PARALLEL ALGORITHMS FOR SOME DOMINANCE PROBLEMS BASED ON THE PRAM MODEL

1993 ◽  
Vol 03 (04) ◽  
pp. 367-382
Author(s):  
I.W. CHAN ◽  
D.K. FRIESEN
Keyword(s):  
Computational Model ◽  
Single Point ◽  
Random Access ◽  
Geometric Algorithms ◽  
Counting Problem ◽  
Erew Pram ◽  
Pram Model ◽  
Input Size ◽  
Parallel Random Access Machine ◽  
Direct Dominance

Two parallel geometric algorithms based on the idea of point domination are presented. The first algorithm solves the d-dimensional isothetic rectangles intersection counting problem of input size N/2d, where d>1 and N is a multiple of 2d, in O( log d−1 N) time and O(N log N) space. The second algorithm solves the direct dominance reporting problem for a set of N points in the plane in O( log N+J) time and O(N log N) space, where J denotes the maximum of the number of direct dominances reported by any single point in the set. Both algorithms make use of the EREW PRAM (Exclusive Read Exclusive Write Parallel Random Access Machine) consisting of O(N) processors as the computational model.

A Simple Optimal Parallel Algorithm for Reporting Paths in a Tree

1997 ◽  
Vol 07 (01) ◽  
pp. 3-11 ◽  
Author(s):  
Andrzej Lingas ◽  
Anil Maheshwari
Keyword(s):  
Parallel Algorithm ◽  
Random Access ◽  
Input Tree ◽  
Single Pair ◽  
Random Access Machine ◽  
Erew Pram ◽  
Parallel Random Access Machine ◽  
Path Queries

We present optimal parallel solutions to reporting paths between pairs of nodes in an n-node tree. Our algorithms are deterministic and designed to run on an exclusive read exclusive write parallel random-access machine (EREW PRAM). In particular, we provide a simple optimal parallel algorithm for preprocessing the input tree such that the path queries can be answered efficiently. Our algorithm for preprocessing runs in O( log n) time using O(n/ log n) processors. Using the preprocessing, we can report paths between k node pairs in O( log n + log k) time using O(k + (n + S)/ log n) processors on an EREW PRAM, where S is the size of the output. In particular, we can report the path between a single pair of distinct nodes in O( log n) time using O(L/ log n) processors, where L denotes the length of the path.

ON OPTIMAL OROW-PRAM ALGORITHMS FOR COMPUTING RECURSIVELY DEFINED FUNCTIONS

1995 ◽  
Vol 05 (02) ◽  
pp. 299-309
Author(s):  
ROLF NIEDERMEIER ◽  
PETER ROSSMANITH
Keyword(s):  
Parallel Algorithms ◽  
Computational Model ◽  
Random Access ◽  
Erew Pram

We investigate parallel algorithms to compute recursively defined functions. Our computational model are parallel random access machines (PRAM's). We preferably make use of the OROW-PRAM (owner read, owner write), a model supposed to be even weaker and more realistic than the EREW-PRAM (exclusive read, exclusive write) and that still provides the opportunities of a completely connected processor network. For OROW-PRAM's we show that our parallel algorithms are work-optimal.

ON THE PERFORMANCE AND COST OF SOME PRAM MODELS ON CMP HARDWARE

2010 ◽  
Vol 21 (03) ◽  
pp. 387-404 ◽  
Author(s):  
MARTTI FORSELL
Keyword(s):  
Random Access ◽  
Chip Multiprocessor ◽  
Pram Model ◽  
Vlsi Technology ◽  
Cost Efficient ◽  
Performance Area ◽  
And Performance ◽  
On Chip ◽  
Parallel Random Access Machine ◽  
The Cost

The Parallel Random Access Machine is a very strong model of parallel computing that has resisted cost-efficient implementation attempts for decades. Recently, the development of VLSI technology has provided means for indirect on-chip implementation, but there are different variants of the PRAM model that provide different performance, area and power figures and it is not known how their implementations compare to each others. In this paper we measure the performance and estimate the cost of practical implementations of four PRAM models including EREW, Limited Arbitrary CRCW, Full Arbitrary CRCW, Full Arbitrary Multioperation CRCW on our Eclipse chip multiprocessor framework. Interestingly, the most powerful model shows the lowest simulation cost and highest performance/area and performance/power figures.

