理化学研究所 計算科学研究センター

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第149回 第4部

第149回 第4部
日時: 2018年10月10日(水)、16:25 - 16:55
場所: R-CCS 6階講堂

・講演題目:Numerical evaluation of preconditioned CG method with higher precision
・講演者:河合直聡 (利用高度化研究チーム 特別研究員)
※発表・スライド共に英語

講演要旨:

Solving large-scale systems of linear equations which has sparse coefficient matrices derived from generalized eigenvalue problems are challenging for iterative solvers. Although the coefficient matrices have ill-conditioned, eigenvalue solvers require higher accuracy of approximate solutions. In this study, we evaluate an effect of a higher precision of a Krylov subspace method with a parallel ILU preconditioner. The ILU preconditioner with regularizations and multi-coloring parallelism showed higher robustness and good performance. To achieve higher accuracy and convergence, we applied quad precision to an IC-COCG method. In this talk, we will have a discussion about the accuracy, convergence ratio and computational time among single, double and quad precisions of the IC-COCG method with well and ill-conditioned problems.