在pdp :: partial图上添加概率边界

问题描述

我有一个二进制分类问题的预测概率图。我有两个问题：

如何为p = 0.5绘制单个概率中断？使用contour = TRUE自变量会添加几行。
是否可以添加另一个预测变量来绘制3D图？

这就是我现在拥有的：

代表：


require(caret)
train.ctrl <- trainControl(method = "repeatedcv",number = 10,repeats = 5,summaryFunction = twoClassSummary,classprobs = TRUE,)

set.seed(1337)
lr.fit <- train(Class ~ .,data = train.small,trControl = train.ctrl,method = "glm",family = "binomial",metric = "ROC",preProcess = c("center","scale")
                 )

require(pdp)
lr.pd <- partial(lr.fit,pred.var = c("x1","x2"),prob = TRUE,plot = TRUE,chull = FALSE,grid.resolution = 20,progress = "text",plot.engine = "ggplot"     
                #,levelplot = TRUE
                #,contour = TRUE
                )
lr.pd

# dataset used: 
> dput(train.small)

structure(list(x1 = c(-2.27966818800131,-0.338448010439568,-0.205849502281457,0.845604758116324,0.237243699016471,1.24653636015188,0.141150345247212,-1.94634378874626,0.844265652370458,-0.364520848772231,-1.23724847469945,1.38848801851204,-1.36106463689431,-0.563757474548103,-1.06688494837985,1.95249141033933,-0.19013864138727,-0.582286822918036,-0.121851924837777,0.708635458099694,0.232606893541271,-0.973242157622908,-0.839124499580887,-1.60414910952904,-2.48941991263215,-0.307956293709429,1.47833943928667,0.878621754086077,-0.98322797566842,-1.07796826066294
),x2 = c(-2.52279563738851,-1.75938416652951,1.39754416931398,-0.00212755901980971,1.08662786676201,-0.515199741525909,0.467733663414545,-0.466317884258174,-0.836744523943926,-0.718136687911924,-1.73906216686269,1.59934935188848,-1.27639037325246,-0.32993091478973,-2.05445383777137,-0.0189083922948782,-0.818464313993987,-1.15168959538223,1.99668352214088,0.671670710096937,0.680397233698906,0.267937956913229,-1.78107607016152,-1.53728406964112,-1.05660014431803,-0.316921861836086,2.65603302304451,0.885179019517534,-0.220384928450498,-1.94445363537753),Class = c("No","Yes","No","Yes")),row.names = c(24L,2L,10L,9L,26L,22L,12L,11L,21L,17L,7L,19L,27L,8L,25L,16L,5L,18L,29L,6L,14L,15L,13L,20L,1L,30L,4L,23L,28L,3L),class = "data.frame")

解决方法

以下是您对问题号的回答。 1.
您可以使用以下简单代码在p = 0.5处绘制轮廓线：

lr.pd + geom_contour(color = "white",breaks=0.5,size=1)

ggplot2 r r