A PRACTICAL PLATFORM FOR CREW EMULATION

1993 ◽  
Vol 03 (02) ◽  
pp. 139-145 ◽  
Author(s):  
PETER J. LOOGES ◽  
STEPHAN OLARIU
Keyword(s):  
Lower Bounds ◽  
Random Access ◽  
Technology Support ◽  
Development Tool ◽  
Pram Model ◽  
Vlsi Technology ◽  
Crew Pram ◽  
Cmos Vlsi ◽  
Parallel Random Access Machine ◽  
Crossbar Network

The Parallel Random Access Machine or PRAM model, has been a much employed parallel algorithm development tool for a number of years. As such, many important problems have been solved on this model. Accordingly, considerable attention has been given to the process of simulating PRAM models on more realistic architectures. The purpose of this paper is to present an efficient simulation of the Concurrent Read Exclusive Write PRAM model by the crossbar connected machine (CCM). In addition to simulation, it is proven that all lower bounds for the CREW PRAM directly apply to the CCM. This is the first presentation of algorithmic lower bounds for a crossbar based model. The buses of the network are assumed to have a broadcast delay of δ(n). Recent implementations of the crossbar network in CMOS VLSI technology support the viability of the CCM model. It is the communication flexibility of the crossbar network which supports the PRAM simulations in a very straightforward manner without the complex interconnection systems or high overhead algorithms of many prior simulations.

scholarly journals PRAM MEMORY ALLOCATION AND INITIALIZATION

1993 ◽  
Vol 03 (03) ◽  
pp. 291-299 ◽  
Author(s):  
LISA HIGHAM ◽  
ERIC SCHENK
Keyword(s):  
Random Access ◽  
Constant Factor ◽  
The Other ◽  
Memory Allocation ◽  
Random Access Machine ◽  
Erew Pram ◽  
Crew Pram ◽  
Parallel Random Access Machine

Two techniques for managing memory on a parallel random access machine (PRAM) are presented. One is a scheme for an n/log n processor EREW PRAM that dynamically allocates and deallocates up to n records of the same size in O(log n) time. The other is a simulation of a PRAM with initialized memory by one with uninitialized memory. A CREW PRAM variant of the technique justifies the assumption that memory can be assumed to be appropriately initialized with no asymptotic increase in time but a factor of n increase in space. An EREW PRAM solution incurs a factor of O(log n) increase in time but only a constant factor increase in space.

Transforming comparison model lower bounds to the parallel-random-access-machine

1997 ◽  
Vol 62 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Dany Breslauer ◽  
Artur Czumaj ◽  
Devdatt P. Dubhashi ◽  
Friedhelm Meyer auf der Heide
Keyword(s):  
Lower Bounds ◽  
Random Access ◽  
Comparison Model ◽  
Random Access Machine ◽  
Parallel Random Access Machine

SUB-LOGARITHMIC ALGORITHMS FOR THE LARGEST EMPTY RECTANGLE PROBLEM

1993 ◽  
Vol 03 (01) ◽  
pp. 79-85
Author(s):  
STEPHAN OLARIU ◽  
WENHUI SHEN ◽  
LARRY WILSON
Keyword(s):  
Parallel Algorithms ◽  
Erew Pram ◽  
Pram Model ◽  
The Common ◽  
Crcw Pram ◽  
Natural Way

We show that the Largest Empty Rectangle problem can be solved by reducing it, in a natural way, to the All Nearest Smaller Values problem. We provide two classes of algorithms: the first one assumes that the input points are available sorted by x (resp. y) coordinate. Our algorithm corresponding to this case runs in O(log log n) time using [Formula: see text] processors in the Common-CRCW-PRAM model. For unsorted input, we present algorithms that run in [Formula: see text] time using [Formula: see text] processors in the Common-CRCW-PRAM, or in O( log n) time using [Formula: see text] processors in the EREW-PRAM model. No sub-logarithmic time parallel algorithms have been previously reported for this problem.

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