Abstract In the coming era of exascale supercomputing, in-situ visualization will be a crucial approach for reducing the output data size. A problem of in-situ visualization is that it loses interactivity if a steering method is not adopted. In this paper, we propose a new method for the interactive analysis of in-situ visualization images produced by a batch simulation job. A key idea is to apply numerous (thousands to millions) in-situ visualizations simultaneously. The viewer then analyzes the image database interactively during postprocessing. If each movie can be compressed to 100 MB, one million movies will only require 100 TB, which is smaller than the size of the raw numerical data in exascale supercomputing. We performed a feasibility study using the proposed method. Multiple movie files were produced by a simulation and they were analyzed using a specially designed movie player. The user could change the viewing angle, the visualization method, and the parameters interactively by retrieving an appropriate sequence of images from the movie dataset.
developed a steering simulation and visualization framework for environmental science where dynamical control over the Internet was implemented @cite_11 . Their user interface was constructed on web browsers. developed an in-situ visualization system on the Colombia supercomputer for running a weather forecasting model @cite_13 . (Our experimental system described in section is similar to their system because multiple MPEG files are generated by multiple in-situ visualizations. However, their movies are shown separately in each panel of a tiled display system, whereas ours are used as a database.) developed an in-situ visualization system where the parallel visualization processing can run on a different computer system from the simulation computer system @cite_4 . In their development, special emphasis was placed on producing a steering environment with existing simulation codes.
@cite_13 @cite_4 @cite_11
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We describe a concurrent visualization pipeline designed for operation in a production supercomputing environment. The facility was initially developed on the NASA Ames "Columbia" supercomputer for a massively parallel forecast model (GEOS4). During the 2005 Atlantic hurricane season, GEOS4 was run 4 times a day under tight time constraints so that its output could be included in an ensemble prediction that was made available to forecasters at the National Hurricane Center. Given this time-critical context, we designed a configurable concurrent pipeline to visualize multiple global fields without significantly affecting the runtime model performance or reliability. We use MPEG compression of the accruing images to facilitate live low-bandwidth distribution of multiple visualization streams to remote sites. We also describe the use of our concurrent visualization framework with a global ocean circulation model, which provides a 864-fold increase in the temporal resolution of practically achievable animations. In both the atmospheric and oceanic circulation models, the application scientists gained new insights into their model dynamics, due to the high temporal resolution animations attainable In the context of scientific computing, the computational steering consists in the coupling of numerical simulations with 3D visualization systems through the network. This allows scientists to monitor online the intermediate results of their computations in a more interactive way than the batch mode, and allows them to modify the simulation parameters on-the-fly. While most of existing computational steering environments support parallel simulations, they are often limited to sequential visualization systems. This may lead to an important bottleneck and increased rendering time. To achieve the required performance for online visualization, we have designed the EPSN framework, a computational steering environment that enables to interconnect legacy parallel simulations with parallel visualization systems. For this, we have introduced a redistribution algorithm for unstructured data, that is well adapted to the context of M times N computational steering. Then, we focus on the design of our parallel viewer and present some experimental results obtained with a particle-based simulation in astrophysics This paper introduces a novel visualization approach that can effectively facilitate the analysis, control, and refinement of dynamic environmental simulations on the World Wide Web. This approach overcomes drawbacks of current Internet Geographic Information System (GIS) technologies by providing an effective and efficient mechanism for two-way and sustained communication and synchronization between the visualization and the modeling processes. The critical aspect of this approach is the establishment of a virtual environment on the Internet using the applet-servlet-socket architecture that supports real-time interactive and collaborative visualization of an environmental modeling process. In this virtual environment, the model residing in the simulation application server is fed with real-time rainfall data from a remote data server through a socket connection. The computational modeling and visualization can take place simultaneously on the application server and the client sides. As modeling computations proceed on the server, modeling results and outputs stream into the client side continuously. The client interface is updated with live 3D displays (not in the sense of predefined 3D animations provided by AVI or dynamic GIF files). Meanwhile, these 3D graphics can act as a support for further user interactions. A hydrological model, TOPMODEL, is implemented using the proposed web-based visualization environment to demonstrate the applicability of the proposed approach in facilitating environmental modeling and simulation.