High Speed Eigenvalue Solver on the Cell Cluster System for Controlling Nuclear Fusion Plasma

In this study, we developed a high speed eigenvalue solver that is the necessity of plasma stability analysis system for International Thermo-nuclear Experimental Reactor (ITER) on Cell cluster system. Our stability analysis system is developed in order to prevent damages to the ITER from plasma disruption. MARG2D, which is the main part of the system, analyzes the state of plasma with the measured conditions instantaneously. According to our estimation, the most time consuming part of MARG2D is eigensolver and we must solve resulted eigensystem whose dimension is hundred thousand within a second. However, current massively parallel processor (MPP) type supercomputer is not applicable for such instantaneous calculation, because the overhead of network communication becomes dominant. Therefore, we employ Cell cluster system, whose processor has higher performance than MPP´s, because we can obtain sufficient processing power with small number of processors. Furthermore, we developed novel eigenvalue solver with the consideration of hierarchical architecture of Cell cluster: Inter processor, intra processor, and SIMD parallelism. Finally, we succeeded to solve the block tridiagonal Hermitian matrix, which had 1024 diagonal blocks and the size of each block was 128 × 128 within a second.