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101
Voronoi diagrams  a survey of a fundamental geometric data structure
 ACM COMPUTING SURVEYS
, 1991
"... This paper presents a survey of the Voronoi diagram, one of the most fundamental data structures in computational geometry. It demonstrates the importance and usefulness of the Voronoi diagram in a wide variety of fields inside and outside computer science and surveys the history of its development. ..."
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Cited by 560 (5 self)
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This paper presents a survey of the Voronoi diagram, one of the most fundamental data structures in computational geometry. It demonstrates the importance and usefulness of the Voronoi diagram in a wide variety of fields inside and outside computer science and surveys the history of its development. The paper puts particular emphasis on the unified exposition of its mathematical and algorithmic properties. Finally, the paper provides the first comprehensive bibliography on Voronoi diagrams and related structures.
Closest Point Search in Lattices
 IEEE TRANS. INFORM. THEORY
, 2000
"... In this semitutorial paper, a comprehensive survey of closestpoint search methods for lattices without a regular structure is presented. The existing search strategies are described in a unified framework, and differences between them are elucidated. An efficient closestpoint search algorithm, ba ..."
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Cited by 194 (1 self)
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In this semitutorial paper, a comprehensive survey of closestpoint search methods for lattices without a regular structure is presented. The existing search strategies are described in a unified framework, and differences between them are elucidated. An efficient closestpoint search algorithm, based on the SchnorrEuchner variation of the Pohst method, is implemented. Given an arbitrary point x 2 R m and a generator matrix for a lattice , the algorithm computes the point of that is closest to x. The algorithm is shown to be substantially faster than other known methods, by means of a theoretical comparison with the Kannan algorithm and an experimental comparison with the Pohst algorithm and its variants, such as the recent ViterboBoutros decoder. The improvement increases with the dimension of the lattice. Modifications of the algorithm are developed to solve a number of related search problems for lattices, such as finding a shortest vector, determining the kissing number, compu...
Counting Solutions to Linear and Nonlinear Constraints through Ehrhart Polynomials: Applications to Analyze and Transform Scientific Programs
, 1996
"... In order to produce efficient parallel programs, optimizing compilers need to include an analysis of the initial sequential code. When analyzing loops with affine loop bounds, many computations are relevant to the same general problem: counting the number of integer solutions of selected free variab ..."
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Cited by 96 (0 self)
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In order to produce efficient parallel programs, optimizing compilers need to include an analysis of the initial sequential code. When analyzing loops with affine loop bounds, many computations are relevant to the same general problem: counting the number of integer solutions of selected free variables in a set of linear and/or nonlinear parameterized constraints. For example, computing the number of flops executed by a loop, of memory locations touched by a loop, of cache lines touched by a loop, or of array elements that need to be transmitted from a processor to another during the execution of a loop, is useful to determine if a loop is load balanced, evaluate message traffic and allocate message buffers. The objective of the presented method is to evaluate symbolically, in terms of symbolic constants (the size parameters) , this number of integer solutions. By modeling the considered counting problem as a union of rational convex polytopes, the number of included integer points is ...
The Two Faces of Lattices in Cryptology
, 2001
"... Lattices are regular arrangements of points in ndimensional space, whose study appeared in the 19th century in both number theory and crystallography. Since the appearance of the celebrated LenstraLenstra Lov'asz lattice basis reduction algorithm twenty years ago, lattices have had surprising ..."
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Cited by 69 (16 self)
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Lattices are regular arrangements of points in ndimensional space, whose study appeared in the 19th century in both number theory and crystallography. Since the appearance of the celebrated LenstraLenstra Lov'asz lattice basis reduction algorithm twenty years ago, lattices have had surprising applications in cryptology. Until recently, the applications of lattices to cryptology were only negative, as lattices were used to break various cryptographic schemes. Paradoxically, several positive cryptographic applications of lattices have emerged in the past five years: there now exist publickey cryptosystems based on the hardness of lattice problems, and lattices play a crucial role in a few security proofs.
Parametric Analysis of Polyhedral Iteration Spaces
 JOURNAL OF VLSI SIGNAL PROCESSING
, 1998
"... In the area of automatic parallelization of programs, analyzing and transforming loop nests with parametric affine loop bounds requires fundamental mathematical results. The most common geometrical model of iteration spaces, called the polytope model, is based on mathematics dealing with convex and ..."
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Cited by 68 (13 self)
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In the area of automatic parallelization of programs, analyzing and transforming loop nests with parametric affine loop bounds requires fundamental mathematical results. The most common geometrical model of iteration spaces, called the polytope model, is based on mathematics dealing with convex and discrete geometry, linear programming, combinatorics and geometry of numbers. In this paper, we present automatic methods for computing the parametric vertices and the Ehrhart polynomial, i.e. a parametric expression of the number of integer points, of a polytope defined by a set of parametric linear constraints. These methods have many applications in analysis and transformations of nested loop programs. The paper is illustrated with exact symbolic array dataflow analysis, estimation of execution time, and with the computation of the maximum available parallelism of given loop nests.
