Implementing a High-Level Distributed-Memory Parallel Haskell in Haskell

2012 ◽  
pp. 35-50 ◽  
Author(s):  
Patrick Maier ◽  
Phil Trinder
Keyword(s):  
Distributed Memory ◽  
High Level

scholarly journals Algorithm Development for Distributed Memory Multicomputers Using CONLAB

1992 ◽  
Vol 1 (2) ◽  
pp. 185-203 ◽  
Author(s):  
Peter Jacobson ◽  
Bo Kågström ◽  
Mikael Rännar
Keyword(s):  
Distributed Memory ◽  
Computer Architectures ◽  
Parallel Computer ◽  
Levels Of Abstraction ◽  
Wide Audience ◽  
Development Methodology ◽  
Target Architecture ◽  
Real Performance ◽  
High Level ◽  
Different Levels

CONLAB (CONcurrent LABoratory) is an environment for developing algorithms for parallel computer architectures and for simulating different parallel architectures. A user can experimentally verify and obtain a picture of the real performance of a parallel algorithm executing on a simulated target architecture. CONLAB gives a high-level support for expressing computations and communications in a distributed memory multicomputer (DMM) environment. A development methodology for DMM algorithms that is based on different levels of abstraction of the problem, the target architecture, and the CONLAB language itself is presented and illustrated with two examples. Simulotion results for and real experiments on the Intel iPSC/2 hypercube are presented. Because CONLAB is developed to run on uniprocessor UNIX workstations, it is an educational tool that offers interactive (simulated) parallel computing to a wide audience.

scholarly journals Efficient Parallel Programming with Linda

1992 ◽  
Vol 1 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Ashish Deshpande ◽  
Martin Schultz
Keyword(s):  
Parallel Programming ◽  
Programming Language ◽  
Associative Memory ◽  
Shallow Water Equations ◽  
Distributed Memory ◽  
Parallel Machines ◽  
Yale University ◽  
Coordination Language ◽  
High Level ◽  
Memory Architectures

Linda is a coordination language inverted by David Gelernter at Yale University, which when combined with a computation language (like C) yields a high-level parallel programming language for MIMD machines. Linda is based on a virtual shared associative memory containing objects called tuples. Skeptics have long claimed that Linda programs could not be efficient on distributed memory architectures. In this paper, we address this claim by discussing C-Linda's performance in solving a particular scientific computing problem, the shallow water equations, and make comparisons with alternatives available on various shared and distributed memory parallel machines.

scholarly journals Update-in-Place Analysis for True Multidimensional Arrays

1996 ◽  
Vol 5 (2) ◽  
pp. 147-160 ◽  
Author(s):  
Steven M. Fitzgerald ◽  
Rodney R. Oldehoeft
Keyword(s):  
Side Effects ◽  
Execution Time ◽  
Distributed Memory ◽  
Parallel Architectures ◽  
New Method ◽  
Software Systems ◽  
Time Analysis ◽  
Multidimensional Arrays ◽  
Applicative Language ◽  
High Level

Applicative languages have been proposed for defining algorithms for parallel architectures because they are implicitly parallel and lack side effects. However, straightforward implementations of applicative-language compilers may induce large amounts of copying to preserve program semantics. The unnecessary copying of data can increase both the execution time and the memory requirements of an application. To eliminate the unnecessary copying of data, the Sisal compiler uses both build-in-place and update-in-place analyses. These optimizations remove unnecessary array copy operations through compile-time analysis. Both build-in-place and update-in-place are based on hierarchical ragged arrays, i.e., the vector-of-vectors array model. Although this array model is convenient for certain applications, many optimizations are precluded, e.g., vectorization. To compensate for this deficiency, new languages, such as Sisal 2.0, have extended array models that allow for both high-level array operations to be performed and efficient implementations to be devised. In this article, we introduce a new method to perform update-in-place analysis that is applicable to arrays stored either in hierarchical or in contiguous storage. Consequently, the array model that is appropriate for an application can be selected without the loss of performance. Moreover, our analysis is more amenable for distributed memory and large software systems.

CuSP

2021 ◽  
Vol 55 (1) ◽  
pp. 47-60
Author(s):  
Loc Hoang ◽  
Roshan Dathathri ◽  
Gurbinder Gill ◽  
Keshav Pingali
Keyword(s):  
Single Machine ◽  
Distributed Memory ◽  
The State ◽  
Main Memory ◽  
Input Graph ◽  
Large Graphs ◽  
Graph Analytics ◽  
Graph Partitions ◽  
High Level ◽  
Edge Partitioning

Graph analytics systems must analyze graphs with billions of vertices and edges which require several terabytes of storage. Distributed-memory clusters are often used for analyzing such large graphs since the main memory of a single machine is usually restricted to a few hundreds of gigabytes. This requires partitioning the graph among the machines in the cluster. Existing graph analytics systems use a built-in partitioner that incorporates a particular partitioning policy, but the best policy is dependent on the algorithm, input graph, and platform. Therefore, built-in partitioners are not sufficiently flexible. Stand-alone graph partitioners are available, but they too implement only a few policies. CuSP is a fast streaming edge partitioning framework which permits users to specify the desired partitioning policy at a high level of abstraction and quickly generates highquality graph partitions. For example, it can partition wdc12, the largest publicly available web-crawl graph with 4 billion vertices and 129 billion edges, in under 2 minutes for clusters with 128 machines. Our experiments show that it can produce quality partitions 6× faster on average than the state-of-theart stand-alone partitioner in the literature while supporting a wider range of partitioning policies.

