问题
could someone explain to me why these two pieces of codes return two diferent things? the first one :
x<-y<-seq(from=-1,to=1,by=0.1)
one<-function(x,y){
x
}
z<-outer(x,y,FUN=one)
persp(x,y,z)
returns the surface it should.
while :
x<-y<-seq(from=-1,to=1,by=0.1)
one<-function(x,y){
array(1, dim=length(x))
}
z<-outer(x,y,FUN=one)
persp(x,y,z)
returns : "Error in persp.default(x, y, z = outer(x, y, one)) : invalid 'z' limits"
回答1:
For the second case, plotting the plane z=1, you just need to specify the desired zlim yourself, e.g.
persp(x,y,z,zlim=c(0,2))
The persp function expects to plot in a 3-dimensional space. The default is to try to plot over the ranges of x, y and z, but in this case z's range is degenerate.
来源：https://stackoverflow.com/questions/32054123/r-outer-function-error-in-persp-defaultx-y-z-invalid-z-limits