simper(vegan)
simper()所属R语言包：vegan
Similarity Percentages
相似度百分比
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Discriminating species between two groups using Bray-Curtis dissimilarities
布雷柯蒂斯相异的两个组之间的鉴别物种
用法----------Usage----------
simper(comm, group, ...)
## S3 method for class 'simper'
summary(object, ordered = TRUE,
digits = max(3, getOption("digits") - 3), ...)
参数----------Arguments----------
参数：comm
Community data matrix.
社区数据矩阵。
参数：group
Factor describing the group structure. Must have at least 2 levels.
描述组结构的因素。必须至少有2个级别。
参数：object
an object returned by simper.
返回的对象simper。
参数：ordered
Logical; Should the species be ordered by their average contribution?
逻辑的品种，责令其平均贡献？
参数：digits
Number of digits in output.
输出中的数字位数。
参数：...
Parameters passed to other functions.
参数传递给其他函数。
Details
详细信息----------Details----------
Similarity percentage, simper (Clarke 1993) is based on the decomposition of Bray-Curtis dissimilarity index (see vegdist, designdist). The contribution of individual species i to the overall Bray-Curtis dissimilarity d[jk] is given by
相似的比例，simper（克拉克1993年）的基础上布雷柯蒂斯相异指数的分解（见vegdist，designdist）。的贡献，个别品种i的整体布雷柯蒂斯相异d[jk]的给出了
where x is the abundance of species i in sampling units j and k. The overall index is the sum of the individual contributions over all S species d[jk] = sum(i=1..S) d[ijk].
其中x是物种丰富度i抽样单位j和k。综合指数是所有的S种d[jk] = sum(i=1..S) d[ijk]的个人的贡献的总和。
The simper functions performs pairwise comparisons of groups of sampling units and finds the average contributions of each species to the average overall Bray-Curtis dissimilarity.
simper功能的一组抽样单位进行两两比较，发现平均每个物种的整体平均布雷柯蒂斯相异的贡献。
The function displays most important species for each pair of groups. These species contribute at least to 70 % of the differences between groups. The function returns much more extensive results which can be accessed directly from the result object (see section Value). Function summary transforms the result to a list of data frames. With argument ordered = TRUE the data frames also include the cumulative contributions and are ordered by species contribution.
功能显示最重要的物种每对groups。这些物种的至少70％的组间差异。该函数返回更广泛的结果，可以直接访问结果对象（见价值部分）。函数summary转换到一个列表中的数据框的结果。参数ordered = TRUE的数据框还包括累计捐款是按物种的贡献。
The results of simper can be very difficult to interpret. The method very badly confounds the mean between group differences and within group variation, and seems to single out variable species instead of distinctive species (Warton et al. 2012). Even if you make groups that are copies of each other, the method will single out species with high contribution, but these are not contributions to non-existing between-group differences but to within-group variation in species abundance.
simper是非常困难的解释。方法非常严重混淆组之间的差异和组内变异，平均和似乎挑出易变的种类，而不是独特物种（沃顿等人，2012）。即使你组的相互拷贝，该方法将挑出种与高贡献，但这些都不是不存在组间差异，但组内变异物种丰度的贡献。
值----------Value----------
A list of class "simper" with following items:
列表类"simper"以下项目的：
参数：species
The species names.
该品种名称。
参数：average
Average contribution to overall dissimilarity.
平均整体相异的贡献。
参数：overall
The overall between-group dissimilarity.
整体组间的差异性。
参数：sd
Standard deviation of contribution.
标准偏差的贡献。
参数：ratio
Average to sd ratio.
平均到SD的比例。
参数：ava, avb
Average abundances per group.
每个组的平均丰度。
参数：ord
An index vector to order vectors by their contribution or order cusum back to the original data order.
索引向量订购向量所作出的贡献或命令cusum返回到原来的数据顺序。
参数：cusum
Ordered cumulative contribution.
有序累计贡献。
（作者）----------Author(s)----------
Eduard Sz枚cs <a href="mailto:szoe8822@uni-landau.de">szoe8822@uni-landau.de</a>
参考文献----------References----------
in community structure. Australian Journal of Ecology, 18, 117鈥 |
发表于 2012-10-1 15:13:05
