Transitive Compaction in Parallel via Branchings
نویسندگان
چکیده
We study the following problem: given a strongly connected digraph, find a minimal strongly connected spanning subgraph of it. Our main result is a parallel algorithm for this problem, which runs in polylog parallel time and uses O(n) processors on a PRAM. Our algorithm is simple and the major tool it uses is computing a minimum-weight branching with zero-one weights. We also present sequential algorithms for the problem that run in time O(m + n ⋅ log n). * Supported in part by the International Computer Science Institute, Berkeley, California. † Also supported by NSF grant CCR-8411954. ‡ Also supported by Joint Services Electronics Program under N00014-84-C-0149. § Supported in part by NSF grant DCR-8605962 and ONR contract N00014-87-K-0467.
منابع مشابه
1-D Compaction
In this paper we consider the one-dimensional compaction prob· lem when the layout area contains forbidden regions and the layout components are allowed to move across these regions. Given n layout components and k forbidden regions, each of rectangular shape, we show how to solve this compaction problem in O(A) time with O(Cn + k) log k + 0 logo) preprocessing, where 6. and 6 are measures for ...
متن کاملCopolymerization of ethylene with α-olefins over highly active supported Ziegler-Natta catalyst with vanadium active component
The new highly active supported vanadium-magnesium catalyst (VMC) has been studied in α-olefin (1-butene, 1-hexene)/ ethylene copolymerization in the presence of hydrogen. Data on the effect of α-olefin/ethylene ratio in copolymerization on the content of branchings in copolymers, kinetic profile, copolymer yield, molecular weight and molecular weight distribution of copolymers have been obtain...
متن کاملLong-Distance Scrambling via Partial Compaction
In this paper, I propose a novel analysis of long-distance scrambling constructions in Japanese that is linguistically more adequate than those previously suggested in the literature. At the heart of my proposal is the view, suggested in Yatabe (1993a), that there is a theoretically signi cant parallelism between long-distance scrambling in Japanese and extraposition in languages like English. ...
متن کاملUsing the parallel complexity of programs to improve compaction
This paper focuses on the compaction of tail-recursive programs | arbitrary programs with condi-tionals, loops and function calls appearing in terminal position | for ne-grain parallel machines like VLIW or super-scalars. An iterative compaction method based on instruction move-up and fold/unfold transformations is studied. In order to speed-up compaction and produce shorter schedules, we propo...
متن کاملInK-Compact: In-Kernel Stream Compaction and Its Application to Multi-Kernel Data Visualization on General-Purpose GPUs
Stream compaction is an important parallel computing primitive that produces a reduced (compacted) output stream consisting of only valid elements from an input stream containing both invalid and valid elements. Computing on this compacted stream rather than the mixed input stream leads to improvements in performance, load balancing, and memory footprint. Stream compaction has numerous applicat...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- J. Algorithms
دوره 12 شماره
صفحات -
تاریخ انتشار 1991