Implementation of plasma stability code on a Cell cluster system for constant plasma monitoring

Kushida, Noriyuki; Takemiya, Hiroshi

We developed a high-speed eigenvalue solver and a matrix generation code that are essentials of a plasma stability analysis system for nuclear fusion reactors on a Cell cluster system. In order to achieve sustainable operation of the reactors, we must evaluate the state of plasma within the characteristic confinement time. Therefore, we introduced a Cell that has high computational power and high performance/cost. Furthermore, we developed a novel eigenvalue solver, which consumes most of the plasma evaluation time. The eigensolver is based on the CG method and was designed by considering hierarchical parallelism of Cell. Moreover, we developed a new CG acceleration method, called locally complete LU that has both better acceleration and performance than the formers. Finally, we succeeded in obtaining our target performance: we were able to create and solve a block tri-diagonal Hermitian containing 1024 diagonal blocks, where the size of each block was 128128, within two sec.