An Improved WorstCase to AverageCase Connection for Lattice Problems (extended abstract)
 In FOCS
, 1997
"... We improve a connection of the worstcase complexity and the averagecase complexity of some wellknown lattice problems. This fascinating connection was first discovered by Ajtai [1] in 1996. We improve the exponent of this connection from 8 to 3:5 + ffl. Department of Computer Science, State Unive ..."
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Cited by 54 (10 self)
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We improve a connection of the worstcase complexity and the averagecase complexity of some wellknown lattice problems. This fascinating connection was first discovered by Ajtai [1] in 1996. We improve the exponent of this connection from 8 to 3:5 + ffl. Department of Computer Science, State University of New York at Buffalo, Buffalo, NY 14260. Research supported in part by NSF grants CCR9319393 and CCR9634665, and an Alfred P. Sloan Fellowship. Email: cai@cs.buffalo.edu y Department of Computer Science, State University of New York at Buffalo, Buffalo, NY 14260. Research supported in part by NSF grants CCR9319393 and CCR9634665. Email: apn@cs.buffalo.edu 1 Introduction A lattice L is a discrete additive subgroup of R n . There are many fascinating problems concerning lattices, both from a structural and from an algorithmic point of view [12, 20, 11, 13]. The study of lattice problems can be traced back to Gauss, Dirichlet and Hermite, among others [8, 6, 14]. The subje...
Averaging bounds for lattices and linear codes
 IEEE Trans. Information Theory
, 1997
"... Abstract — General random coding theorems for lattices are derived from the Minkowski–Hlawka theorem and their close relation to standard averaging arguments for linear codes over finite fields is pointed out. A new version of the Minkowski–Hlawka theorem itself is obtained as the limit, for p!1,ofa ..."
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Cited by 50 (1 self)
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Abstract — General random coding theorems for lattices are derived from the Minkowski–Hlawka theorem and their close relation to standard averaging arguments for linear codes over finite fields is pointed out. A new version of the Minkowski–Hlawka theorem itself is obtained as the limit, for p!1,ofasimple lemma for linear codes over GF (p) used with plevel amplitude modulation. The relation between the combinatorial packing of solid bodies and the informationtheoretic “soft packing ” with arbitrarily small, but positive, overlap is illuminated. The “softpacking” results are new. When specialized to the additive white Gaussian noise channel, they reduce to (a version of) the de Buda–Poltyrev result that spherically shaped lattice codes and adecoder that is unaware of the shaping can achieve the rate 1=2 log2 (P=N).
LatticeBased Memory Allocation
, 2003
"... We investigate the problem of memory reuse, for reducing the necessary memory size, in the context of compilation of dedicated processors. Memory reuse is a wellknown concept when allocating registers (i.e., scalar variables). Its (recent) extension to arrays was studied mainly by Lefebvre and Feau ..."
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Cited by 45 (4 self)
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We investigate the problem of memory reuse, for reducing the necessary memory size, in the context of compilation of dedicated processors. Memory reuse is a wellknown concept when allocating registers (i.e., scalar variables). Its (recent) extension to arrays was studied mainly by Lefebvre and Feautrier (for loop parallelization) and by Quillereand Rajopadhye (for circuit synthesis based on recurrence equations) . Both consider a#ne mappings of indices to data, with modulo expressions in the first and (mainly) projections in the second. We develop a mathematical framework based on (integral) critical lattices that subsumes all previous approaches and gives new insights into the problem. Our technique consists first in building an abstract representation of conflicting indices (equivalent in a multidimensional space to the interference graph for register allocation), then in defining an integral lattice, admissible for the set of differences of conflicting indices, used to build a valid modular allocation. We also show the link with critical lattices, successive minima, and basis reduction, and we analyze various strategies for latticebased memory allocation.
Noisy Polynomial Interpolation and Noisy Chinese Remaindering
, 2000
"... Abstract. The noisy polynomial interpolation problem is a new intractability assumption introduced last year in oblivious polynomial evaluation. It also appeared independently in password identification schemes, due to its connection with secret sharing schemes based on Lagrange’s polynomial interpo ..."
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Cited by 41 (2 self)
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Abstract. The noisy polynomial interpolation problem is a new intractability assumption introduced last year in oblivious polynomial evaluation. It also appeared independently in password identification schemes, due to its connection with secret sharing schemes based on Lagrange’s polynomial interpolation. This paper presents new algorithms to solve the noisy polynomial interpolation problem. In particular, we prove a reduction from noisy polynomial interpolation to the lattice shortest vector problem, when the parameters satisfy a certain condition that we make explicit. Standard lattice reduction techniques appear to solve many instances of the problem. It follows that noisy polynomial interpolation is much easier than expected. We therefore suggest simple modifications to several cryptographic schemes recently proposed, in order to change the intractability assumption. We also discuss analogous methods for the related noisy Chinese remaindering problem arising from the wellknown analogy between polynomials and integers. 1
Lattice Reduction in Cryptology: An Update
 Lect. Notes in Comp. Sci
, 2000
"... Lattices are regular arrangements of points in space, whose study appeared in the 19th century in both number theory and crystallography. ..."
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Cited by 36 (7 self)
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Lattices are regular arrangements of points in space, whose study appeared in the 19th century in both number theory and crystallography.