[R] nls error regarding numerics vs logicals

[Duncan Murdoch]

On 09/07/2010 1:51 PM, Jim Bouldin wrote:
> I am trying to perform an nls for a valid negative exponential function:
>
> zz=nls(y~constant+a.est*2.7183^(b.est*x),start=list(constant=4.0,a.est=-4,b.est
> = -.005),trace=T)
>
> and am getting a number of different error messages, the most problematic
> of  which is "Error in nls(ring.area ~ constant + a.est * 2.7183^(b.est *
> ba.beg), start = list(constant = 4,  : 
>   REAL() can only be applied to a 'numeric', not a 'logical'"
>
> I can't see where there are any "logicals" in this equation to cause this
> problem.  Any help appreciated. Thank you.

1.  The expression you gave us is clearly not the one that produced the 
error:  it involved "ring.area" and "ba.beg".

2.  You don't tell us what x and y are, so we can't reproduce anything.

We can't help you if you don't tell us what the problem is.

Duncan Murdoch