R help - Feb 2006 - Passing additional paramaters to nlsList(nlme) fit function

Hello, nls-users,

is it possible to pass additional parameters to the model function that are
known and groupwise constant with nlsList? I could not find something like a
"keep this fixed" option in the documentation and the code (my
fault...?)

The current workaround is to break the problem down into groups and use
globals to pass the constant parameters, but it is ugly code and won't work
when an over-all nlme is needed.

Dieter Menne

The "nlsList" function does NOT have the common ellipsis
("..." )
argument to support that.

	  An alternative is use "vector" to create an object of mode
"list" of
the desired length, then in a loop call "nls" (which does support
"...")
and store the results in a list.  However, this won't produce an object 
of class "nlsList", which means that the methods writted for
"nlsList"
will not be available to you.

	  If it were my problem, I might make a local copy of the "nlsList" 
function and try to modify it to work, at least for my problem.  In this 
case, "nlsList" is merely a call to "UseMethods".  To get
beyond that, I
requested 'methods("nlsList")' with the following result:

	  nlsList.formula    nlsList.selfStart*

	  If you supply your own starting values, you don't need 
"nlsList.selfStart".  If you do need it, you can get it via 
'getAnywhere("nlsList.selfStart")';  the asterisk
("*") says that this
function is "non-visible", which means that just typing its name
won't
get it.  Then I might use "debug" to figure out what it's doing
and what
I want to change.

	  hope this helps.
	  spencer graves

Dieter Menne wrote:
> Hello, nls-users,
> 
> is it possible to pass additional parameters to the model function that are
> known and groupwise constant with nlsList? I could not find something like
a
> "keep this fixed" option in the documentation and the code (my
fault...?)
> 
> The current workaround is to break the problem down into groups and use
> globals to pass the constant parameters, but it is ugly code and won't
work
> when an over-all nlme is needed.
> 
> Dieter Menne
> 
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