Displaying 2 results from an estimated 2 matches for "ssexample".
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asexample
2009 Sep 21
1
How to use nls when [selfStart] function returns NA or Inf??
...value or an infinity produced when evaluating the model
or (if I provide a gradient attribute)
Error in qr.default(.swts * attr(rhs, "gradient")) :
NA/NaN/Inf in foreign function call (arg 1)
A toy example demonstrating my problem (legal values of param are >1):
#-----------
SSexample<-selfStart(
model=function(x, param) x^log(param-1),
initial = function(mCall, data, LHS){
val<- 1.001
names(val) <- mCall[c("param")]
val
},
parameters=c("param")
)
#----------------
nls(y~SSexample(x, par), data=data.frame(x=1:10,y=rnorm(10)))
#--------...
2009 Sep 04
1
How should a SelfStart function handle illegal parameter values?
Hi Everyone,
I'm trying to write selfStart non-linear models for use with nls. In these
models some combinations of parameter values are illegal; the function value
is undefined.
That's OK when calling the function directly [e.g. SSmodel(x, pars...)]; I
return an appropriate non-value such as NA or Inf.
However, when called from nls [e.g. nls(y~SSmodel(x, pars...), ...)] those