我想使用随机森林建模来理解社区装配的变量重要性 - 我的响应数据是一个社区矩阵。
library(randomForestSRC)
# simulated species matrix
species
# site species 1 species2 species 3
# 1 1 1 0
# 2 1 0 1
# 3 1 1 1
# 4 1 0 1
# 5 1 0 0
# 6 1 1 0
# 7 1 1 0
# 8 1 0 0
# 9 1 0 0
# 10 1 1 0
# environmental data
data
# site elevation_m PRECIPITATION_mm
# 1 500 28
# 2 140 37
# 3 445 15
# 4 340 45
# 5 448 20
# 6 55 70
# 7 320 18
# 8 200 42
# 9 420 22
# 10 180 8
# adding my species matrix into the environmental data frame
data[["species"]] <-(species)
# running the model
rf_model <- rfsrc(Multivar(species) ~.,data = data, importance = T)
但我收到一条错误消息:
Error in parseFormula(formula, data, ytry) :
the y-outcome must be either real or a factor.
我猜这个问题是存在/不存在的数据,但我不确定如何超越它。这是功能的限制吗?
我认为这可能与您构建“数据”数据框架的方式有关。使用data[["species"]] <- (species)
时,数据框内有数据框。如果你在我刚才提到的步骤之后你str(data)
,输出是这样的:
> str(data)
'data.frame': 10 obs. of 4 variables:
$ site : int 1 2 3 4 5 6 7 8 9 10
$ elevation: num 500 140 445 340 448 55 320 200 420 180
$ precip : num 28 37 15 45 20 70 18 42 22 8
$ species :'data.frame': 10 obs. of 4 variables: #2nd data frame
..$ site : int 1 2 3 4 5 6 7 8 9 10
..$ species.1: num 1 1 1 1 1 1 1 1 1 1
..$ species2 : num 1 0 1 0 0 1 1 0 0 1
..$ species.3: num 0 1 1 1 0 0 0 0 0 0
如果您将数据框架构建为data2 <- as.data.frame(cbind(data,species))
,那么
rfsrc(Multivar(species.1,species2,species.3)~.,data = data2, importance=T)
似乎工作,因为我没有收到错误消息,而是我获得了一些合理的输出:
Sample size: 10
Number of trees: 1000
Forest terminal node size: 5
Average no. of terminal nodes: 2
No. of variables tried at each split: 2
Total no. of variables: 4
Total no. of responses: 3
User has requested response: species.1
Resampling used to grow trees: swr
Resample size used to grow trees: 10
Analysis: mRF-R
Family: regr+
Splitting rule: mv.mse *random*
Number of random split points: 10
% variance explained: NaN
Error rate: 0
我不认为你建立数据框架的方法是习惯的方式,但我可能是错的。我认为rfsrc()
不知道如何读取嵌套数据帧。我怀疑大多数建模功能没有额外的自定义代码。