@article{oai:niigata-u.repo.nii.ac.jp:00001713,
 author = {Guo, P. N. and Takahashi, T. and Cheng, C. K. and Yoshimura, T.},
 issue = {2},
 journal = {IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems},
 month = {Feb},
 note = {We present an ordered tree (O tree) structure to represent nonslicing floorplans. The O tree uses only n(2+[lg n]) bits for a floorplan of n rectangular blocks. We define an admissible placement as a compacted placement in both x and y directions. For each admissible placement, we can find an O-tree representation. We show that the number of possible O-tree combinations is O(n!22n-2/nl.5). This is very concise compared to a sequence pair representation that has O((n!)2) combinations. The approximate ratio of sequence pair and O-tree combinations is O(n2(n/4e)n). The complexity of O tree is even smaller than a binary tree structure for slicing floorplan that has O(n!25n-3/n1.5) combinations. Given an O tree, it takes only linear time to construct the placement and its constraint graph. We have developed a deterministic floorplanning algorithm utilizing the structure of O tree. Empirical results on MCNC (www.mcnc.org) benchmarks show promising performance with average 16% improvement in wire length and 1% less dead space over previous central processing unit (CPU) intensive cluster refinement method},
 pages = {281--289},
 title = {Floorplanning using a tree representation},
 volume = {20},
 year = {2001}
}