distconnected(vegan)
distconnected()所属R语言包：vegan
Connectedness of Dissimilarities
连通性四不像
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Function distconnected finds groups that are connected disregarding dissimilarities that are at or above a threshold or NA. The function can be used to find groups that can be ordinated together or transformed by stepacross. Function no.shared returns a logical dissimilarity object, where TRUE means that sites have no species in common. This is a minimal structure for distconnected or can be used to set missing values to dissimilarities.
函数distconnected发现无视异同，处于或高于一个阈值或NA连接的基团。可以使用的功能找到可以协调在一起或由stepacross转化的基团。功能no.shared返回一个逻辑相异对象的，其中TRUE是指该网站有没有共同的物种。 distconnected或可以用来设置缺失值相异，这是最小的结构。
用法----------Usage----------
distconnected(dis, toolong = 1, trace = TRUE)
no.shared(x)
参数----------Arguments----------
参数：dis
Dissimilarity data inheriting from class dist or a an object, such as a matrix, that can be converted to a dissimilarity matrix. Functions vegdist and dist are some functions producing suitable dissimilarity data.
相异数据从类继承dist或一个对象，如为一个矩阵，可以转换到一个相异矩阵。功能vegdist和dist是合适的相异数据的一些功能。
参数：toolong
Shortest dissimilarity regarded as NA. The function uses a fuzz factor, so that dissimilarities close to the limit will be made NA, too. If toolong = 0 (or negative), no dissimilarity is regarded as too long.
最短相异视为NA。该函数使用一个模糊的因素，所以，接近极限的异同，将NA，太。如果toolong = 0（或负），没有相异看作太长。
参数：trace
Summarize results of distconnected
总结distconnected
参数：x
Community data.
社区数据。
Details
详细信息----------Details----------
Data sets are disconnected if they have sample plots or groups of sample plots which share no species with other sites or groups of sites. Such data sets cannot be sensibly ordinated by any unconstrained method because these subsets cannot be related to each other. For instance, correspondence analysis will polarize these subsets with eigenvalue 1. Neither can such dissimilarities be transformed with stepacross, because there is no path between all points, and result will contain NAs. Function distconnected will find such subsets in dissimilarity matrices. The function will return a grouping vector that can be used for sub-setting the data. If data are connected, the result vector will be all 1s. The connectedness between two points can be defined either by a threshold toolong or using input dissimilarities with NAs.
数据集是断开的，如果他们有样地或团体，没有种的样地分享网站与其他网站或团体。这样的数据集不能明智地协调通过任何无约束方法，因为这些不能相互关联的子集。例如，对应分析极化子集的特征值1。也不能这样的异同转化stepacross，因为没有所有的点之间的路径，结果将包含NA的。函数distconnected会发现这样的子集相异矩阵。该函数将返回一组向量，可用于子设置的数据。如果数据连接，结果向量将所有的“1的。在两个点之间的连通性可以被定义的阈值toolong或输入相异NA的的使用。
Function no.shared returns a dist structure having value TRUE when two sites have nothing in common, and value FALSE when they have at least one shared species. This is a minimal structure that can be analysed with distconnected. The function can be used to select dissimilarities with no shared species in indices which do not have a fixed upper limit.
功能no.shared返回一个dist结构的价值TRUE时，两个网站没有任何共同之处，和值FALSE时，他们至少有一个共享的物种。这是一个很小的结构，可以分析distconnected。该函数可以被用来选择与指数不具有一个固定的上限没有共享的物种的异同。
Function distconnected uses depth-first search (Sedgewick 1990).
函数distconnected使用深度优先搜索（Sedgewick 1990年）。
值----------Value----------
Function distconnected returns a vector for observations using integers to identify connected groups. If the data are connected, values will be all 1. Function no.shared returns an object of class dist.
功能distconnected返回一个向量，观测使用整数来识别连接的组。连接，如果数据的值将是所有1。功能no.shared返回一个对象类dist。
（作者）----------Author(s)----------
Jari Oksanen
参考文献----------References----------
参见----------See Also----------
vegdist or dist for getting dissimilarities, stepacross for a case where you may need distconnected, and for connecting points spantree.
vegdist或dist为获得不同点，stepacross的情况下，您可能需要的distconnected，和连接点spantree。
实例----------Examples----------
## There are no disconnected data in vegan, and the following uses an[＃有没有断开连接的数据素食主义者，和下面使用]
## extremely low threshold limit for connectedness. This is for[＃极低的阈值限制连通。这是为]
## illustration only, and not a recommended practice.[＃（仅供参考），而不是一个推荐的做法。]
data(dune)
dis <- vegdist(dune)
gr <- distconnected(dis, toolong=0.4)
# Make sites with no shared species as NA in Manhattan dissimilarities[使网站没有共享种NA在曼哈顿的异同]
dis <- vegdist(dune, "manhattan")
is.na(dis) <- no.shared(dune)
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。
|
发表于 2012-10-1 15:05:42
