Boolean Satisfiability Circuit Accelerator Using Analog Constraints

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Solution Overview

Problem

Current algorithms for Boolean satisfiability (SAT) problems have exponential worst-case complexity, leading to prolonged runtime in hardware and software verification, limiting the development of capable autonomous systems and degrading results, as they are NP-complete and difficult to solve efficiently on digital computers.

Innovation Solution

An analog circuit arrangement with a constraints network and configurable switch array that randomly or pseudo-randomly flips values of Boolean variables until they stabilize, enforcing clauses defined by Boolean variables and their negations, transforming the SAT problem into an optimization problem to avoid local minima and find satisfying solutions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional digital algorithms are used to solve SAT problems, then the approach is computationally exhaustive, but the runtime becomes exponential and impractically long

Engineering Contradiction:
Improvecorrectness of SAT solutionVSAvoidSAT runtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces conventional digital computational algorithms with an analog circuit system that uses continuous voltage signals and physical circuit dynamics to solve SAT problems. The analog circuit uses voltage thresholds and circuit states to represent Boolean variables and clauses, enabling parallel physical computation that avoids the exponential runtime of digital algorithms while maintaining solution correctness.

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

Solution Approach 2:

The patent transforms the discrete Boolean variable representations into continuous voltage parameters within the analog circuit. By using voltage levels to represent logical values and utilizing the continuous dynamics of the circuit (including random flipping mechanisms), the system changes the computational parameter space from discrete digital states to continuous analog states, enabling faster convergence to solutions.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If SAT problems are solved using standard algorithms, then complete verification is achieved, but the complexity increases exponentially for large problems

Engineering Contradiction:
Improveverification completenessVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the SAT problem into discrete clause components that are independently processed by separate circuit modules. Each clause is represented by a dedicated circuit section that can be satisfied independently, allowing the complex verification task to be segmented into manageable parallel operations that reduce overall computational complexity while maintaining completeness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional physical dimension by using continuous voltage dynamics and analog circuit behavior to solve the SAT problem. Instead of relying solely on discrete logical operations that scale exponentially, the analog dimension provides continuous state space exploration and parallel processing capabilities that reduce computational complexity for large-scale verification.

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

3Productivity

If random flipping of variable values is used to escape local minima, then the search space is explored more effectively, but the process may continue indefinitely without stabilization

Engineering Contradiction:
Improvesolution finding speedVSAvoidflipping process duration
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent incorporates feedback mechanisms in the analog circuit that continuously monitor clause satisfaction and variable states. The circuit uses this feedback to dynamically adjust voltage levels and switching behavior, enabling the system to detect when variable values have stabilized and to terminate the random flipping process appropriately, thus combining effective search space exploration with controlled termination.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements periodic evaluation cycles where the circuit systematically flips variable values in alternating phases. This periodic action allows the system to alternate between exploration (random flipping) and exploitation (stabilization detection), creating a rhythmic search pattern that efficiently navigates the solution space while avoiding indefinite operation through built-in termination conditions.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS20240111824A1Boolean satisfiability circuit accelerator
Publication Date: 2024.04.04 UNIV OF SOUTHERN CALIFORNIA
  • US20240111824A1 patent drawing
  • US20240111824A1 patent drawing

AI summary

A circuit arrangement includes an array of switches that represent a Boolean satisfiability expression that has a plurality of clauses each defined by a combination of Boolean variables Xi or ¬Xi, a first plane, and a constraints network operatively arranged with the first plane. The constraints network enforces each of the clauses such that values of different ones of the variables continue to randomly or pseudo randomly flip until the values of the variables Xi and ¬Xi stop changing or a predetermined condition occurs.