Analysing probabilistically constrained optimism

Abstract

In previous work we presented the DTRD algorithm, an optimistic synchronization algorithm for parallel discrete event simulation of multi‐agent systems, and showed that it outperforms Time Warp and time windows on a range of test cases. DTRD uses a decision‐theoretic model of rollback to derive an optimal time to delay read event so as to maximize the rate of LVT progression. The algorithm assumes that the inter‐arrival times (both virtual and real) of events are normally distributed. In this paper we present a more detailed evaluation of the DTRD algorithm, and specifically how the performance of the algorithm is affected when the inter‐arrival times do not follow the assumed distributions. Our analysis suggests that the performance of the algorithm is relatively insensitive to events whose inter‐arrival times are not normally distributed. However, as the variance of event inter‐arrival times increases, its performance degrades to that of Time Warp. The evaluation approach we present is generally applicable, and we sketch how a similar analysis may be performed for two other decision‐theoretic optimistic synchronization algorithms. Copyright © 2009 John Wiley & Sons, Ltd.

Interfacing multi-agent models to distributed simulation platforms: The case of PDES-MAS

“…PDES-MAS uses optimistic synchronisation. Synchronisation algorithms that have developed for PDES-MAS as reported in the wors of (Lees, Logan, and Theodoropoulos 2003), (Lees, Logan, and Theodoropoulos 2004), (Lees et al 2005), (Lees et al 2006a), (Lees et al 2006b), (Lees, Logan, and Theodoropoulos 2008), and (Lees, Logan, and Theodoropoulos 2009). In general, each SSV is associated with a list of Write Periods representing the values taken by the variable at different logical times through the simulation.…”

Using Access Patterns to Analyze the Performance of Optimistic Synchronization Algorithms in Simulations of MAS

“…To address these issues, we developed the PDES-MAS framework for the simulation of multi-agent systems [7,[14][15][16][17][18][19]. PDES-MAS adopts a standard parallel discrete event approach.…”

“…exponential distributions) are therefore not necessarily appro-priate models of a situated MAS. See [19] for an evaluation of the performance of DTRD in simulations where the real and virtual inter-arrival times are not normally distributed.…”