Adaptive mesh refinement (AMR) is a numerical simulation technique used in computational fluid dynamics (CFD). It permits the efficient simulation of phenomena characterized by substantially varying scales in complexity of local behavior of certain variables. By using a set of nested grids at different resolutions, AMR combines the simplicity of structured rectilinear grids with the possibility...

In data-intensive applications, such as high-energy physics, bioinformatics, we encounter applications involving numerous jobs that access and generate large datasets. Effective scheduling such applications is challenging, due to a need to consider for both computational resources and data storage resources. In this paper, we describe an adaptive scheduling model that consider availability of c...

This paper describes the gridlib project, a unified grid management framework for simulation and visualization. Both, adaptive PDE-solvers and interactive visualization toolkits, have to manage dynamic grids. The gridlib meets the similar but not identical demands on grid management from the two sides, visualization and simulation. One immediate advantage of working on a common grid is the fact...

Common techniques tackling the task of classification in data mining employ ansatz functions associated to training data points to fit the data as well as possible. Instead, the feature space can be discretized and ansatz functions centered on grid points can be used. This allows for classification algorithms scaling only linearly in the number of training data points, enabling to learn from da...

Computational grids are now widespread, but their large-scale behaviour is still poorly understood. We report on some calculations of loading, scaling and utilisation behaviours of computational grids, based on simulations. We employ animat agents on a topologically detailed graph representing a grid overlay network. Agents are used to represent computational jobs, users and resources. We can o...

The solution of elliptic partial differential equations on composite overlapping grids using multigrid is discussed. An approach is described that provides a fast and memory efficient scheme for the solution of boundary value problems in complex geometries. The key aspects of the new scheme are an automatic coarse grid generation algorithm, an adaptive smoothing technique for adjusting residual...

We introduce a new numerical grid-based method on unstructured grids in the three-dimensional real-space to investigate the electronic structure of polyatomic molecules. The Voronoi-cell finite difference (VFD) method realizes a discrete Laplacian operator based on Voronoi cells and their natural neighbors, featuring high adaptivity and simplicity. To resolve multicenter Coulomb singularity in ...

This paper describes a direct solver algorithm for a sequence of finite element meshes that are hrefined towards one or several point singularities. For such a sequence of grids, the solver delivers linear computational cost O(N) in terms of CPU time and memory with respect to the number of unknowns N. The linear computational cost is achieved by utilizing the recursive structure provided by th...

Classic protection schemes for existing distribution systems designed for passive and radial networks have been shown to be inadequate for emerging distribution grids. A new protection paradigm, architecture and philosophy are required in response to changes in behaviour of fault currents. These changes are due to the introduction of distributed generation and flexible network topologies, micro...

Data from computational fluid dynamics (CFD) are frequently computed on curvilinear grids. In contrast to cartesian or uniform grids, the cell size in a curvilinear grid can vary significantly, which in turn complicates filter operations tremendously. Some of these filter operations may for example re-map the value range of the data values into another range. In this paper, we present adaptive ...