#
# 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.
# 
#-----

stem <- function(x,y,pch=16,linecol=1,clinecol=1,...){
if (missing(y)){
    y = x
    x = 1:length(x) }
    plot(x,y,pch=pch,...)
    for (i in 1:length(x)){
       lines(c(x[i],x[i]), c(0,y[i]),col=linecol)
    }
    lines(c(x[1]-2,x[length(x)]+2), c(0,0),col=clinecol)
}

N=41

z_r_k = c( 0.88, 0.83, 0.72, 0.67, 0.56, 0.53, 0.43, 0.41, 0.32, 0.29, 0.21, 0.18 )
zd_r_k = c( -0.83, 0.68, -0.70, -0.65, 0.62, -0.70, 0.69, -0.60, 0.55, -0.60, 0.62 )

z4d_r_k = c( 0.21, 0.06, 0.15, -0.34, -0.10, 0.03, -0.18, -0.13, 0.02, -0.04, 0.10, 0.22 )
zd4d_r_k = c( -0.33, 0.06, 0.36, -0.45, 0.08, 0.22, -0.10, -0.05, 0.14, -0.12, -0.05, 0.28 )

#postscript("../../WriteUp/Graphics/Chapter9/prob_6_zrk_plot.eps", onefile=FALSE, horizontal=FALSE)
stem( z_r_k, pch=18 )
abline(h=+2/sqrt(N),col="red")
abline(h=-2/sqrt(N),col="red")
#dev.off()

#postscript("../../WriteUp/Graphics/Chapter9/prob_6_zdrk_plot.eps", onefile=FALSE, horizontal=FALSE)
stem( zd_r_k, pch=18 )
abline(h=+2/sqrt(N-1),col="red")
abline(h=-2/sqrt(N-1),col="red")
#dev.off()
 
#postscript("../../WriteUp/Graphics/Chapter9/prob_6_z4drk_plot.eps", onefile=FALSE, horizontal=FALSE)
stem( z4d_r_k, pch=18 )
abline(h=+2/sqrt(N-4),col="red")
abline(h=-2/sqrt(N-4),col="red")
#dev.off()

#postscript("../../WriteUp/Graphics/Chapter9/prob_6_zd4drk_plot.eps", onefile=FALSE, horizontal=FALSE)
stem( zd4d_r_k, pch=18 )
abline(h=+2/sqrt(N-5),col="red")
abline(h=-2/sqrt(N-5),col="red")
#dev.off()