Results 1  10
of
89
A New Efficient Algorithm for Computing Gröbner Bases (F4)
 IN: ISSAC ’02: PROCEEDINGS OF THE 2002 INTERNATIONAL SYMPOSIUM ON SYMBOLIC AND ALGEBRAIC COMPUTATION
, 2002
"... This paper introduces a new efficient algorithm for computing Gröbner bases. To avoid as much as possible intermediate computation, the algorithm computes successive truncated Gröbner bases and it replaces the classical polynomial reduction found in the Buchberger algorithm by the simultaneous reduc ..."
Abstract

Cited by 372 (56 self)
 Add to MetaCart
This paper introduces a new efficient algorithm for computing Gröbner bases. To avoid as much as possible intermediate computation, the algorithm computes successive truncated Gröbner bases and it replaces the classical polynomial reduction found in the Buchberger algorithm by the simultaneous reduction of several polynomials. This powerful reduction mechanism is achieved by means of a symbolic precomputation and by extensive use of sparse linear algebra methods. Current techniques in linear algebra used in Computer Algebra are reviewed together with other methods coming from the numerical field. Some previously untractable problems (Cyclic 9) are presented as well as an empirical comparison of a first implementation of this algorithm with other well known programs. This comparison pays careful attention to methodology issues. All the benchmarks and CPU times used in this paper are frequently updated and available on a Web page. Even though the new algorithm does not improve the worst case complexity it is several times faster than previous implementations both for integers and modulo computations.
On Fast and Provably Secure Message Authentication Based on Universal Hashing
 In Advances in Cryptology – CRYPTO ’96
, 1996
"... There are wellknown techniques for message authentication using universal hash functions. This approach seems very promising, as it provides schemes that are both efficient and provably secure under reasonable assumptions. This paper contributes to this line of research in two ways. First, it analy ..."
Abstract

Cited by 90 (0 self)
 Add to MetaCart
(Show Context)
There are wellknown techniques for message authentication using universal hash functions. This approach seems very promising, as it provides schemes that are both efficient and provably secure under reasonable assumptions. This paper contributes to this line of research in two ways. First, it analyzes the basic construction and some variants under more realistic and practical assumptions. Second, it shows how these schemes can be efficiently implemented, and it reports on the results of empirical performance tests that demonstrate that these schemes are competitive with other commonly employed schemes whose security is less wellestablished. 1 Introduction Message Authentication. Message authentication schemes are an important security tool. As more and more data is being transmitted over networks, the need for secure, highspeed, softwarebased message authentication is becoming more acute. The setting for message authentication is the following. Two parties A and B agree on a secre...
Discrete logarithms in gf(p) using the number field sieve
 SIAM J. Discrete Math
, 1993
"... Recently, several algorithms using number field sieves have been given to factor a number n in heuristic expected time Ln[1/3; c], where Ln[v; c] = exp{(c + o(1))(log n) v (log log n) 1−v}, for n → ∞. In this paper we present an algorithm to solve the discrete logarithm problem for GF (p) with heur ..."
Abstract

Cited by 88 (1 self)
 Add to MetaCart
(Show Context)
Recently, several algorithms using number field sieves have been given to factor a number n in heuristic expected time Ln[1/3; c], where Ln[v; c] = exp{(c + o(1))(log n) v (log log n) 1−v}, for n → ∞. In this paper we present an algorithm to solve the discrete logarithm problem for GF (p) with heuristic expected running time Lp[1/3; 3 2/3]. For numbers of a special form, there is an asymptotically slower but more practical version of the algorithm.
On The Complexity Of Computing Determinants
 COMPUTATIONAL COMPLEXITY
, 2001
"... We present new baby steps/giant steps algorithms of asymptotically fast running time for dense matrix problems. Our algorithms compute the determinant, characteristic polynomial, Frobenius normal form and Smith normal form of a dense n n matrix A with integer entries in (n and (n bi ..."
Abstract

Cited by 63 (21 self)
 Add to MetaCart
We present new baby steps/giant steps algorithms of asymptotically fast running time for dense matrix problems. Our algorithms compute the determinant, characteristic polynomial, Frobenius normal form and Smith normal form of a dense n n matrix A with integer entries in (n and (n bit operations; here denotes the largest entry in absolute value and the exponent adjustment by "+o(1)" captures additional factors for positive real constants C 1 , C 2 , C 3 . The bit complexity (n results from using the classical cubic matrix multiplication algorithm. Our algorithms are randomized, and we can certify that the output is the determinant of A in a Las Vegas fashion. The second category of problems deals with the setting where the matrix A has elements from an abstract commutative ring, that is, when no divisions in the domain of entries are possible. We present algorithms that deterministically compute the determinant, characteristic polynomial and adjoint of A with n and O(n ) ring additions, subtractions and multiplications.
Factoring Multivariate Polynomials via Partial Differential Equations
 Math. Comput
, 2000
"... A new method is presented for factorization of bivariate polynomials over any field of characteristic zero or of relatively large characteristic. It is based on a simple partial differential equation that gives a system of linear equations. Like Berlekamp's and Niederreiter's algorithms fo ..."
Abstract

