#
# EPage 374
#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

save_plots = F

library(DAAG)
library(rpart)

set.seed(0)

if( save_plots ){ postscript("../../WriteUp/Graphics/Chapter11/prob_3_plot.eps", onefile=FALSE, horizontal=FALSE) }

# Overfit our tree model and then prune: 
m = rpart( re78 ~ ., data=nswpsid1, method="anova", cp=0.002 )
plotcp(m)

if( save_plots ){ dev.off() }

cp_opt = 0.5 * ( 0.022 + 0.01 ) 
m = prune( m, cp=cp_opt )
plotcp(m)

# Print the final tree: 
if( save_plots ){ postscript("../../WriteUp/Graphics/Chapter11/prob_3_final_tree_plot.eps", onefile=FALSE, horizontal=FALSE) }
plot(m); text(m)
if( save_plots ){ dev.off() }