I am trying to simulate a neuron model where the gating variables are subject to noise. Now I know that I can simply add noise to one of those gating variables by adding xi to the equation. But if I try to add this term to multiple gating variables I get the error “The equation defining m contains the symbol “xi”, but it is already used in the equation defining n.” It is not immediately obvious what I should use instead and the documentation hasn’t been much help for me so far. Has anyone here some experience with this?
Thanks in advance!
Hi. I had another look at the documentation and realized that we do not explain this at all… The reason why we do not allow to have
xi in two equations is that it becomes ambiguous whether the two symbols should refer to the same noise variable (i.e. use the same instantiation of the noise) or whether the two should be independent. We therefore require you to use
xi_... with an arbitrary suffix – these variables will interpreted in the same way as a simple
xi. If you repeat the same name, it will be the same noise. If you use different names, it will be independent noise.
So in your case, you can use e.g.
xi_m to make clear that the two noise sources are independent.
Thanks a lot! I didn’t know about the suffixes, that solves it!