Handling Orientation and Aspect Ratio of Modules in Electrostatics-based Large Scale Fixed-Outline Floorplanning

In this paper, we present an improved electrostatics-based analytical method for fixed-outline floorplanning, which incorporates module rotation and sizing driven by wirelength. To accurately compute the density function after module rotation, we propose a novel density calculation algorithm based on line drawing and polygon clipping algorithms commonly used in computer graphics. By using this algorithm, we are able to accurately compute the density function after module rotation without adding any complexity. Moreover, we propose a module legalization algorithm by adding module sizing and module rotation after the existing constraint graph adjustment step. Furthermore, we adopt a linear programming to minimize wirelength to improve the quality of the results. Experimental results demonstrate that our floorplanning algorithm achieves at least 5.9% and 11% reduction in half-perimeter wirelength on the HB+ and ami49_x benchmarks, respectively, compared to state-of-the-art floorplanners.