In order to understand how AVS can be adapted to run on the T3D, it is necessary to review the basic structure of AVS. AVS employs a distributed dataflow architecture which allows simulation models to be incorporated into visualization applications. The network paradigm employed by AVS lends itself extremely well to heterogeneous computations where, for example, a simulation model might be executed on a supercomputer while the visualization and control of the model parameters and visualization of the model output is performed either locally or remotely on a workstation.
The AVS structure embodies the principles of modularization, abstraction, and information hiding. The package is composed of modules written in C and FORTRAN, each of which performs a specific function. Using these building blocks, AVS users can interactively construct their own visualization applications by combining modules into executable dataflow networks. The modules in the network may be executed locally on the same machine which is hosting the AVS application, or they may be executed remotely on a different machine.
AVS includes several hundred supported modules organized into module libraries. The system is extensible and users may generate new modules using the Module Generator. The International AVS Center (IAC) maintains an archive of contributed modules which may be downloaded to augment the standard libraries.
We propose to extend the scalability and applicability of AVS by producing an environment for the creation and execution of AVS modules on the CRAY T3D parallel supercomputer. This environment will allow users to create AVS modules for the T3D which can then be incorporated in standard AVS module libraries for general usage. For the user of these libraries, access and use of the T3D is nearly transparent. The appropriate T3D module icon from the module library is simply connected into the AVS dataflow network. If the AVS application is hosted on the T3D frontend, typically a Y-MP, the module will be a local module, otherwise it will execute remotely on the T3D frontend. In either case, the AVS module will provide the user interface and execution control for the T3D code.
This requires the porting of key AVS modules that can fully utilize the computational power of the T3D. For example, volume rendering of large 3D data sets, such as environmental or MRI data can consume hours of CPU time. Using the parallel processing power of the T3D, it is possible to render large volumetric data sets interactively in seconds or less. Such a renderer opens the possibility of creating powerful new learning and diagnosis tools using high performance computing and networking. Other examples are image processing, and iso-surface generation. Many computationally important AVS modules have been identified and will be ported to the T3D and be made available to the public through the IAC.