— This paper presents a new hybrid linear equation solver for quadratic placement. The new solver is a combination of stochastic solver and iterative solver: it is proven in this paper that an approximate LDL factorization can be obtained from random walks, and used as a preconditioner for conjugate gradient solver. Testing on real-life placement benchmarks shows a speedup of up to 7.1 times over traditional Incomplete Cholesky preconditioned Conjugate Gradient (ICCG).
Haifeng Qian, Sachin S. Sapatnekar