Showing papers on "Breadth-first search published in 1994"
TL;DR: A distributed self-stabilizing Depth-First Search (DFS) spanning tree algorithm, whose output is a DFS spanning tree of the communication graph, kept in a distributed fashion.
142 citations
TL;DR: Evaluation for several adjacency maps shows that the conventional algorithm has the largest number of constraints, with a low degree of effort in derivation of adjacencies constraints and a small computational task to find a final solution.
Abstract: A mathematical programming formulation of the area-based forest planning problem can result in a large number of adjacency constraints with much potential for redundancy. Two heuristic algorithms have been proposed for reducing redundant adjacency constraints generated by the conventional algorithm. In this paper another analytical algorithm is proposed, and its efficiency and that of the conventional algorithm and the two heuristics are evaluated and compared. Comparison is based on the number of constraints, and on the computational effort needed both to derive the adjacency constraints and to solve the associated planning problem. Evaluation for several adjacency maps shows that the conventional algorithm has the largest number of constraints, with a low degree of effort in derivation of adjacency constraints and a small computational task to find a final solution. The first heuristic algorithm has the smallest number of constraints but involves a high degree of effort and a large computational task. T...
58 citations
23 May 1994
TL;DR: This work compares work-load balancing strategies of two depth-first searches and proposes a scheme that uses fine-grained fixed-sized work packets, which improves the global workload distribution from one iteration to the next and decreases with increasing search time.
Abstract: Among the various approaches for parallel depth-first search (DFS), the stack-splitting schemes are most popular. However, as shown in the paper, dynamical stack-splitting is not suitable for massively parallel systems with several hundred processors. Initial work-load imbalances and work packets of dissimilar sizes cause a high communication overhead. We compare work-load balancing strategies of two depth-first searches and propose a scheme that uses fine-grained fixed-sized work packets. In its iterative-deepening variant (named AIDA*) the global workload distribution improves from one iteration to the next. As a consequence, the communication overhead decreases with increasing search time. >
42 citations
TL;DR: This paper presents an O(n log log n) time algorithm for finding a depth-first search tree in a permutation graph and an O('n' time') algorithm forFinding a breadth-first Search Tree in apermutation graph.
23 citations
06 Nov 1994
TL;DR: The MEM execution model can be implemented in order to exploit a new kind of Parallelism, called path parallelism, which allows the parallel execution of unify operations related to simultaneously traversed paths.
Abstract: MEM (Multipath Execution Model) is a novel model for the execution of Prolog programs which combines a depth-first and breadth-first exploration of the search tree. The breadth-first search allows more than one path of the SLD-tree to be explored at the same time. In this way, the computational cost of traversing the whole search tree associated to a program can be decreased because the MEM model reduces the overhead due to the execution of control instructions and also diminishes the number of unifications to be performed. This paper focuses on the description of the MEM model and its sequential implementation. Moreover, the MEM execution model can be implemented in order to exploit a new kind of parallelism, called path parallelism, which allows the parallel execution of unify operations related to simultaneously traversed paths. >
7 citations
01 Jan 1994
TL;DR: Test results show that by using the described approach the theoretical and real speedups are larger than one and monotone increasing, and sometimes even superlinear.
Abstract: This paper describes the measures needed to improve the speedup of parallel branch-and-bound for mixed integer programming if we use the parallelism in the branch-and-bound tree. The machine model assumed is a distributed memory parallel computer. The program model is farmer-worker, in which the farmer creates the branch-and-bound tree, while the workers calculate the linear programming solution of the branch-and-bound nodes assigned to them by the farmer. We will see that for a depth first search we are able to guarantee the speedup to be larger than or equal to one, while superlinear speedup can still occur. The described measures to improve the speedup of the parallel branch-and-bound solver for mixed integer programming have been tested using problems from MIPlib. Test results show that by using the described approach the theoretical and real speedups are larger than one and monotone increasing, and sometimes even superlinear.
4 citations
01 Jan 1994
TL;DR: A new model for the execution of Prolog programs, called MEM (Multipath Execution Model), which combines a depth-first and breadth-first exploration of the search tree is presented, which reduces the computational cost of traversing the whole search tree associated to a program.
Abstract: A new model for the execution of Prolog programs, called MEM (Multipath Execution Model), which combines a depth-first and breadth-first exploration of the search tree is presented. The breadth-first search allows more than one path (multiple potential solutions) to be explored at the same time. In this way, the computational cost of traversing the whole search tree associated to a program can be decreased because the MEM model reduces the overhead due to the execution of control instructions. This paper focuses on the description of the MEM model and its sequential implementation. Moreover, the MEM execution model can easily extended to exploit a new kind of parallelism, called path parallelism, which allows the parallel execution of unify operations related to simultaneously explored paths. Since these operations do not have any dependence among them, this type of parallelism can always be exploited. An architecture (PMA) to implement the MEM execution model on a parallel environment is also presented. PMA looks like a SIMD machine, with a Control Processor (CP), responsible for traversing the whole search tree, and several Unification Functional Units (UFUs), responsible for performing unify operations.
2 citations
TL;DR: A fault-tolerant routing algorithm for star graph interconnection topology by using a depth-first search strategy and derives exact mathematical expressions for the probabilities that the algorithm will compute an optimal path for a given number of faulty links in the network.
TL;DR: A two level hierarchical representation of Cspace for robot path planning is developed to enhance the effectiveness of the path searching in Cspace, based on heuristic search which is applied for coarse representation.
TL;DR: This paper uses a machine model that performs (componentwise) bit vector operations (such as conjunction, comparison, etc.) in parallel and shows that the connected components of a graph G can be found in OB(n log n) steps serially, which performs better than the algorithm that is based on the depth first search.