pphindcast2d(SpatialVx)
pphindcast2d()所属R语言包：SpatialVx
Function to perform the practically perfect hindcast neighborhood verification method
要执行的功能完善后报区实际验证方法
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Function to perform the practically perfect hindcast neighborhood verification method. Finds the optimal threhsold, Pthresh, and calculates the desired statistic for that threshold.
要执行的功能完善后报区实际验证方法。找出最优threhsold，Pthresh，并计算该阈值所需的统计。
用法----------Usage----------
pphindcast2d(obj, which.score = "ets", verbose = FALSE, ...)
参数----------Arguments----------
参数：obj
A list object returned by the hoods2dPrep function.
hoods2dPrep函数返回一个列表对象。
参数：which.score
character stating which verification score is to be used. Must be one that is accepted by vxstats.
字符，说明是要使用的验证得分。必须是所接受的vxstats。
参数：verbose
logical, should progress information be printed ot the screen?
逻辑的发展，应以信息印ot的屏幕吗？
参数：...
optional arguments to the optim function. May not include lower, upper or method as these are hard coded into the function.
optim功能的可选参数。可能不包含下方，上方或方法，因为这些都是硬编码的功能。
Details
详细信息----------Details----------
The practically perfect hindcast method is described in Ebert (2008). Using a similar notation as that described therein (and in the help page for hoods2d), the method is a SO-NF approach that first compares the observed binary field (obtained from the trheshold(s) provided by obj from hoods2dPrep), Ix, with the smoothed binary field, <Px>s. This smoothed binary field is thresholded by Pthresh to obtain a new binary field. The value of Pthresh that maximizes the verification score (provided by the which.score argument) is then used to compare Ix with <Iy>s, the binary forecast field obtained by thresholding the smoothed binary forecast field Iy using the value of Pthresh found above. The verification statistic determined by which.score is calculated between Ix and <Iy>s.
艾伯特（2008年）中描述的几乎完美的事后评估方法。使用类似的符号，其中描述（在帮助页面hoods2d），该方法是一个SO-NF的方法，比较观察到的二进制字段（（S）从obj所提供的trheshold hoods2dPrep），第九章，平滑的二进制字段的，<Px>。这平滑的二进制字段的阈值Pthresh，以获得一个新的二进制字段。核查最大化得分（设置由which.score参数）的值Pthresh然后用来比较Ix的与<Iy> s时，二进制预报场得到的阈值的平滑的二进制对预测字段IY的使用的值Pthresh发现以上。的核实统计由which.score的计算，之间Ix和<Iy>小号的。
值----------Value----------
A list object is returned with components:
返回一个List对象的组件：
参数：which.score
value of which.score, same as the argument passed in.
值的which.score，同样作为参数传入。
参数：Pthresh
l X q matrix giving the value of Pthresh applied at each level (rows) and threshold (columns).
升X q的矩阵给出Pthresh施加在每个水平（行）和阈值（列）的值。
参数：values
l X q matrix giving the value of which.score found for each level (rows) and threshold (columns).
长×q矩阵，每个级别（行）和阈值（列）的价值which.score。
警告----------Warning ----------
The value Pthresh is optimized under the assumption that larger values of which.score are better.
被优化的值Pthresh的假设条件下，较大的值which.score更好。
（作者）----------Author(s)----------
Eric Gilleland
参考文献----------References----------
forecasts: A review and proposed framework. Meteorol. Appl., 15, 51-64. DOI: 10.1002/met.25 Available at http://www.ecmwf.int/newsevents/meetings/workshops/2007/jwgv/METspecialissueemail.pdf
参见----------See Also----------
hoods2d, kernel2dsmooth, vxstats, hoods2dPlot, optim
hoods2d，kernel2dsmooth，vxstats，hoods2dPlot，optim
实例----------Examples----------
x <- y <- matrix( 0, 50, 50)
x[ sample(1:50,10), sample(1:50,10)] <- rexp( 100, 0.25)
y[ sample(1:50,20), sample(1:50,20)] <- rexp( 400)
hold <- hoods2dPrep("y", "x", thresholds=c(0.1, 0.5), levels=c(1, 3))
look <- pphindcast2d( hold)
look
## Not run: [＃不运行：]
data(geom001)
data(geom000)
data(ICPg240Locs)
hold <- hoods2dPrep( "geom001", "geom000", thresholds=c(0.01,50.01), levels=c(1, 3, 65), loc=ICPg240Locs, units="in/100")
look <- pphindcast2d( hold, verbose=TRUE)
par( mfrow=c(1,2))
hoods2dPlot( look$values, args=list( thresholds=hold$thresholds, units="in/100", levels=hold$levels), main="Gilbert Skill Score")
## 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。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-9-30 12:57:58
