接触回転系におけるパターン形成現象

（逐次計算式の切り替えによる安定判別）

抄録

Pattern formation phenomena due to time delay often occur in contact rotating systems. In the previous study, we have established a stability analysis method based on the existence condition in stable and unstable boundary in not only the system with a single time delay but also the system with multiple time delays. In case of the system with a single time delay, it is possible to obtain large amount of information in small amount of calculation time since the fundamental equations are expressed as the generalized eigenvalue problem. However, in case of the system with multiple time delays, calculation time is increased, because another method, for example Newton's method, is required to solve the fundamental equations. To reduce the calculation time, we have proposed iterative calculation method which divides the fundamental equations into equations with small dimensions. However, the proposal method was not applicable when the number of polygons is increased. Therefore, in this report, we improved the iterative calculation method by switching a formula to be solved. In addition, we verify the accuracy of the improved method and compare it with the conventional method in calculation time.