numerical data, where formats like floating-point struggle with accuracy, precision, and dynamic range, leading to issues like overflow, underflow, and increased processing time.

Innovation Solution

The implementation of a universal number format known as 'posit' which allows for greater dynamic range and accuracy than traditional floating-point formats, using a format with four sets of bits (sign, regime, exponent, and mantissa) that can be reconfigurable for improved performance in computing systems, especially in machine learning applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If floating-point format is used to store numerical data, then dynamic range is provided, but accuracy and precision are limited leading to overflow and underflow issues

Engineering Contradiction:
Improvenumerical accuracyVSAvoiddynamic range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The posit format segments the numerical representation into four distinct bit fields: sign bit, regime bits, exponent bits, and mantissa bits. This segmentation allows each component to be optimized independently - the regime bits handle precision for numbers near 1, the exponent bits extend dynamic range, and the mantissa bits provide additional precision, thereby resolving the contradiction between accuracy and dynamic range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The posit format introduces reconfigurability through variable-length regime and exponent fields that can be adjusted based on the magnitude of the number being represented. This dynamic allocation of bits allows the format to adapt to different numerical ranges and precision requirements, simultaneously achieving high accuracy and extended dynamic range without the overflow/underflow problems of traditional floating-point formats.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If more bits are used to increase accuracy and precision, then numerical representation improves, but memory requirements increase

Engineering Contradiction:
Improvenumerical precisionVSAvoidmemory resources
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The posit format changes the parameters of numerical representation by using a non-fixed allocation of bits across different fields. Instead of dedicating fixed numbers of bits to exponent and mantissa as in IEEE 754, posit allows the regime and exponent fields to vary in length based on the number's magnitude, enabling high precision to be achieved with fewer total bits for many practical cases, thereby reducing memory requirements while maintaining or improving numerical precision.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If traditional floating-point formats are used, then memory resources are consumed, but processing time increases due to limited dynamic range and accuracy

Engineering Contradiction:
Improveprocessing speedVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The posit format performs preliminary optimization of the numerical representation structure before processing operations. By pre-configuring the regime, exponent, and mantissa fields according to the number's characteristics, the format eliminates the need for complex runtime adjustments and special-case handling that plague traditional floating-point arithmetic, thereby reducing processing time and improving productivity in computational operations.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11403067B2Memory array data structure for posit operations
Publication Date: 2022.08.02 MICRON TECHNOLOGY INC
  • US11403067B2 patent drawing
  • US11403067B2 patent drawing
  • US11403067B2 patent drawing

AI summary

Systems, apparatuses, and methods related to a memory array data structure for posit operations are described. Universal number (unum) bit strings, such as posit bit string operands and posit bit strings representing results of arithmetic and/or logical operations performed using the posit bit string operands may be stored in a memory array. Circuitry deployed in a memory device may access the memory array to retrieve the unum bit string operands and/or the results of the arithmetic and/or logical operations performed using the unum bit string operands from the memory array. For instance, an arithmetic operation and/or a logical operation may be performed using a first unum bit string stored in the memory array and a second unum bit string stored in the memory array. The result of the arithmetic operation and/or the logical operation may be stored in the memory array and subsequently retrieved.