Circuit Partitioning Divides circuit into smaller partitions that

can be efficiently handled Goal is generally to minimize

communication between balanced partitions

Kernighan-Lin Fiduccia-Mattheyses (KLFM) is popular algorithm

KLFM Algorithm Basic Idea:

Start with initial partition Iteratively improves cutsize

Cutsize is number of edges between partitions Moves one node at a time

Node that gives greatest reduction or least degradation Lock node after moving Continue moving nodes until all locked or size

contraints are violated Find best partitioning, unlock all nodes Repeat until no improvement found

KLFM AlgorithmInitial Partition

Cutsize = 5

Size = 3 Size = 3Maximum Size = 4

KLFM Algorithm

Cutsize = 3

Size = 4 Size = 2Maximum Size = 4

KLFM Algorithm

Cutsize = 2

Size = 3 Size = 3Maximum Size = 4

KLFM Algorithm

Cutsize = 2

Size = 2 Size = 4Maximum Size = 4

KLFM Algorithm

Cutsize = 4

Size = 3 Size = 3Maximum Size = 4

KLFM Algorithm

Cutsize = 4

Size = 2 Size = 4Maximum Size = 4

KLFM Algorithm

Cutsize = 5

Size = 3 Size = 3Maximum Size = 4

KLFM Algorithm

Cutsize = 2

Size = 3 Size = 3

Backtrack to minimum cut size, unlock nodes, and repeat