Rectilinear Steiner Minimum Tree Wire Length Optimization

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Solution Overview

Problem

Conventional rectilinear Steiner minimum tree algorithms face inflexibility in designs with pre-routes and struggle to accommodate sink-driver constraints, limiting their ability to optimize wire lengths in integrated circuit design.

Innovation Solution

The development of algorithms that calculate candidate connections between terminal nodes and store them in a node heap to determine the minimum Steiner tree, allowing for the inclusion of pre-defined connections and Steiner nodes to optimize wire routing, thereby addressing the limitations of existing methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional RSMT algorithms (FLUTE, node-breaking) are used to minimize wire lengths, then wire length optimization is achieved, but inflexibility in designs with pre-routes occurs

Engineering Contradiction:

Improvewire lengthVSAvoidflexibility with pre-routes

Core Design Contradiction:

Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The algorithm dynamically adjusts its behavior based on the presence of pre-routes. When pre-routes are detected, the algorithm modifies the Steiner tree construction process to accommodate these predefined paths, allowing the solution to adapt between rigid optimization and flexible routing requirements

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The algorithm changes the cost parameters and constraints based on whether pre-routes are present. By modifying the optimization parameters dynamically, the algorithm can switch between pure length minimization and constrained routing that respects pre-defined paths

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If conventional RSMT algorithms are used to create minimum Steiner trees, then wire length optimization is achieved, but sink-driver constraints cannot be accommodated

Engineering Contradiction:

Improvewire lengthVSAvoidaccommodation of sink-driver constraints

Core Design Contradiction:

Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The algorithm segments the routing problem into distinct components: terminal nodes, pre-routes, and sink-driver constraints. By processing these segments separately and then integrating them, the algorithm can optimize wire lengths while satisfying the additional sink-driver requirements

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The algorithm introduces intermediary nodes and edges that act as mediators between the terminal nodes and the sink-driver constraints. These intermediaries allow the Steiner tree to transition smoothly from length optimization to constraint satisfaction

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8635576B2Method for determining wire lengths between nodes using a rectilinear steiner minimum tree (RSMT) with existing pre-routes algorithm

Publication Date: 2014.01.21 ORACLE INT CORP

AI summary

A method for the creation of rectilinear Steiner minimum trees includes determining a set of candidate connections from a terminal node to a different terminal node or to a graph edge. The length of each candidate connection may be used to determine the set of candidate connections that span the graph with a minimum total length.