nnwhich(spatstat)
nnwhich()所属R语言包：spatstat
Nearest neighbour
最近的邻居
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Finds the nearest neighbour of each point in a point pattern.
找到最近的邻居的每一个点在一个点模式。
用法----------Usage----------
nnwhich(X, ...)
## S3 method for class 'ppp'
nnwhich(X, ..., k=1, method="C")
## Default S3 method:
nnwhich(X, Y=NULL, ..., k=1, method="C")
参数----------Arguments----------
参数：X,Y
Arguments specifying the locations of a set of points. For nnwhich.ppp, the argument X should be a point pattern (object of class "ppp"). For nnwhich.default, typically X and Y would be numeric vectors of equal length. Alternatively Y may be omitted and X may be a list with two components x and y, or a matrix with two columns.
指定的位置的一组点的引数。 nnwhich.ppp，参数X应该是一个点模式（类的对象"ppp"“）。对于nnwhich.default，通常X和Y将数字向量的长度相等。或者Y可以省略，并且X可以是带有两个组件的列表x和y，或一个具有两列的矩阵。
参数：...
Ignored by nnwhich.ppp and nnwhich.default.
忽略nnwhich.ppp和nnwhich.default。
参数：k
Integer, or integer vector. The algorithm will compute the distance to the kth nearest neighbour.
整数或整数向量。该算法计算距离的的k日最近的邻居。
参数：method
String specifying which method of calculation to use. Values are "C" and "interpreted".
字符串，用于指定使用的计算方法。值是"C"和"interpreted"。
Details
详细信息----------Details----------
For each point in the given point pattern, this function finds its nearest neighbour (the nearest other point of the pattern). By default it returns a vector giving, for each point, the index of the point's nearest neighbour. If k is specified, the algorithm finds each point's kth nearest neighbour.
如果在给定的点图案中的每个点，此函数发现其近邻（最接近的其他点的图案）。默认情况下，它返回一个向量的付出，每一个点，该指数点的近邻。如果k指定的算法发现各点的k日最近的邻居。
The function nnwhich is generic, with method for point patterns (objects of class "ppp") and a default method which are described here, as well as a method for three-dimensional point patterns (objects of class "pp3", described in nnwhich.pp3.
的功能nnwhich是通用的，与点图案的方法（对象类"ppp"）和一个默认的方法，该方法描述在这里，以及作为三维点图案的方法（类的对象的 "pp3"，在nnwhich.pp3。
The method nnwhich.ppp expects a single point pattern argument X. The default method expects that X and Y will determine the coordinates of a set of points. Typically X and Y would be numeric vectors of equal length. Alternatively Y may be omitted and X may be a list with two components named x and y, or a matrix or data frame with two columns.
的方法nnwhich.ppp预计单点模式的话，X。默认的方法，希望这X和Y将确定一组点的坐标。通常情况下X和Y将数字向量的长度相等。或者Y可以省略，并且X可能是一个名为x和y，或具有两列的矩阵或数据框的两个组件列表。
The argument k may be a single integer, or an integer vector. If it is a vector, then the kth nearest neighbour distances are computed for each value of k specified in the vector.
参数k可能是一个整数或整数向量。如果它是一个向量，然后k个近邻距离k向量中指定的每个值的计算。
If there are no points (if x has length zero) a numeric vector of length zero is returned. If there is only one point (if x has length 1), then the nearest neighbour is undefined, and a value of NA is returned. In general if the number of points is less than or equal to k, then a vector of NA's is returned.
如果没有点（如果x长度为零的）返回长度为零的一个数值向量。如果只有一个点（如果x具有长度为1），那么最近的邻居是未定义的，和一个值NA返回。一般来说，如果点的数量小于或等于k，然后一个向量的NAs的返回。
The argument method is not normally used. It is retained only for checking the validity of the software. If method = "interpreted" then the distances are computed using interpreted R code only. If method="C" (the default) then C code is used. The C code is faster by two to three orders of magnitude and uses much less memory.
参数method不能正常使用。它只会保留检查的软件的有效性。如果method = "interpreted"的距离计算仅使用解释R代码。如果method="C"（默认值），那么C代码使用。 C代码由两到三个数量级，速度更快，占用更少的内存。
To evaluate the distance between a point and its nearest neighbour, use nndist.
为了评估一个点之间的距离和离它最近的邻居，使用nndist。
To find the nearest neighbours from one point pattern to another point pattern, use nncross.
要找到最近的邻居模式从一个点到另一个点的模式，使用nncross。
值----------Value----------
Numeric vector or matrix giving, for each point, the index of its nearest neighbour (or kth nearest neighbour).
数字向量或矩阵，每一个点，给其最近的邻居（或k日最近的邻居）的索引。
If k = 1 (the default), the return value is a numeric vector v giving the indices of the nearest neighbours (the nearest neighbout of the ith point is the jth point where j = v[i]).
如果k = 1（默认值），则返回值是一个数值向量v给近邻指数（最近neighbout i个点是j个点j = v[i]“）。
If k is a single integer, then the return value is a numeric vector giving the indices of the kth nearest neighbours.
如果k是一个整数，则返回值是一个数值向量k日最近的邻居给的指标。
If k is a vector, then the return value is a matrix m such that m[i,j] is the index of the k[j]th nearest neighbour for the ith data point.
如果k是一个向量，则返回值是一个矩阵mm[i,j]是该指数的k[j]日最近的邻居i日数据点。
警告----------Warnings----------
A value of NA is returned if there is only one point in the point pattern.
返回值NA如果只有一个点的点模式。
（作者）----------Author(s)----------
Pavel Grabarnik
<a href="mailto:pavel.grabar@issp.serpukhov.su">pavel.grabar@issp.serpukhov.su</a>
and
Adrian Baddeley
<a href="mailto:Adrian.Baddeley@csiro.au">Adrian.Baddeley@csiro.au</a>
<a href="http://www.maths.uwa.edu.au/~adrian/">http://www.maths.uwa.edu.au/~adrian/</a>
参见----------See Also----------
nndist, nncross
nndist，nncross
实例----------Examples----------
data(cells)
plot(cells)
m <- nnwhich(cells)
m2 <- nnwhich(cells, k=2)
# plot nearest neighbour links[绘制最近的邻居链接]
b <- cells[m]
arrows(cells$x, cells$y, b$x, b$y, angle=15, length=0.15, col="red")
# find points which are the neighbour of their neighbour[这是他们的邻居的邻居找点]
self <- (m[m] == seq(m))
# plot them[绘制出来]
A <- cells[self]
B <- cells[m[self]]
plot(cells)
segments(A$x, A$y, B$x, B$y)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
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 13:50:52
