Composition of Efficient Nested BSP Algorithms: Minimum Spanning Tree Computation as an Instructive Example

We report on the results of an automatic configuration approach for implementing complex parallel BSP algorithms. For this approach, a parallel algorithm is described by a sequence of instructions and of subproblems that have to be solved by other parallel algorithms called as subroutines, together with a mathematical description of its own running time. There also may be free algorithmic parameters as, e. g., the degree of trees in used data structures that have an impact on the running time. As the running time of an algorithm depends on several machine parameters, on some fixed and on the choice of the free algorithmic parameters and on the choice of the parallel subroutines for which the same statement applies in turn, the actual composition of the parallel program for an actual parallel machine from all these ingredients is a difficult task. We have implemented such a configuration system using the Paderborn University BSP library and present as an instructive example the theoretical and experimental results of implementations of sophisticated minimum spanning tree algorithms.

Feasability, Portability, Predictability and Efficiency : Four Ambitious Goals for the Design and Implementation of Parallel Coarse Grained Graph Algorithms

We study the relationship between the design and analysis of graph algorithms in the coarsed grained parallel models and the behavior of the resulting code on todays parallel machines and clusters. We conclude that the coarse grained multicomputer model (CGM) is well suited to design competitive algorithms, and that it is thereby now possible to aim to develop portable, predictable and efficient parallel algorithms code for graph problems

Practical Parallel Algorithms for Minimum Spanning Trees

We study parallel algorithms for computing the minimum spanning tree of a weighted undirected graph G with n vertices and m edges. We consider an input graph G with m=n p, where p is the number of processors. For this case, we show that simple algorithms with dataindependent communication patterns are efficient, both in theory and in practice. The algorithms are evaluated theoretically using Valiant's BSP model of parallel computation and empirically through implementation results