USC Component of DoD, DoE and NASA Activities:
Graphical User Interfaces and Enabling Technologies.

Visualization tools devised by the University of South Carolina are used for assessment of simulations as well as for improving PICS groundwater code and algorithm development. Primary effort has focused on G3D (an integrated graphical user interface used for post-processing simulations, for preprocessing models and 3D grid generation) and modules which use the Tracking/Steering library to couple to the simulators executing on remote parallel supercomputers:

• Groundwater simulation runs may be post-processed by G3D using various standard features such as multiple slices/dices, time animation, multiple isosurfaces with varying opacity, vectors, mouse control of view, opaque display of material properties, various lighting models, multiple views, and stereo rendering. VCR controls and key-framing are available for movie generation and data archival.

(click here)

• Grid Generation Features of G3D. The 3D grid creation/editing tools have been developed to facilitate the incorporation of topographical features, geological subsurface features, in addition to well data and reference map overlays. Additional integrated features include
• manipulate and refine grids,
• specify heterogeneous model PDE coefficients and parameters (e.g., soil properties such as porosities, permeabilities, hydraulic conductivities, ...) which may be user-customized for general sets of model equations,
• set initial conditions for dependent solution variables (e.g., pressure heads and concentrations) using either 3D patches which may be specified by a constant value or computed using an integrated parser utility,
• specify time-dependent boundary conditions of all types through temporal-spatial linked lists of boundary patches which are also fully edit-able and are rendered in various ways to guarantee data integrity. The user may set the dependent variable values by using G3D's integrated parser utility.

A number of auxillary tools have been produced to facilitate model development by practicing hydrologists, as well as assisting in the development of the GCT series of codes. I/O capabilities are also being incorporated for user readable data as well as binary distributed files for the Paragon. Prototype utilities also have provided access to GIS (Geographic Information System) data bases to import grids from topographical surface measurements. This prototype may be modified to assimilate stream levels and historical contamination records as well as subsurface data for soil properties and contaminant distribution.

• Current G3D Manual
  
• G3D Manual (Postscipt) and companion Figures (1 MByte gzipped Postscipt)

In order to efficiently calibrate models, characterize contaminants and media properties, and optimize remediation schemes, an interactive capability is required. Typically, the modeler needs to observe the effects of current parameter settings, and based on those observations, they must then be permitted to alter the parameters in a non-intrusively manner during the simulation. This methodology may also be used to test and fine tune numerical algorithms for accuracy, robustness, and efficiency without affecting load balancing.

The South Carolina component has developed a tracking and steering library to connect parallel machines and workstations to enable this functionality. In this library the remote MPP machine is set as host with a graphics node that handles requests from client workstations in such a manner so as not to disturb the load-balance of the compute nodes (unless the applications programmer so wishes). This node also uses the compression modules (see below) and the XDR libraries with remote procedure calls to transfer the data to the client workstation for processing and interactive analysis.

On-line Steering Library Manual.

Current bandwidths preclude the interactive simulation of large scale models on remote supercomputers if even moderately sized data sets are to be transfered for analysis or steering. The wavelet analysis research group at the University of South Carolina have developed higher dimensional multiresolution-based data compression and processing libraries to enable efficient and effective assessment of interactive simulations on massively parallel platforms.

The following image (on the left) provides a comparison of the reconstructed images from compressed files with high levels of compression for the original simulated pressure field. The image on the right utilizes the enhanced compression encoders applied to a contaminant transport data set with stronger gradients.

The figure on the right consists of images all rendered using identical orthogonal slices and an isosurface of .3 of maximum concentration percentage.

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