Cited by 60 (9 self)
 Add to MetaCart
A new method is presented for factorization of bivariate polynomials over any field of characteristic zero or of relatively large characteristic. It is based on a simple partial differential equation that gives a system of linear equations. Like Berlekamp's and Niederreiter's algorithms for factoring univariate polynomials, the dimension of the solution space of the linear system is equal to the number of absolutely irreducible factors of the polynomial to be factored and any basis for the solution space gives a complete factorization by computing gcd's and by factoring univariate polynomials over the ground field. The new method finds absolute and rational factorizations simultaneously and is easy to implement for finite fields, local fields, number fields, and the complex number field. The theory of the new method allows an effective Hilbert irreducibility theorem, thus an efficient reduction of polynomials from multivariate to bivariate.
On efficient sparse integer matrix Smith normal form computations
, 2001
"... We present a new algorithm to compute the Integer Smith normal form of large sparse matrices. We reduce the computation of the Smith form to independent, and therefore parallel, computations modulo powers of wordsize primes. Consequently, the algorithm does not suffer from coefficient growth. W ..."
Abstract

Cited by 44 (20 self)
 Add to MetaCart
We present a new algorithm to compute the Integer Smith normal form of large sparse matrices. We reduce the computation of the Smith form to independent, and therefore parallel, computations modulo powers of wordsize primes. Consequently, the algorithm does not suffer from coefficient growth. We have implemented several variants of this algorithm (Elimination and/or BlackBox techniques) since practical performance depends strongly on the memory available. Our method has proven useful in algebraic topology for the computation of the homology of some large simplicial complexes.
Linbox: A Generic Library For Exact Linear Algebra
, 2002
"... Base Class pointers Concrete Field virtual functions Field Archetype Linbox field archetype Figure 1: Black box design. The LinBox black box matrix archetype is simpler than the field archetype because the design constraints are less stringent. As with the field type, we need a common object ..."
Abstract

Cited by 40 (13 self)
 Add to MetaCart
Base Class pointers Concrete Field virtual functions Field Archetype Linbox field archetype Figure 1: Black box design. The LinBox black box matrix archetype is simpler than the field archetype because the design constraints are less stringent. As with the field type, we need a common object interface to describe how algorithms are to access black box matrices, but it only requires functions to access the matrix's dimensions and to apply the matrix or its transpose to a vector. Thus our black box matrix archetype is simply an abstract class, and all actual black box matrices are subclasses of the archetype class. We note that the overhead involved with this inheritance mechanism is negligible in comparison with the execution time of the methods, unlike for our field element types.
Efficient Matrix Preconditioners for Black Box Linear Algebra
 LINEAR ALGEBRA AND APPLICATIONS 343–344 (2002), 119–146. SPECIAL ISSUE ON STRUCTURED AND INFINITE SYSTEMS OF LINEAR EQUATIONS
, 2001
"... The main idea of the "black box" approach in exact linear algebra is to reduce matrix problems to the computation of minimum polynomials. In most cases preconditioning is necessary to obtain the desired result. Here, good preconditioners will be used to ensure geometrical / algebraic prope ..."
Abstract

Cited by 36 (23 self)
 Add to MetaCart
(Show Context)
The main idea of the "black box" approach in exact linear algebra is to reduce matrix problems to the computation of minimum polynomials. In most cases preconditioning is necessary to obtain the desired result. Here, good preconditioners will be used to ensure geometrical / algebraic properties on matrices, rather than numerical ones, so we do not address a condition number. We o#er a review of problems for which (algebraic) preconditioning is used, provide a bestiary of preconditioning problems, and discuss several preconditioner types to solve these problems. We present new conditioners, including conditioners to preserve low displacement rank for Toeplitzlike matrices. We also provide new analyses of preconditioner performance and results on the relations among preconditioning problems and with linear algebra problems. Thus improvements are offered for the e#ciency and applicability of preconditioners. The focus is on linear algebra problems over finite fields, but most results are valid for entries from arbitrary fields.
A study of Coppersmith's block Wiedemann algorithm using matrix polynomials
 LMCIMAG, REPORT # 975 IM
, 1997
"... We analyse a randomized block algorithm proposed by Coppersmith for solving large sparse systems of linear equations, Aw = 0, over a finite field K =GF(q). It is a modification of an algorithm of Wiedemann. Coppersmith has given heuristic arguments to understand why the algorithm works. But it was a ..."
Abstract

Cited by 29 (9 self)
 Add to MetaCart
(Show Context)
We analyse a randomized block algorithm proposed by Coppersmith for solving large sparse systems of linear equations, Aw = 0, over a finite field K =GF(q). It is a modification of an algorithm of Wiedemann. Coppersmith has given heuristic arguments to understand why the algorithm works. But it was an open question to prove that it may produce a solution, with positive probability, for small finite fields e.g. for K =GF(2). We answer this question nearly completely. The algorithm uses two random matrices X and Y of dimensions m \Theta N and N \Theta n. Over any finite field, we show how the parameters m and n of the algorithm may be tuned so that, for any input system, a solution is computed with high probability. Conversely, for certain particular input systems, we show that the conditions on the input parameters may be relaxed to ensure the success. We also improve the probability bound of Kaltofen in the case of large cardinality fields. Lastly, for the sake of completeness of the...
Lifting and recombination techniques for absolute factorization
 J. Complexity
, 2007
"... Abstract. In the vein of recent algorithmic advances in polynomial factorization based on lifting and recombination techniques, we present new faster algorithms for computing the absolute factorization of a bivariate polynomial. The running time of our probabilistic algorithm is less than quadratic ..."
Abstract

Cited by 23 (7 self)
 Add to MetaCart
Abstract. In the vein of recent algorithmic advances in polynomial factorization based on lifting and recombination techniques, we present new faster algorithms for computing the absolute factorization of a bivariate polynomial. The running time of our probabilistic algorithm is less than quadratic in the dense size of the polynomial to be factored.