Results 1  10
of
166
A rapid hierarchical radiosity algorithm
 Computer Graphics
, 1991
"... This paper presents a rapid hierarchical radiosity algorithm for illuminating scenes containing lar e polygonal patches. The afgorithm constructs a hierarchic“J representation of the form factor matrix by adaptively subdividing patches into su bpatches according to a usersupplied error bound. The a ..."
Abstract

Cited by 409 (11 self)
 Add to MetaCart
(Show Context)
This paper presents a rapid hierarchical radiosity algorithm for illuminating scenes containing lar e polygonal patches. The afgorithm constructs a hierarchic“J representation of the form factor matrix by adaptively subdividing patches into su bpatches according to a usersupplied error bound. The algorithm guarantees that all form factors are calculated to the same precision, removing many common image artifacts due to inaccurate form factors. More importantly, the al orithm decomposes the form factor matrix into at most O? n) blocks (where n is the number of elements). Previous radiosity algorithms represented the elementtoelement transport interactions with n2 form factors. Visibility algorithms are given that work well with this approach. Standard techniques for shooting and gathering can be used with the hierarchical representation to solve for equilibrium radiosities, but we also discuss using a brightnessweighted error criteria, in conjunction with multigrldding, to even more rapidly progressively refine the image.
A Decomposition of MultiDimensional Point Sets with Applications to kNearestNeighbors and nBody Potential Fields
 J. ACM
, 1992
"... We define the notion of a wellseparated pair decomposition of points in ddimensional space. We then develop efficient sequential and parallel algorithms for computing such a decomposition. We apply the resulting decomposition to the efficient computation of knearest neighbors and nbody potential ..."
Abstract

Cited by 267 (4 self)
 Add to MetaCart
We define the notion of a wellseparated pair decomposition of points in ddimensional space. We then develop efficient sequential and parallel algorithms for computing such a decomposition. We apply the resulting decomposition to the efficient computation of knearest neighbors and nbody potential fields.
A Parallel Hashed OctTree NBody Algorithm
, 1993
"... We report on an efficient adaptive Nbody method which we have recently designed and implemented. The algorithm computes the forces on an arbitrary distribution of bodies in a time which scales as N log N with the particle number. The accuracy of the force calculations is analytically bounded, and c ..."
Abstract

Cited by 199 (14 self)
 Add to MetaCart
We report on an efficient adaptive Nbody method which we have recently designed and implemented. The algorithm computes the forces on an arbitrary distribution of bodies in a time which scales as N log N with the particle number. The accuracy of the force calculations is analytically bounded, and can be adjusted via a user defined parameter between a few percent relative accuracy, down to machine arithmetic accuracy. Instead of using pointers to indicate the topology of the tree, we identify each possible cell with a key. The mapping of keys into memory locations is achieved via a hash table. This allows the program to access data in an efficient manner across multiple processors. Performance of the parallel program is measured on the 512 processor Intel Touchstone Delta system. We also comment on a number of wideranging applications which can benefit from application of this type of algorithm.
Iterative Solution of Linear Systems
 Acta Numerica
, 1992
"... this paper is as follows. In Section 2, we present some background material on general Krylov subspace methods, of which CGtype algorithms are a special case. We recall the outstanding properties of CG and discuss the issue of optimal extensions of CG to nonHermitian matrices. We also review GMRES ..."
Abstract

Cited by 130 (8 self)
 Add to MetaCart
this paper is as follows. In Section 2, we present some background material on general Krylov subspace methods, of which CGtype algorithms are a special case. We recall the outstanding properties of CG and discuss the issue of optimal extensions of CG to nonHermitian matrices. We also review GMRES and related methods, as well as CGlike algorithms for the special case of Hermitian indefinite linear systems. Finally, we briefly discuss the basic idea of preconditioning. In Section 3, we turn to Lanczosbased iterative methods for general nonHermitian linear systems. First, we consider the nonsymmetric Lanczos process, with particular emphasis on the possible breakdowns and potential instabilities in the classical algorithm. Then we describe recent advances in understanding these problems and overcoming them by using lookahead techniques. Moreover, we describe the quasiminimal residual algorithm (QMR) proposed by Freund and Nachtigal (1990), which uses the lookahead Lanczos process to obtain quasioptimal approximate solutions. Next, a survey of transposefree Lanczosbased methods is given. We conclude this section with comments on other related work and some historical remarks. In Section 4, we elaborate on CGNR and CGNE and we point out situations where these approaches are optimal. The general class of Krylov subspace methods also contains parameterdependent algorithms that, unlike CGtype schemes, require explicit information on the spectrum of the coefficient matrix. In Section 5, we discuss recent insights in obtaining appropriate spectral information for parameterdependent Krylov subspace methods. After that, 4 R.W. Freund, G.H. Golub and N.M. Nachtigal
A Rapid Hierarchical Rendering Technique for Translucent Materials
 ACM Transactions on Graphics
, 2002
"... This paper introduces an efficient twopass rendering technique for translucent materials. We decouple the computation of irradiance at the surface from the evaluation of scattering inside the material. This is done by splitting the evaluation into two passes, where the first pass consists of comput ..."
Abstract

