1. XLAB Research 2003 – 2006Ljubljana / Slovenia "River Socha Project" Visualization of massive amount of data with Grid based engine Authors: Marjan Šterk, Ivan Leben, Gregor Pipan Organisation: XLAB Research E-mail: marjan.sterk@xlab.simarjan.sterk@xlab.si Cracow Grid Workshop 2006

2. XLAB Research 2003 – 2006Ljubljana / Slovenia Agenda XLAB Company Visualization, algorithms used Distribution of computation, domain decomposition Conclusions

3. XLAB Research 2003 – 2006Ljubljana / Slovenia XLAB Company, Ljubljana, Slovenia Medical Imaging Network & Communication Distributed and grid computing research Main grid-related projects: XtreemOS (FP6 IP) DeDiSys (FP6 STREP) Interactive visualization of flooding areas (national) Computational Grid technologies for better resource utilisation (national) XLAB - Research

4. XLAB Research 2003 – 2006Ljubljana / Slovenia Introduction Three goals of the project: –Interactive visualization of landscape based on very large data sets and photographic material, –development of partitioning algorithms for optimal resource utilization, –implementation on a grid, with an front-end implementation in OpenGL.

5. XLAB Research 2003 – 2006Ljubljana / Slovenia 2401997.48 5066594.99 -1.31 2401992.00 5066586.59 -1.32 2401986.50 5066578.16 -1.33 2401980.88 5066569.52 -1.57 2401980.16 5066568.38 -2.06 2401979.39 5066567.23 -1.66 2401976.94 5066563.48 -1.46 2401964.22 5066544.02 -1.39 2401958.51 5066535.26 -1.51 2401956.88 5066532.75 -1.79 2401950.47 5066522.97 -1.43 2401941.48 5066509.20 -1.37 2401935.75 5066500.42 -1.61 2401933.96 5066497.65 -2.12 2401933.30 5066496.66 -1.65 2401929.95 5066491.55 -1.41 2401923.48 5066481.64 -1.37 2401917.27 5066472.14 -1.42 2401912.46 5066464.77 -1.61 2401910.84 5066462.26 -2.04 2401910.46 5066461.71 -1.74 2401907.44 5066457.12 -1.56 2401910.65 5066462.63 -2.20 2401911.97 5066464.70 -1.62 2401913.97 5066467.78 -1.40 2401997.48 5066594.99 -1.31 2401992.00 5066586.59 -1.32 2401986.50 5066578.16 -1.33 2401980.88 5066569.52 -1.57 2401980.16 5066568.38 -2.06 2401979.39 5066567.23 -1.66 2401976.94 5066563.48 -1.46 2401964.22 5066544.02 -1.39 2401958.51 5066535.26 -1.51 2401956.88 5066532.75 -1.79 2401950.47 5066522.97 -1.43 2401941.48 5066509.20 -1.37 2401935.75 5066500.42 -1.61 2401933.96 5066497.65 -2.12 2401933.30 5066496.66 -1.65 2401929.95 5066491.55 -1.41 2401923.48 5066481.64 -1.37 2401917.27 5066472.14 -1.42 2401912.46 5066464.77 -1.61 2401910.84 5066462.26 -2.04 2401910.46 5066461.71 -1.74 2401907.44 5066457.12 -1.56 2401910.65 5066462.63 -2.20 2401911.97 5066464.70 -1.62 2401913.97 5066467.78 -1.40 Available datasets Based on GIS –data does not provide high enough resolution Based on LiDAR (laser scan) –high volume –mesh resolution: ~ 10cm x 10cm –high memory and cpu requirements Obtained from a simulation –high volume –highly dynamic

6. XLAB Research 2003 – 2006Ljubljana / Slovenia Demo Demonstration of the LiDAR dataset visualization Live demo

7. XLAB Research 2003 – 2006Ljubljana / Slovenia full mesh (half-edges) subset of points Visualisation Delaunay triangulation using Fortune’s sweepline alg. O(N log N) full LiDAR data (bag of points) selection current view mesh simplification using edge decimation O(N log N) simplified mesh (half-edges) parallelizable

8. XLAB Research 2003 – 2006Ljubljana / Slovenia Socha- Executer simplified mesh Socha- Executer Socha- Executer Visualisation (cont.) full LiDAR data (bag of points) selection distribution of computation current view OpenGL rendering

9. XLAB Research 2003 – 2006Ljubljana / Slovenia Visualisation distribution Data (mesh) depends on the selected view, and cannot be pre-computed Considerable workload and memory requirements can be distributed to Grid nodes Process can be pipelined Depending on algorithm for combining (stitching) the sub-meshes, inter-node communication may be required. Front-end Partitioning agent Socha-Executer

10. XLAB Research 2003 – 2006Ljubljana / Slovenia Domain decomposition Trivial (i.e. slicing) Uneven load, varies greatly with the selected view, not tunable for different CPU speeds, network bandwidths etc. Proposal 1: checkerboard Even load, independent of view, requires fine decomposition, fine-grained internode communication during stitching, statically tunable.

11. XLAB Research 2003 – 2006Ljubljana / Slovenia Domain decomposition (cont.) Proposal 2: view-based Every node stores all points, dynamic scheduling, even load, independent of view, decomposition can be coarser, tunable in real-time.

12. XLAB Research 2003 – 2006Ljubljana / Slovenia Planned results Planned test Load distribution test based on pre-recorded fly paths Comparison of the proposed decompositions Nodes used: -cluster-like, -heterogeneous, higher network latency.

13. XLAB Research 2003 – 2006Ljubljana / Slovenia Conclusions & Future work High-performance Grid visualization engine Mesh construction and simplification is distributed, two domain decompositions proposed, both allow even and tunable node load. Further development Grid engine: –automatic adaptation to node speed and load, –further optimization of decomposition and communication. Visualization: –textures, –meshless surface construction.

14. XLAB Research 2003 – 2006Ljubljana / Slovenia Contact XLAB d.o.o. Teslova 30 SI-1000 Ljubljana Tel: 01 477 6777 http://www.xlab.si http://research.xlab.si marjan.sterk@xlab.si