snowFT-package(snowFT)
snowFT-package()所属R语言包：snowFT
Fault Tolerant Simple Network of Workstations
容错简单的网络工作站
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Extension of the snow package supporting fault tolerant and reproducible applications, as well as supporting easy-to-use parallel programming - only one function is needed. It supports the PVM, MPI as well as the socket communication layers.
扩展的雪包，支持容错和可重复性的应用程序，以及支持易于使用的并行编程 - 只有一个功能是需要的。它支持PVM，MPI以及套接字通信层。
Details
详细信息----------Details----------
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The main function of this package, performParallel, handles all tasks that are necessary for evaluating a user-defined function in parallel. These include creating a cluster, initializing nodes, handling a random number generator, processing the given function on the cluster and cleaning up. In the very basic settings (i.e. when using with the socket layer), no additional software is necessary. The package can be used on a single multi-processor/core machine, homogeneous cluster, or a heterogeneous group of computers.
这个软件包的主要功能，performParallel，是必要的，以评估一个用户定义的函数并行处理所有的任务。这些包括创建一个聚类，初始化节点，处理一个随机数发生器，聚类上的处理给定的函数，和清理。在基本设置（即使用套接字层），无需额外的软件是必要的。该软件包可用于上一个单一的multi-processor/core机，同构聚类，或一组异质性的计算机。
The package supports creating and handling a snow cluster that is: <ol> Fault tolerant: The master checks repeatedly for failures in its waiting time and initiates a failure recovery if needed.
包支持创建和处理一个snow聚类中的：<OL>故障容错：主多次的失败在等待时间和检查，如果需要的话，启动故障恢复。
Load balanced AND produces reproducible results: one stream of random numbers associated with one replicate (instead of one stream per node as handled by snow).
负载平衡和可重复的结果：一个流与一个复制（而不是一个流作为处理snow），每个节点的随机数。
Computationally transparent: Currently processed replicates and failed replicates stored into files. Allows defining a function that is called after each given number of replicates.
计算透明：当前处理的重复和失败的重复存储到文件中。允许定义一个函数被调用后，每一个给定数量的复制。
Dynamically resizeable: The cluster size is stored in a file which is read by the master repeatedly. In case of a modification the cluster is updated.
动态可调整大小的簇的大小被存储在一个文件中被反复读取的主。在一个变形例的情况下，聚类中的更新。
No administration overhead: All administration is managed by the master in its waiting time. (Note that there is a time-overhead for creating and destroying the cluster, as well as the RNG initialization. Thus, simple operations, such as the example below, will not gain from running in parallel.)
没有管理开销：所有的管理是由它的主人在等待时间。 （请注意，有时间开销用于创建和销毁聚类，以及到RNG初始化，因此，简单的操作，如下面的例子中，将不会获得从并行运行。）
Allows running processes sequentially with the same random numbers as it would in parallel. Thus, results can be compared between the two modes.
允许使用相同的随机数，因为它会在并行运行的进程顺序。因此，结果可以在两种模式之间进行比较。
Easy to use: All features, including creating the cluster, RNG initialization and clean-up, are available through one single function - performParallel. </ol> Note that not all features are available for all communication layers. The fault tolerance is currently available only for PVM. Dynamic resizing is not available for MPI.
易于使用的所有功能，包括创建聚类，RNG初始化和清理，都可以通过一个单一的功能 - performParallel。 </ OL>请注意，并非所有的功能都可用的所有通信层。目前仅适用于PVM的容错能力。动态调整大小是不为MPI。
（作者）----------Author(s)----------
Hana Sevcikova, A. J. Rossini
Maintainer: Hana Sevcikova <hanas@uw.edu>
参考文献----------References----------
http://www.stat.washington.edu/hana/parallel/snowFT-doc.pdf
参见----------See Also----------
performParallel, clusterCall
performParallel，clusterCall
实例----------Examples----------
## Not run: [＃不运行：]
# generates 500 times 1000 normally distributed random numbers on 5 nodes[1000正态分布的随机数产生500倍的5个节点]
# (all localhost)[（所有本地）]
res <- performParallel(5, rep(1000, 500), fun=rnorm, cltype='SOCK')
print(mean(unlist(res)))
## End(Not run)[＃（不执行）]
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注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
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发表于 2012-9-30 11:06:03