Cited by 109 (4 self)
 Add to MetaCart
This paper introduces an efficient twopass rendering technique for translucent materials. We decouple the computation of irradiance at the surface from the evaluation of scattering inside the material. This is done by splitting the evaluation into two passes, where the first pass consists of computing the irradiance at selected points on the surface. The second pass uses a rapid hierarchical integration technique to evaluate a diffusion approximation based on the irradiance samples. This approach is substantially faster than previous methods for rendering translucent materials, and it has the advantage that it integrates seamlessly with both scanline rendering and global illumination methods. We show several images and animations from our implementation that demonstrate that the approach is both fast and robust, making it suitable for rendering translucent materials in production.
Astrophysical Nbody Simulations Using Hierarchical Tree Data Structures
, 1992
"... We report on recent large astrophysical Nbody simulations executed on the Intel Touchstone Delta system. We review the astrophysical motivation, and the numerical techniques, and discuss steps taken to parallelize these simulations. The methods scale as O(N log N), for large values of N , and also ..."
Abstract

Cited by 107 (14 self)
 Add to MetaCart
(Show Context)
We report on recent large astrophysical Nbody simulations executed on the Intel Touchstone Delta system. We review the astrophysical motivation, and the numerical techniques, and discuss steps taken to parallelize these simulations. The methods scale as O(N log N), for large values of N , and also scale linearly with the number of processors. The performance, sustained for a duration of 67 hours was between 5.1 and 5.4 Gflop/sec on a 512 processor system.
BSPlib: The BSP Programming Library
, 1998
"... BSPlib is a small communications library for bulk synchronous parallel (BSP) programming which consists of only 20 basic operations. This paper presents the full definition of BSPlib in C, motivates the design of its basic operations, and gives examples of their use. The library enables programming ..."
Abstract

Cited by 98 (8 self)
 Add to MetaCart
BSPlib is a small communications library for bulk synchronous parallel (BSP) programming which consists of only 20 basic operations. This paper presents the full definition of BSPlib in C, motivates the design of its basic operations, and gives examples of their use. The library enables programming in two distinct styles: direct remote memory access using put or get operations, and bulk synchronous message passing. Currently, implementations of BSPlib exist for a variety of modern architectures, including massively parallel computers with distributed memory, shared memory multiprocessors, and networks of workstations. BSPlib has been used in several scientific and industrial applications; this paper briefly describes applications in benchmarking, Fast Fourier Transforms, sorting, and molecular dynamics.
Abstractions for Recursive Pointer Data Structures: Improving the Analysis and Transformation of Imperative Programs
, 1992
"... Even though impressive progress has been made... ..."
A General Data Dependence Test for Dynamic, PointerBased Data Structures
 In Proc. ACM PLDI
, 1994
"... Optimizing compilers require accurate dependence testing to enable numerous, performanceenhancing transformations. However, data dependence testing is a difficult problem, particularly in the presence of pointers. Though existing approaches work well for pointers to named memory locations (i.e. oth ..."
Abstract

Cited by 71 (2 self)
 Add to MetaCart
Optimizing compilers require accurate dependence testing to enable numerous, performanceenhancing transformations. However, data dependence testing is a difficult problem, particularly in the presence of pointers. Though existing approaches work well for pointers to named memory locations (i.e. other variables) , they are overly conservative in the case of pointers to unnamed memory locations. The latter occurs in the context of dynamic, pointerbased data structures, used in a variety of applications ranging from system software to computational geometry to Nbody and circuit simulations. In this paper we present a new technique for performing more accurate data dependence testing in the presence of dynamic, pointerbased data structures. We will demonstrate its effectiveness by breaking false dependences that existing approaches cannot, and provide results which show that removing these dependences enables significant parallelization of a real application. 1 Introduction and Motiv...
Clustering for Glossy Global Illumination
 ACM TRANSACTIONS ON GRAPHICS
, 1997
"... We present a new clustering algorithm for global illumination in complex environments. The new algorithm extends previous work on clustering for radiosity to allow for nondiffuse (glossy) reflectors. We represent clusters as points with directional distributions of outgoing and incoming radiance and ..."
Abstract

Cited by 65 (4 self)
 Add to MetaCart
We present a new clustering algorithm for global illumination in complex environments. The new algorithm extends previous work on clustering for radiosity to allow for nondiffuse (glossy) reflectors. We represent clusters as points with directional distributions of outgoing and incoming radiance and importance, and we derive an error bound for transfers between these clusters. The algorithm groups input surfaces into a hierarchy of clusters, and then permits clusters to interact only if the error bound is below an acceptable tolerance. We show that the algorithm is asymptotically more efficient than previous clustering algorithms even when restricted to ideally diffuse environments. Finally, we demonstrate the performance of our method on two complex glossy environments.