Andrew Kemp (LSU), Carola Kaiser (LSU), Robert Twilley (Sea Grant @LSU), Hartmut Kaiser (LSU )

1. ADCIRC Surge Guidance System (ASGS) / Coastal Emergency Risks Assessment (CERA) NSF Grant 1010640 Shape File Contour Line Generation for ADCIRC Data Contour lines are essential for the mapping and comprehension of hurricane data. However, generating contour lines from large pools of data takes significant time when executed serially. Students at Louisiana State University's Center for Computation and Technology (LSU CCT) have addressed this by using the HPX framework to generate contour lines on multiple cores simultaneously. This parallelization insures output data will be visualized quickly and enables the frequent assessment of forecasts and algorithms. • Written in C++ • Uses the HPX framework for multiprocessing • Implements a k-d tree with Boost data structures • Thread-safe under all conditions • Very efficient and scales almost linearly The ADCIRC domain* is read from an external file and then the contour threads are queued with one thread running for every chosen height. A shared pointer is provided to each contour thread to read the mesh. A unique pointer to corresponding to a unique vector in the main thread is passed to every contour thread. This operation is thread-safe because a separate vector is used by each thread. The line segments are generated by passing a plane for the assigned contour height through every triangle in the lattice. This operation occurs while the triangles are being input from the memory. After each triangle has been processed, the individual segments are added to a k-d tree and radial search determines which endpoints are close enough to be connected. The thread is only terminated after adjacent endpoints are not found after processing the entire set of endpoints. * The ADCIRC domain is characterized by a lattice of triangles defined by elements and nodes. The nodes have multiple attributes which may represent any arbitrary form of data, with two attributes usually corresponding to spatial data. These two attributes represent the geographical longitude and latitude in our implementation, serving as x and y coordinates respectively. An additional user-defined attribute serves as the z-coordinate, in this case the elevation of a node. Elements in groups of three represent the indices of the nodes used to create the triangles. One node can be used by many triangles but one element is only used by one triangle as one of its three vertices. Results Performance Andrew Kemp (LSU), Carola Kaiser (LSU), Robert Twilley (Sea Grant @LSU), Hartmut Kaiser (LSU) Storm-Induced Water Levels Entire Mesh Florida Coast