pfortier wrote:Thanks! I looked at those documents many times and used v("range") many times but never noticed examples using the following
Well, 4.4 Range variables
Hines, M.L. and Carnevale, N.T.
The NEURON simulation environment.
Neural Computation 9:1179-1209, 1997
does mention diameter and gnabar_hh, but the Programmer's Reference really needs an easily findable, explicit statement about range variables (if I knew of one, I'd have pointed you to it, or more likely you would already have found it).
Range variables allow algorithmic assignment of diameter and biophysical properties as functions of position, e.g.
soma for (x,0) gnabar_hh(x) = 0.1*x
forall for (x,0) gbar_kd(x) = p(x) // p is a function of the segment center's xyz coordinates
Note the "for (x,0)" syntax. What are the gnabar_hh values that result from the first statement? What would they be if the statement were
soma for (x) gnabar_hh(x) = 0.1*x // a common error
An aside: this thread illustrates three key points.
1. Human language is imprecise. You thought the meaning of your original question was perfectly clear. I had a very different understanding of it, and only grasped your meaning after a brief exchange.
2. Sometimes the "right" (i.e. formally correct) answer to a question is the wrong answer, because the question itself is the wrong question.
3. A real conversation provides many opportunities for detecting and correcting both of these problems. Such corrections are harder to achieve in the course of brief text exchanges e.g. via email, fora, etc..