R help - Apr 2004 - outer

Hello,

Can anyone help explain why the following are not
equivalent?

I have written a function called cord.mag(x,y) which
takes two numbers and outputs a number.

Further I defined m=1:5, n=1:26
>  for(i in m) { for (j in n) print(cord.mag(i,j))}
this prints the m*n values, one on each line properly
> outer(m,n,cord.mag)
this gives me a matrix of zeroes
> outer(1,2,cord.mag)
this gives the right value on the other hand

Thanks

K Fung <fungile at yahoo.com> writes:
> > outer(m,n,cord.mag)
> 
> this gives me a matrix of zeroes
> 
> > outer(1,2,cord.mag)
> 
> this gives the right value on the other hand
Your cord.mag function probably doesn't vectorize. Try

Cord.mag <- function(m,n) mapply(cord.mag, m, n)
outer(m, n, Cord.mag)

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
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