tripack (version 1.0-1)

outer.convhull: Version of outer which operates only in a convex hull

Description

This version of outer evaluates FUN only on that part of the grid $cx x cy$ that is enclosed within the convex hull of the points (px,py). This can be useful for spatial estimation if no extrapolation is wanted.

Usage

outer.convhull(cx,cy,px,py,FUN,duplicate="remove",...)

Arguments

cx

x cordinates of grid

cy

y cordinates of grid

px

vector of x coordinates of points

py

vector of y coordinates of points

FUN

function to be evaluated over the grid

duplicate

indicates what to do with duplicate $(px_i,py_i)$ points, default "remove".

Value

• Matrix with values of FUN (NAs if outside the convex hull).

See Also

in.convex.hull

Examples

x<-runif(20)
y<-runif(20)
z<-runif(20)
z.lm<-lm(z~x+y)
f.pred<-function(x,y)
  {predict(z.lm,data.frame(x=as.vector(x),y=as.vector(y)))$predictor}
xg<-seq(0,1,0.05)
yg<-seq(0,1,0.05)
image(xg,yg,outer.convhull(xg,yg,x,y,f.pred))
points(x,y)

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