Graph Coloring Algorithm for LVS Root Cause Identification

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Solution Overview

Problem

Current layout versus schematic (LVS) analysis tools struggle to accurately identify the root cause of errors in circuit designs, often requiring manual tracing by designers, which is time-consuming and inefficient, especially in complex circuits.

Innovation Solution

Implementing a graph coloring algorithm that compares circuit schematic and layout graphs to identify mismatches, followed by a second coloring algorithm to trace back and automatically determine the root cause of errors by propagating node values from mismatched nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If LVS analysis tools report error locations, then error detection capability is improved, but the ability to identify root cause deteriorates because reported locations may be far from the actual error source

Engineering Contradiction:

Improveerror detection accuracyVSAvoidroot cause location information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces an intermediary process between error detection and root cause identification. The system uses a graph coloring algorithm as a mediator that propagates color values from mismatched nodes through the circuit graph to trace back the origin of errors, thereby bridging the gap between where errors are detected and where they actually originate.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the one-dimensional error location reporting into a multi-dimensional analysis by using graph coloring that propagates through multiple nodes and layers of the circuit. This dimensional expansion allows the system to not only identify where errors occur but also trace through the circuit topology to find the root cause in a different dimensional space of the circuit graph.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If manual tracing is performed to locate root cause, then root cause identification accuracy is improved, but time consumption and designer effort increase significantly

Engineering Contradiction:

Improveroot cause identification accuracyVSAvoiddebugging time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements self-service by automating the root cause identification process. Instead of requiring designers to manually trace through circuits, the system automatically performs graph coloring algorithms that propagate node values and identify error origins, enabling the tool to serve itself in finding root causes without human intervention.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical manual tracing process with an automated computational algorithm. The graph coloring algorithm substitutes the physical act of designers manually following circuit connections with an automated digital process that efficiently propagates information through the circuit graph and identifies root causes algorithmically.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If automated root cause identification is implemented, then productivity is improved, but algorithm complexity increases

Engineering Contradiction:

Improveerror debugging speedVSAvoidalgorithm complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the parameters of the analysis by using graph coloring values as a transformation of the circuit representation. Instead of working directly with complex circuit topology and connections, the system transforms the problem into a coloring parameter space where error propagation can be systematically tracked through simplified color value assignments and comparisons.

Inventive Principle:

Principle #35Parameter changes

4Extent of automation

If graph coloring algorithm is used to trace root cause, then automation extent is improved, but computational resources required increase

Engineering Contradiction:

Improveroot cause tracing automationVSAvoidcomputational energy

Core Design Contradiction:

Extent of automationVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by performing graph coloring propagation only on the relevant portions of the circuit graph affected by mismatches. Instead of analyzing the entire circuit, the system focuses computational resources on propagating colors from specific mismatched nodes through their connected subgraphs, reducing unnecessary computational overhead while maintaining automation.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10970456B1Identifying root cause of layout versus schematic errors

Publication Date: 2021.04.06 SYNOPSYS INC

AI summary

A layout versus schematic (LVS) tool identifies a detected mismatch between a first graph representing a circuit layout and a second graph representing a circuit schematic. The detected mismatch is a device or net represented by a first node in the first graph and a corresponding second node in the second graph. The LVS tool assigns a first value to the first node and to the second node. The LVS tool iterates through nodes in the first graph and nodes in the second graph to assign values based on the first value, according to a graph coloring algorithm, until reaching a third node of the first graph and a corresponding fourth node of the second graph that are assigned different values. The LVS tool generates an output identifying the third node and the fourth node as a root cause of the detected mismatch.