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. Jim Bouldin
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
> 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.Sorry, I guess that was unclear. I changed the response and independent variable names to y and x respectively, in hopes that would be clearer. Both are numeric variables. Jim