Towards Efficient Parallel Radiosity for DSM-based Parallel Computers Using Virtual Interfaces

This paper presents the performance evaluation of a new technique for radiosity computation which aims at exploiting efficiently the different levels of a memory hierarchy of both sequential and parallel computers. Such ability is essential when dealing with complex environments having several millions of polygons. The principle of our technique is to split the initial environment into several sub-environments and compute the radiosity within each sub-environment. Exchange of energy between sub-environments is performed by means of virtual interfaces and visibility masks. The size of sub-environments can be adapted in order to fit into a cache or a local memory. We performed several experiments using an SGI Origin 2000 to show the effectiveness of our solution. It improves both the sequential and parallel execution of a progressive radiosity algorithm. Our technique decreases the execution time on one processor of an SGI Origin 2000 by a factor of more than 5 and leads to a very good efficiency for complex environments (1 million of polygons) on a multiprocessor configuration

Immersive Insights: A Hybrid Analytics System for Collaborative Exploratory Data Analysis

In the past few years, augmented reality (AR) and virtual reality (VR) technologies have experienced terrific improvements in both accessibility and hardware capabilities, encouraging the application of these devices across various domains. While researchers have demonstrated the possible advantages of AR and VR for certain data science tasks, it is still unclear how these technologies would perform in the context of exploratory data analysis (EDA) at large. In particular, we believe it is important to better understand which level of immersion EDA would concretely benefit from, and to quantify the contribution of AR and VR with respect to standard analysis workflows. In this work, we leverage a Dataspace reconfigurable hybrid reality environment to study how data scientists might perform EDA in a co-located, collaborative context. Specifically, we propose the design and implementation of Immersive Insights, a hybrid analytics system combining high-resolution displays, table projections, and augmented reality (AR) visualizations of the data. We conducted a two-part user study with twelve data scientists, in which we evaluated how different levels of data immersion affect the EDA process and compared the performance of Immersive Insights with a state-of-the-art, non-immersive data analysis system.Comment: VRST 201

Convergence Analysis for a Parallel Radiosity Algorithm using Virtual Interfaces

Radiosity algorithms generate a large amount of computations. To reduce it, several methods have been proposed, relying either on a sequential or on a parallel approach. Some of them attempt to improve data locality. Most of the methods subdivide the scene into several sub-environments for which radiosity computation is performed independently. In this paper, we present a method to compute solutions, of a desired accuracy, for radiosity algorithms operating on sub-environments. We have applied this technique to the "virtual interface" method, while keeping the data locality. It requires only minor modifications. We have experimented our method with a distributed shared memory multiprocessors (SGI Origin 2000 ). We obtain promising speed-ups, with a small error, for a given convergence threshold. 1 Introduction Over the past decade, radiosity has become more and more popular since it is capable of producing realistic images, computing the indirect diffuse component. Computing a radiosi..

SVMview: a Performance Tuning Tool for DSM-based Parallel Computers

This paper describes a performance tuning tool, named SVMview, for DSM-based parallel computers. SVMview is a tool for doing a post-mortem analysis of page movements generated during the execution of Fortran-S programs. This tool is able to analyze some particular phenomena such as false-sharing which occurs when several processors write to the same page simultaneously. Such behavior entails badly the performance of DSM systems, and thus are particularly important to be detected

Multi-modal, Interactive, Visualization of Robot Soccer

Multi-modal visualization, as a tool for collaborative exploration of complex datasets or simulations, is rapidly becoming important. In this paper we discuss a case study in collaborative visualization on Robot soccer. Our visualization work covers the three major platform types: Cave, workbench and workstation. We chart what the relation is between platform and visualization and show what the added value of the collaborative approach is. keywords : simulation, collaborative visualization, cave, workbench, DAS 1 Introduction The rapid development in display technology and computer graphics has led to a diversification of the traditional visualization platform, the graphical workstation, into three categories. Loosely speaking one can identify these categories as (i) immersive, e.g. the Cave [4], (ii) partially immersive, e.g. the workbench [8], and (iii) the traditional workstation. A comprehensive survey of important trends and directions is given in [7, 6, 1]. This diversific..

Visibility Masks for Solving Complex Radiosity Computations on Multiprocessors

This paper presents a strategy to handle very complex scenes for radiosity computation. Compared to other radiosity algorithms, our solution focuses on the ability to compute the radiosity in local environments instead of solving the problem for the whole environment. By splitting the problem into subproblems, using Virtual Interface and Visibility Masks

Performance Analysis of a 3D Parallel Volume Rendering Application on Scalable Tiled Displays

Abstract Current high-speed general-purpose networks, suc