Transcription factor/DNA interactions visualized by electron spectroscopic imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 450-451
Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown
Keyword(s):  
Transcription Factor ◽  
Dna Sequences ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Phosphorus Content ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
Dna Backbone ◽  
Two Parameters ◽  
High Level

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.

Advances in Stem Instrumentation for Biology

1990 ◽  
Vol 48 (1) ◽  
pp. 362-363
Author(s):  
J. S. Wall
Keyword(s):  
Scanning Transmission Electron Microscope ◽  
Carbon Films ◽  
Specimen Preparation ◽  
Material Deposition ◽  
Active User ◽  
Percent Improvement ◽  
Scanning Transmission ◽  
The Moment ◽  
Film Substrate ◽  
High Level

The forte of the Scanning transmission Electron Microscope (STEM) is high resolution imaging with high contrast on thin specimens, as demonstrated by visualization of single heavy atoms. of equal importance for biology is the efficient utilization of all available signals, permitting low dose imaging of unstained single molecules such as DNA.Our work at Brookhaven has concentrated on: 1) design and construction of instruments optimized for a narrow range of biological applications and 2) use of such instruments in a very active user/collaborator program. Therefore our program is highly interactive with a strong emphasis on producing results which are interpretable with a high level of confidence.The major challenge we face at the moment is specimen preparation. The resolution of the STEM is better than 2.5 A, but measurements of resolution vs. dose level off at a resolution of 20 A at a dose of 10 el/A2 on a well-behaved biological specimen such as TMV (tobacco mosaic virus). To track down this problem we are examining all aspects of specimen preparation: purification of biological material, deposition on the thin film substrate, washing, fast freezing and freeze drying. As we attempt to improve our equipment/technique, we use image analysis of TMV internal controls included in all STEM samples as a monitor sensitive enough to detect even a few percent improvement. For delicate specimens, carbon films can be very harsh-leading to disruption of the sample. Therefore we are developing conducting polymer films as alternative substrates, as described elsewhere in these Proceedings. For specimen preparation studies, we have identified (from our user/collaborator program ) a variety of “canary” specimens, each uniquely sensitive to one particular aspect of sample preparation, so we can attempt to separate the variables involved.

A Questionnaire Survey of Current Rehabilitation Practices for Adults With Normal Hearing Sensitivity Who Experience Auditory Difficulties

2020 ◽  
Vol 29 (4) ◽  
pp. 738-761
Author(s):  
Tess K. Koerner ◽  
Melissa A. Papesh ◽  
Frederick J. Gallun
Keyword(s):  
Hearing Aids ◽  
Questionnaire Survey ◽  
Patient Population ◽  
Clinical Care ◽  
Normal Hearing ◽  
Auditory Training ◽  
Training Methods ◽  
Hearing Sensitivity ◽  
Considerable Benefit ◽  
High Level

Purpose A questionnaire survey was conducted to collect information from clinical audiologists about rehabilitation options for adult patients who report significant auditory difficulties despite having normal or near-normal hearing sensitivity. This work aimed to provide more information about what audiologists are currently doing in the clinic to manage auditory difficulties in this patient population and their views on the efficacy of recommended rehabilitation methods. Method A questionnaire survey containing multiple-choice and open-ended questions was developed and disseminated online. Invitations to participate were delivered via e-mail listservs and through business cards provided at annual audiology conferences. All responses were anonymous at the time of data collection. Results Responses were collected from 209 participants. The majority of participants reported seeing at least one normal-hearing patient per month who reported significant communication difficulties. However, few respondents indicated that their location had specific protocols for the treatment of these patients. Counseling was reported as the most frequent rehabilitation method, but results revealed that audiologists across various work settings are also successfully starting to fit patients with mild-gain hearing aids. Responses indicated that patient compliance with computer-based auditory training methods was regarded as low, with patients generally preferring device-based rehabilitation options. Conclusions Results from this questionnaire survey strongly suggest that audiologists frequently see normal-hearing patients who report auditory difficulties, but that few clinicians are equipped with established protocols for diagnosis and management. While many feel that mild-gain hearing aids provide considerable benefit for these patients, very little research has been conducted to date to support the use of hearing aids or other rehabilitation options for this unique patient population. This study reveals the critical need for additional research to establish evidence-based practice guidelines that will empower clinicians to provide a high level of clinical care and effective rehabilitation strategies to these patients.

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