Fixed Point Approximation via Segmented Taylor Series

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Solution Overview

Problem

Conventional methods for approximating power functions using fixed-point arithmetic in electronic devices are complex, requiring large memory and processing resources, and offer limited accuracy, especially in applications involving high-definition media processing.

Innovation Solution

A novel method combining table lookup with Taylor series approximation, utilizing small tables and minimal arithmetic operations to efficiently compute power functions, allowing for a large domain and reasonable accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Taylor series approximation is used to compute power functions, then processing speed is improved, but accuracy deteriorates when input values are not close to the expansion point

Engineering Contradiction:
Improveprocessing speedVSAvoidapproximation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides the domain of the power function into multiple segments, each centered around a convenient expansion point. By segmenting the input range, the system ensures that any input value falls within a segment where Taylor series approximation maintains high accuracy, thus resolving the contradiction between processing speed and accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically changes the expansion point parameter based on the input value's location within different segments. This allows the Taylor series to be centered at optimal points for each segment, maintaining accuracy across the entire domain while preserving the computational efficiency of the series approximation method.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If Newton-Raphson method is used to compute power functions, then accuracy is improved, but device complexity increases due to processing power requirements

Engineering Contradiction:
Improveapproximation accuracyVSAvoidprocessing power requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by using Taylor series approximation with a limited number of terms rather than the full iterative Newton-Raphson method. This provides sufficient accuracy for the application while significantly reducing the processing power requirements and device complexity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent uses computationally inexpensive Taylor series calculations that can be performed with simple arithmetic operations, replacing the more complex and resource-intensive Newton-Raphson iterations. This approach achieves adequate accuracy with much lower computational cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If table lookup method is used to store pre-computed values, then processing speed is improved, but memory requirements increase proportionally with the domain size

Engineering Contradiction:
Improveprocessing speedVSAvoidmemory space
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the large lookup table into multiple smaller tables, each covering a specific segment of the domain. This segmentation reduces the memory footprint of each individual table while maintaining comprehensive coverage of the entire domain through the segmented structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional dimension by organizing the lookup data into a hierarchical structure with multiple levels. This dimensional reorganization allows efficient access to pre-computed values while reducing the total memory required compared to a single flat table.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8356066B1System and method for generating a fixed point approximation to nonlinear functions
Publication Date: 2013.01.15 GEO SEMICONDUCTOR INC
  • US8356066B1 patent drawing
  • US8356066B1 patent drawing
  • US8356066B1 patent drawing

AI summary

A system and method are provided for use in an electronic device configured to process data to perform a method of generating a fixed point approximation of a number x by first locating the most significant bit of a given number, then retrieving predetermined values from electronic data storage, where the first value is based on a first index value generated from the most significant bit and contains fixed-point representation located in a table in storage. Then, output values are generated from look-up tables that correspond to index values generated from a number of bits that immediately following the most significant bit. Finally, the final mathematic result is computed using fixed-point arithmetic logic to generate a fixed point approximation.