# Chapter 13: Manipulation of density estimates. Code

## The order of going through rectangles

We illustrate algorithm LeafsFirst in
the case of calculating a level set tree.

N<-c(16,16)
pcf<-sim.data(N=N,type="mulmod")
lst<-leafsfirst(pcf)
leafsfirst.visu(lst,pcf,lkmbound=28)

Next we illustrate algorithm LeafsFirst in
the case of calculating a shape tree.

st<-leafsfirst(pcf,propor=0.1)
leafsfirst.visu(st,pcf,propor=0.1,lkmbound=28)

## Dynamic illustration

We illustrate algorithm LeafsFirst
in the case of calculating a shape tree.
Function ``plottwin'' makes 2 windows.
The first window shows a level set and the second
window shows the shape tree, with the vector representation.
Click with the mouse at the second window to let the algorithm proceed.

N<-c(8,8) # size of the grid
pcf<-sim.data(N=N,type="fox") # piecewise constant function
lev<-0.002 # level of the level set
refe<-c(0,0) # reference point
st<-leafsfirst(pcf,lev,refe) # shape tree
plottwin(st,pcf,lev,refe)

We used a level set of the
fox density
and we applied a very sparse grid to approximate the function.