Jarmo Rantakokko

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The educational impact of visualization depends not only on how well students learn when they use it, but also on how widely it is used by instructors. Instructors believe that visualization helps students learn. The integration of visualization techniques in classroom instruction, however, has fallen far short of its potential. This paper considers this(More)
On cc-NUMA multi-processors, the non-uniformity of main memory latencies motivates the need for co-location of threads and data. We call this special form of data locality, geographical locality. In this article, we study the performance of a parallel PDE solver with adaptive mesh refinement. The solver is parallelized using OpenMP and the adaptive mesh(More)
This is a status report of a long-term research eeort focusing on object-oriented modeling of parallel PDE solvers, based on nite diierence methods on composite, structured grids. Two previous results of this eeort are reviewed, the class libraries Cogito and Compose. Cogito is implemented in Fortran 90, with MPI for the message passing, and provides(More)
OpenMP is an architecture-independent language for programming in the shared memory model. OpenMP is designed to be simple and powerful in terms of programming abstractions. Unfortunately, the architecture-independent abstractions sometimes come with the price of low parallel performance. This is especially true for applications with unstructured data(More)
The performance of shared-memory (OpenMP) implementations of three different PDE solver kernels representing finite difference methods, finite volume methods, and spectral methods has been investigated. The experiments have been performed on a self-optimizing NUMA system, the Sun Orange prototype, using different data placement and thread scheduling(More)
We present an integrated domain decomposition and data partitioning approach for irregular block-structured methods in scien-tiic computing. We h a ve demonstrated the method for an application related to Ocean modeling. Our approach gives better results than other methods that we have found in the literature. We h a ve compared the domain decomposition(More)