Implementation of a Binary Tree Driver (OAKc) in Cactus

Cactus Code is an open source framework designed primarily for scientists and engineers, in which the core or “flesh” acts as a central unit to which external modules or “thorns” can interface. Cactus is used on many different architectures and can be used to implement different codes from various disciplines. While initially developed for solving problems in numerical relativity, it has since expanded to include thorns for computational fluid dynamics, climate modeling and bioinformatics. Binary trees are fast insert and lookup recursive data structures with at most two children at each node. Many different applications use binary tree structures for the efficiency they provide; including high performance databases, visualization hierarchies, discrete mathematics, Monte Carlo simulations, logic programming and computational econometrics. This paper discusses the design and implementation of binary trees in Cactus, which will then provide capabilities for new application domains. The core module discussed here is special in that it can allocate binary tree nodes for other thorns to use, in effect realizing the role of a Cactus driver thorn. Due to the high computational loads involved in most real world problems, one basic requirement of this binary tree driver is parallelism to make use of high performance computing environments.