1711053
Analyses for the Translation of OpenMP Codes into SPMD Style with Array Privatization
A so-called SPMD style OpenMP program can achieve scalability on ccNUMA systems by means of array privatization, and earlier research has shown good performance under this approach. Since it is hard to write SPMD OpenMP code, we showed a strategy for the automatic translation of many OpenMP constructs into SPMD style in our previous work. In this paper, we first explain how to interprocedurally detect whether the OpenMP program consistently schedules the parallel loops. If the parallel loops are consistently scheduled, we may carry out array privatization according to OpenMP semantics. We give two examples of code patterns that can be handled despite the fact that they are not consistent, and where the strategy used to translate them differs from the straightforward approach that can otherwise be applied.
6341849
Efficient Translation of OpenMP to Distributed Memory
The shared memory paradigm provides many benefits to the parallel programmer, particular with respect to applications that are hard to parallelize. Unfortunately, there are currently no efficient implementations of OpenMP for distributed memory platforms and this greatly diminishes its usefulness for real world parallel application development. In this paper we introduce a basic strategy for implementing OpenMP on distributed memory systems via a translation to Global Arrays. Global Arrays is a library of routines that provides many of the same features as OpenMP yet targets distributed memory platforms. Since it enables a reasonable translation strategy and also allows precise control over the movement of data within the resulting code, we believe it has the potential to provide higher levels of performance than the traditional translation of OpenMP to distributed memory via software distributed shared memory.
6253832
Towards a more efficient implementation of OpenMP for clusters via translation to global arrays
This paper discusses a novel approach to implementing OpenMP on clusters. Traditional approaches to do so rely on Software Distributed Shared Memory systems to handle shared data. We discuss these and then introduce an alternative approach that translates OpenMP to Global Arrays (GA), explaining the basic strategy. GA requires a data distribution. We do not expect the user to supply this; rather, we show how we perform data distribution and work distribution according to the user-supplied OpenMP static loop schedules. An inspector-executor strategy is employed for irregular applications in order to gather information on accesses to potentially non-local data, group non-local data transfers and overlap communications with local computations. Furthermore, a new directive INVARIANT is proposed to provide information about the dynamic scope of data access patterns. This directive can help us generate efficient codes for irregular applications using the inspector-executor approach. We also illustrate how to deal with some hard cases containing reshaping and strided accesses during the translation. Our experiments show promising results for the corresponding regular and irregular GA codes.
10777147
Circular Chromatic Numbers and Fractional Chromatic Numbers of Distance Graphs
This paper studies circular chromatic numbers and fractional chromatic numbers of distance graphsG(Z,D) for various distance setsD. In particular, we determine these numbers for thoseDsets of size two, for some specialDsets of size three, forD= {1, 2,···,m,n} with 1 ?m < n, forD= {q,q+1,···,p} withq
6825460
DynamicWorkflow Management Using Performance Data
An approach to dynamic workflow management and optimisation using performance data is presented. We discuss strategies for choosing an optimal service (based on user specified criteria) from several semantically equivalent Web Services. Such an approach involves finding "similar" services, by first pruning the set of discovered services based on service metadata, and subsequently selecting an optimal service based on data recorded during prior executions of a service and/or current machine loads. We describe the current implementation of the system, and demonstrate this by a BLAST (used in BioInformatics for Protein-alignment) example by using the Ganglia monitoring tool to get performance data.
39340000
Circular chromatic numbers of Mycielski's graphs
Abstract In a search for triangle-free graphs with arbitrarily large chromatic numbers, Mycielski developed a graph transformation that transforms a graph G into a new graph μ ( G ), we now call the Mycielskian of G , which has the same clique number as G and whose chromatic number equals χ ( G )+1. Let μ n ( G )= μ ( μ n −1 ( G )) for n ⩾2. This paper investigates the circular chromatic numbers of Mycielski's graphs. In particular, the following results are proved in this paper: (1)  for any graph G of chromatic number n, χ c (μ n−1 (G))⩽χ(μ n−1 (G))− 1 2 ; (2)  if a graph G satisfies χ c (G)⩽χ(G)− 1 d with d =2 or 3, then χ c (μ 2 (G))⩽χ(μ 2 (G))− 1 d ; (3)  for any graph G of chromatic number 3, χ c ( μ ( G ))= χ ( μ ( G ))=4; (4) χ c ( μ ( K n ))= χ ( μ ( K n ))= n +1 for n ⩾3 and χ c ( μ 2 ( K n ))= χ ( μ 2 ( K n ))= n +2 for n ⩾4.
2506060
Synchronous Binarization for Machine Translation
Systems based on synchronous grammars and tree transducers promise to improve the quality of statistical machine translation output, but are often very computationally intensive. The complexity is exponential in the size of individual grammar rules due to arbitrary re-orderings between the two languages, and rules extracted from parallel corpora can be quite large. We devise a linear-time algorithm for factoring syntactic re-orderings by binarizing synchronous rules when possible and show that the resulting rule set significantly improves the speed and accuracy of a state-of-the-art syntax-based machine translation system.
27213248
Multiresolution recognition of offline handwritten Chinese characters with wavelet transform
The authors propose a novel multiresolution recognition scheme for handwritten Chinese character recognition in which an input pattern is recognized by adopting the coefficients of the wavelet transforms. It is known that wavelet representation provides a coarse-to-fine strategy. The recognition starts from the coarse scale and moves to the finer scales. After preprocessing, the wavelet transform is applied to the kanji image. Then, we make use of the coefficients with the lowest resolution to select 50 candidates from 3755 categories. In order to enhance the statistical feature of a character, we used statistical methods to reconstruct features in fine classification. With the proposed recognition system, experiments are performed on the 863 Testing System. The correct rate reaches 80.56%, which is a promising result.