[R] Puzzled on nlm

[Laura Holt]

Dear R People:

Here is a function to minimized:
>mfun1
function(x,a) {
  x[1] <- a[1]*x[2] + a[3] - a[2]*(a[1]-a[2])*a[3]
  x[2] <- a[1]*x[1] - a[2]*a[3]
  return(x)
}

Here is my first try:
>nlm(mfun1,c(1,1))
Error in f(x, ...) : Argument "a" is missing, with no default
>

>nlm(mfun1,c(1,1),a=c(0.8,0.5,1))
Error in nlm(mfun1, c(1, 1), a = c(0.8, 0.5, 1)) :
        invalid function value in 'nlm' optimizer
>

I am stumped.  I'm sure that it's something really small that I'm 
overlooking.

Thanks in advance for any help.

Sincerely,
Laura Holt
mailto: lauraholt_983 at hotmail.com