nls error regarding numerics vs logicals
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