@inproceedings{e959c9208795434596b1b934f3f51d2b,
title = "Bounds on parallel computation of multivariate polynomials",
abstract = "We consider the problem of fast parallel evaluation of multivariate polynomials over a field F. We define “maximal-degree” (maxdeg) of a multivariate polynomial f as maxi degxi(f(xi,⋯,xn)) i=1,⋯, n. The first lower bound result states that if a circut G evaluates a multivariate polynomial f, where its nodes are capable of performing (+,*), then the depth(G) is not less than log2[maxdeg(f)]. This result is a generalization of Kung{\textquoteright}s[K] results for a univariate polynomial which is log2 [deg f]. In the second part, we consider the circuit G which evaluates an arbitrary polynomial f in n variables with maxdeg(f)≜dp>1. We present two algorithms that achieve better performance than the classical results of Hyafil[H] and Valiant et al. [VSBR] for most classes of multivariate polynomials. For the class of” dense” polynomials the results are closed to the theorethical bound log C, where C is the sequential complexity.The algorithms generalize Munro-Paterson[MP] method for the univariate case. It should be noticed that the bound obtained by Hyafil[H] and Valiant, Skyum, Berkowitz and Rackoff[VSBR] is not sufficiently tight for the worst-sequential case (dense multivariate polynomials) and their bound can be reduced by the factor of log d while the number of required processors is only O(C). The best improvement is achieved in a case of a”dense” multivariate polynomial. A polynomial is dense if the computation necessitates Ω(dnp) sequential steps. The simple algorithm requires only n log dp+O(n√log dp) parallel steps The second algorithm has parallel complexity, measured by the depth of the circuit, depth(G) ≤ n(log dp+β)+log n+√log dp where β ≤ √log dp. If C=Ω(dnp) then it is less than log C+√n log C where C is the number of sequential steps, and it requires only O(C) processors. The second algorithm is slightly better than the” simple” one. The improvement is achieved when β is small. The improvement of both algorithms in the parallel complexity and the number of processors with respect to Valiant is significant for most classes of multivariate polynomials.",
keywords = "Complexity of parallel computation, Dense polynomial, Design and analysis of parallel algorithms, Maximal-degree, Multivariate polynomials",
author = "Ilan Sade and Amir Averbuch",
note = "Publisher Copyright: {\textcopyright} Springer-Verlag Berlin Heidelberg 1992.; null ; Conference date: 27-05-1992 Through 28-05-1992",
year = "1992",
doi = "10.1007/bfb0035174",
language = "אנגלית",
isbn = "9783540555537",
series = "Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)",
publisher = "Springer Verlag",
pages = "147--153",
editor = "Danny Dolev and Zvi Galil and Zvi Galil and Michael Rodeh",
booktitle = "Theory of Computing and Systems - ISTCS 1992, Israel Symposium, Proceedings",
}