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[Keyword] area optimization(2hit)

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  • Efficient Hybrid Grid Synthesis Method Based on Genetic Algorithm for Power/Ground Network Optimization with Dynamic Signal Consideration

    Yun YANG  Shinji KIMURA  

     
    PAPER-Physical Level Design

      Vol:
    E91-A No:12
      Page(s):
    3431-3442

    This paper proposes an efficient design algorithm for power/ground (P/G) network synthesis with dynamic signal consideration, which is mainly caused by Ldi/dt noise and Cdv/dt decoupling capacitance (DECAP) current in the distribution network. To deal with the nonlinear global optimization under synthesis constraints directly, the genetic algorithm (GA) is introduced. The proposed GA-based synthesis method can avoid the linear transformation loss and the restraint condition complexity in current SLP, SQP, ICG, and random-walk methods. In the proposed Hybrid Grid Synthesis algorithm, the dynamic signal is simulated in the gene disturbance process, and Trapezoidal Modified Euler (TME) method is introduced to realize the precise dynamic time step process. We also use a hybrid-SLP method to reduce the genetic execute time and increase the network synthesis efficiency. Experimental results on given power distribution network show the reduction on layout area and execution time compared with current P/G network synthesis methods.

  • Air-Pressure Model and Fast Algorithms for Zero-Wasted-Area Layout of General Floorplan

    Tomonori IZUMI  Atsushi TAKAHASHI  Yoji KAJITANI  

     
    PAPER

      Vol:
    E81-A No:5
      Page(s):
    857-865

    A floorplan is a partition of a rectangle into subrectangles, each of which is associated with a module. Zero-wasted-area layouts are known to exist when the height and width of modules are constrained only by the area, and several methods have been proposed for deriving such layouts. However, because these methods are global and indirect, they are inherently slow. We propose a new algorithm which simulates the air-pressure mechanics. It begins with a layout, which is not necessarily feasible, and iterates the movement of one wall at a time to the force-balancing position. The key issue is that it is guaranteed that every movement makes a current layout approach a zero-wasted-area layout by the measure of energy which is defined here. Experimental results on the example in several literatures and artificially made complex examples showed very fast convergence. The algorithm is evolved to methods which move all the walls simultaneously, resulting in a further speed enhancement.