LongCART (version 3.2)

plot: Plot an SurvCART or LongCART Object

Description

Plots an SurvCART or LongCART object on the current graphics device.

Usage

# S3 method for SurvCART
plot(x, uniform = FALSE, branch = 1, compress = FALSE, 
              nspace = branch, margin = 0, minbranch = 0.3, ...)
# S3 method for LongCART
plot(x, uniform = FALSE, branch = 1, compress = FALSE, 
              nspace = branch, margin = 0, minbranch = 0.3, ...)

Arguments

x

a fitted object of class "SurvCART", containing a survival tree or "LongCART", containing a longitudinal tree.

uniform

similar to plot.rpart; if TRUE, uniform vertical spacing of the nodes is used; this may be less cluttered when fitting a large plot onto a page. The default is to use a non-uniform spacing proportional to the error in the fit.

branch

similar to plot.rpart; controls the shape of the branches from parent to child node. Any number from 0 to 1 is allowed. A value of 1 gives square shouldered branches, a value of 0 give V shaped branches, with other values being intermediate.

compress

similar to plot.rpart; if FALSE, the leaf nodes will be at the horizontal plot coordinates of 1:nleaves. If TRUE, the routine attempts a more compact arrangement of the tree.

nspace

similar to plot.rpart; the amount of extra space between a node with children and a leaf, as compared to the minimal space between leaves. Applies to compressed trees only. The default is the value of branch.

margin

similar to plot.rpart; an extra fraction of white space to leave around the borders of the tree. (Long labels sometimes get cut off by the default computation).

minbranch

similar to plot.rpart; set the minimum length for a branch to minbranch times the average branch length. This parameter is ignored if uniform=TRUE. Sometimes a split will give very little improvement, or even (in the classification case) no improvement at all. A tree with branch lengths strictly proportional to improvement leaves no room to squeeze in node labels.

...

arguments to be passed to or from other methods.

Value

The coordinates of the nodes are returned as a list, with components x and y.

Details

This function is a method for the generic function plot, for objects of class SurvCART. The y-coordinate of the top node of the tree will always be 1.

References

Kundu, M. G., and Harezlak, J. (2019). Regression trees for longitudinal data with baseline covariates. Biostatistics & Epidemiology, 3(1):1-22.

Kundu, M. G., and Ghosh, S. (2021). Survival trees based on heterogeneity in time-to-event and censoring distributions using parameter instability test. Statistical Analysis and Data Mining: The ASA Data Science Journal, 14(5), 466-483.

See Also

text, SurvCART, LongCART

Examples

# NOT RUN {
#--- Get the data
data(GBSG2)

#numeric coding of character variables
GBSG2$horTh1<- as.numeric(GBSG2$horTh)
GBSG2$tgrade1<- as.numeric(GBSG2$tgrade)
GBSG2$menostat1<- as.numeric(GBSG2$menostat)

#Add subject id
GBSG2$subjid<- 1:nrow(GBSG2)

#--- Run SurvCART()
out<- SurvCART(data=GBSG2, patid="subjid", censorvar="cens", timevar="time", event.ind=1, 
        gvars=c('horTh1', 'age', 'menostat1', 'tsize', 'tgrade1', 'pnodes', 'progrec', 'estrec'),  
        tgvars=c(0,1,0,1,0,1, 1,1),          
        alpha=0.05, minsplit=80,  
        minbucket=40, print=TRUE)

#--- Plot tree
par(xpd = TRUE)
plot(out, compress = TRUE)
text(out, use.n = TRUE)
# }