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FAR: Fixed Points Addition & Relaxation Based Placement

FAR: Fixed Points Addition & Relaxation Based Placement. Bo Hu and Malgorzata Marek-Sadowska University of California, Santa Barbara. Outline. Introduction Previous works Fixed points Addition & Relaxation(FAR) Experimental results Conclusion. Simulated Annealing. Quadratic.

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FAR: Fixed Points Addition & Relaxation Based Placement

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  1. FAR: Fixed Points Addition & Relaxation Based Placement Bo Hu and Malgorzata Marek-Sadowska University of California, Santa Barbara

  2. Outline • Introduction • Previous works • Fixed points Addition & Relaxation(FAR) • Experimental results • Conclusion

  3. Simulated Annealing Quadratic Partitioning Partitioning Constant force FAR AR model Introduction Placement Methodology

  4. Introduction cont. Placement Category Global Placement Detailed Placement Incremental Placement FAR

  5. Previous Works • Constant Force • “Generic Global Placement and Floorplanning”, Hans Eisenmann and Frank M. Johannes, DAC98. • Attractor-Repeller Model • “Attractor-Repeller Approach for Global Placement”, Hussein Etawil, Shawki Areibi, and Anthony Vannelli, ICCAD-99.

  6. Constant Force (EQ1) (EQ2) (EQ3) (EQ4) Vector e is constant force based on density.

  7. Fixed Point • A fixed point p(x, y) is a dimensionless pseudo cell positioned at (x,y) on the chip plane. • Fixed point can be anywhere, not necessarily within the chip boundary. • Connectivity between fixed points and real cells can be dynamically modified. (EQ5)

  8. Controlling Fixed point Category-I: controlling fixed points • Controlling fixed points are used to maintain force equilibrium state.

  9. Category-II: Perturbing fixed points • Perturbing fixed points are used to transform the placement Perturbing fixed point Perturbing fixed point Perturbing fixed point

  10. Category-III: Constraining fixed points • Constraining fixed points are used to restrict the movement of cells. constraining fixed point constraining fixed point constraining fixed point

  11. Apply FAR in global placement – one transform CF initial FAR

  12. FAR based incremental placement • Buffer Site Generation(BSG)

  13. Apply FAR in BSG Controlling Fixed point Perturbing fixed point Constraining fixed point

  14. Experimental results for global placement – wire length

  15. Experimental results for global placement – CPU time for one transformation

  16. Experimental results for BSG – test cases

  17. Experimental results for BSG – CF vs. FAR

  18. Experimental results for BSG

  19. Conclusion • FAR based placement approach can be applied in both global placement( overlapping elimination ) and incremental placement (Buffer Site Generation) contexts. • FAR is quadratic-solver friendly approach.

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