The lid method for exhaustive exploration of metastable states of complex systems

The `lid' algorithm performs an exhaustive exploration of neighborhoods of local energy minima of energy landscapes. This paper describes an implementation of the algorithm, including issues of parallel performance and scalability. To illustrate the versatility of the approach and to stress the common features present in landscapes of quite different systems, we present selected results for 1) a spin glass, 2) a ferromagnet, 3) a covalent network model for glassy systems, and 4) a polymer. The exponential nature of the local density of states found in these systems and its relation to the ordering transition is briefly commented upon.Comment: RevTeX, 11 pages, 1 figur

Asynchronous Parallel Construction of Recursive Tree Hierarchies

. Multi-resolution methods are widely used in scientific visualization, image processing, and computer graphics. While many applications only require an one-time construction of these data-structures which can be done in a preprocess, this pre-process can take a significant amount of time. Considering large datasets, this time consumption can range from several minutes up to several hours, especially if this pre-process is frequently needed. Furthermore, numerous new applications, such as visibility queries, arise which often need a dynamic reconstruction of a scene database. In this paper, we address several problems of the construction or reconstruction of recursive tree hierarchies in parallel. In particular, we focus on parallel dynamic memory allocation and the associated synchronization overhead. Keywords: Parallel hierarchies, recursive tree structures, octrees, memory synchronization, shared memory, thread model. 1 Introduction In computer graphics, hierarchical m..

Mailing List Archive Tools

Electronic mailing lists are a common forum for discussion on the Internet. Each participant receives a copy of each message posted to the list with an additional copy typically archived at a well-known site for later retrieval. Busy lists and long-running lists can quickly accumulate many messages making it difficult to locate information. Few sites provide mechanisms for the efficient storage or retrieval of information from these archives. The Mailing List Archive (MLA) tools were designed to address these issues. Mail messages are stored in a space-efficient manner and the archive information is processed to create a database that is optimized for fast queries. The MLA tools are designed for use as Computer Gateway Interface (CGI) applications so that archives can be accessed through HTML forms on the World Wide Web. Concurrent update and retrieval are an integral part of the design so that up to date information is always returned in query results. 1.0 Introduction UNIX mailing l..