Traces can be viewed as parallel processes and the "mean speedup" of a trace monoid has been introduced as a measure of "intrinsic parallelism" of the monoid. We study the problem of computing the mean speedup under two conditions: uniform distribution on the words of given length and uniform distribution on the traces of given height. In the first case, we give an approximability result showing a probabilistic fully polynomial time approximation scheme, while, in the second case, we prove that the problem is NP-hard to approximate within n1-c for every ∊ > 0, unless NP = coR. A further consequence is the hardness of the problem of generating traces of a given height uniformly at random.
Approximating the mean speedup in trace monoids / A. Bertoni, R. Radicioni. - In: INTERNATIONAL JOURNAL OF FOUNDATIONS OF COMPUTER SCIENCE. - ISSN 0129-0541. - 19:3(2008 Jun), pp. 497-511.
Titolo: | Approximating the mean speedup in trace monoids | |
Autori: | BERTONI, ALBERTO (Primo) RADICIONI, ROBERTO (Ultimo) | |
Parole Chiave: | Trace monoids ; concurrent systems ; mean speedup ; uniform random generation | |
Settore Scientifico Disciplinare: | Settore INF/01 - Informatica | |
Data di pubblicazione: | giu-2008 | |
Rivista: | ||
Tipologia: | Article (author) | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1142/S0129054108005796 | |
Appare nelle tipologie: | 01 - Articolo su periodico |