ACCELERATION AND PARALLELIZATION OF ARBITRARY TRAJECTORY BASED THREE-DIMENSIONAL METHOD OF CHARACTERISTICS

The method of characteristics based on arbitrary trajectory adopts interpolation method to deal with the reflective boundary, which can break the restriction on the choice of trajectory layouts and quadrature sets. An acceleration and parallelization scheme is used to reduce the computational time. A generalized coarse-mesh finite difference (GCMFD) method which can be performed on generalized geometry is applied for acceleration. To effectively accelerate, we extend a single GCMFD method to the two-level GCMFD method, one level for the spatial acceleration and the other for the energy group acceleration. On the other hand, a parallelization method based on message-passing model uses an angular decomposition scheme. By grouping the directions to satisfy the reflective relation can effectively reduce the data communications. The numerical results show a good performance on reducing the number of iterations and speeding up the code after the acceleration and parallelization.