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Bayesian Classification (AutoClass): Theory and Results   (package: autoclass)
We describe AutoClass, an approach to unsupervised classification based upon the classical mixture model, supplemented by a Bayesian method for determining the optimal classes. We include a moderately detailed exposition of the mathematics behind the AutoClass system. We emphasize that no current unsupervised classification system can produce maximally useful results when operated alone. It is the interaction between domain experts and the machine searching over the model space, that generates new knowledge. Both bring unique information and abilities to the database analysis task, and each enhances the others' effectiveness. We illustrate this point with several applications of AutoClass to complex real world databases, and describe the resulting successes and failures.

Bayesian Classification Theory   (package: autoclass)
The task of inferring a set of classes and class descriptions most likely to explain a given data set can be placed on a firm theoretical foundation using Bayesian statistics. Within this framework, and using various mathematical and algorithmic approximations, the AutoClass system searches for the most probable classifications, automatically choosing the number of classes and complexity of class descriptions. A simpler version of AutoClass has been applied to many large real data sets, have discovered new independently-verified phenomena, and have been released as a robust software package. Recent extensions allow attributes to the selectively correlated within particular classes, and allow classes to inherit, or share, model parameters through a class hierarchy. In this paper we summarize the mathematical foundations of Autoclass.

Hypre High-Performance Preconditioners   (package: hypre-doc)
HYPRE is a software library for solving large, sparse linear systems of equations on massively parallel computers. The library was created with the primary goal of providing users with advanced parallel preconditioners. Issues of robustness, ease of use, flexibility, and interoperability also play an important role.



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