[R] Bug with curve?

[Alberto Monteiro]

Paul Smith wrote:
> 
>> f <- function(x) exp(-x)*x-0.05
>> g <- function(x) 0
>> curve(f,0,5)
>> curve(g,add=T)
>> Error in xy.coords(x, y) : 'x' and 'y' lengths differ
>>
> 
> However, with
> 
> g <- function(x) x-x
> 
> no error is generated.
> 
> Is this a bug? 
>
No; simplify it:

g1 <- function(x) 0
g2 <- function(x) x - x

g1(anything) will return (scalar) 0

g2(scalar) will return (scalar) 0, g2(vector) will return 
(vector) 0, g2(matrix) will return (matrix) 0.

So, in your original problem, f and (first) g have different
behaviours. 

Alberto Monteiro