※ 引述《tellux (寒川凝步)》之銘言： : //TU190 : In this paper, the author presents a detailed placement algorithm that : can handle both row-based standard cell placement and placement in : presence of fixed macros. This detailed placer works on legalized : placement to further improve the solution quality. It consists of a : Global Swap technique to swap cells based on their optimal region, a ^^^^^^^^^^^^^^^^^^^^ regions?, each cell has it's own optimal region : Vertical Swap technique to fix the local errors vertically, a fast : Local Re-ordering technique to fix the local order horizontally, and : a Single-Segment Clustering technique that can place the cells in a : segment optimally when cells not in this segment are fixed. Experiments ^^^^, and the ("not in this segment" is specified) : on two sets of benchmarks show that this detailed placer can achieve : better wirelength and runtime compared to Fengshui 5.0, rowIroning : and Domino. : 1. The author claims four main contributions in this paper: Global : Swap, Vertical Swap, Local Re-ordering, and Single-Segment Clustering. : However, three of these ideas (Global Swap, Local Re-ordering, and : Single-Segment Clustering) are very similar to those in the detailed : placement of "FastPlace: An Analytical Placer for Mixed-Mode Designs" : published in ISPD05. This paper just contributes more implementation : details about these ideas and provides a faster algorithm for : Fixed-Order Single Segment Placement Problem. : 2. The experimental results in this paper may not be an appropriate : comparison. The author used the Placement Utilities in Capo9.1 to : legalize MPL5's global placement result. The placement result was : too much disturbed by the legalizer and shouldn't be used to compare shouldn't be compared to ^^ : the performance of detailed placer. The legalized wirelength by : MPL5's own legalizer is 1.70e+06, which is even better then the : wirelength (1.78e+06) result generated by the detailed place stated : in this paper. The claim in the abstract (a legalized state-of-the-art : global placement solution may still have a lot of room for : improvement in wirelength) is not appropriate. ^^^^^^^^^^^ N-count : 3. The paper claims that Global Swap gives the result most profit, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ "the most" ，這句話有點奇怪，給了result 最多的profit? 感覺不是很英文 : but there isn't any experimental result in this. The readers cannot : distinguish the individual contributions of the algorithms proposed : in this paper. : //HI112 : A three-step mixed-size detailed placement is described in this paper. : A combination of constraint graph and linear programming is used to : remove the overlap between macros. Standard cells are legalized by : an enhanced greedy method. In the end, a slidingwindow-based cell : swapping is applied to further reduce wirelength. The experimental : results show that it can produce legal placement for all the circuits : in ICCAD04-MS, while Fengshui fails for 1/3 of them, and the : wirelength produced using its algorithm is shorter by 3% on average. : 1. The paper proposes a macro legalization method with a combination : of constraint graph and linear programming. However, the experimental : results show very little wirelength improvement compared with a : simple greedy legalizer. The author claimed the method one of the : two main contributions, which does not seem an efficient way to macro : legalization. : 2. The paper claims that it can produce legal placement for all the : circuits in ICCAD04-MS, while Fengshui fails for 1/3 of them. This ^^^不用 prep吧? Obi-wan 對Annakin 說 "I failed you" : is not a fair comparison while the global placement results are : generated by an unknown analytical placer. Why not just use Fengshui's : global placement result for comparison? The experimental results will : be much more convincing if the proposed method could generate better : result on Fengshui's global placement compared with Fengshui's own a better result/results : detailed placer. -- 拒絕人最好的方法就是慢慢讓他失去希望，或是讓他忘了他一開始 到底想要什麼... --

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