if (requireNamespace("KernSmooth")) {##'
ksmooth2(rmvn0(1e4,sigma=diag(2)*.5+.5),c(-3.5,3.5),h=1,
        rgl=FALSE,theta=30)
##'
if (interactive()) {
    ksmooth2(rmvn0(1e4,sigma=diag(2)*.5+.5),c(-3.5,3.5),h=1)
    ksmooth2(function(x,y) x^2+y^2, c(-20,20))
    ksmooth2(function(x,y) x^2+y^2, xlim=c(-5,5), ylim=c(0,10))
    f <- function(x,y) 1-sqrt(x^2+y^2)
    surface(f,xlim=c(-1,1),alpha=0.9,aspect=c(1,1,0.75))
    surface(f,xlim=c(-1,1),clut=heat.colors(128))
    ##play3d(spin3d(axis=c(0,0,1), rpm=8), duration=5)
}
if (interactive()) {
    surface(function(x) dmvn0(x,sigma=diag(2)),c(-3,3),lit=FALSE,smooth=FALSE,box=FALSE,alpha=0.8)
    surface(function(x) dmvn0(x,sigma=diag(2)),c(-3,3),box=FALSE,specular="black")##'
}
if (!inherits(try(find.package("fields"),silent=TRUE),"try-error")) {
    f <- function(x,y) 1-sqrt(x^2+y^2)
    ksmooth2(f,c(-1,1),rgl=FALSE,image=fields::image.plot)
}
}
Run the code above in your browser using DataLab