Displaying 2 results from an estimated 2 matches for "fz4".
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2009 Feb 03
3
non linear regression with nls
...water) starting from
the "Portata" variable (which is the water flow)
The functions that I'm using are:
> fz1<-function(Portata, a, b){a+b/Portata}
> fz2<-function(Portata, a, b){a*exp(b*Portata)}
> fz3<-function(Portata, a, b, d, e){a+b/Portata+d*(Portata^e)}
> fz4<-function(Portata, b, d){b*Portata^d}
> fz5<-function(Portata, a, b, d){a+b*(Portata^d)}
I've made a list of the functions with list(fz1, fz2, fz3, fz4, fz5)
and the starting , lower and upper parameters for each function are:
fz1: start=list(a=10, b=10), lower=list(a=0, b=0), upper=l...
2009 Feb 10
3
summary of a list
...ctions (formList), a list of starting
values (startList), uppervalues (upperList) and lower values (lowerList).
A sample of the list of function I use in the loop is the following:
FormList <- list(PTG.P ~ fz1(Portata, a, b), PTG.P ~ fz2(Portata, a, b), PTG.P ~ fz3(Portata,a, b, d, e),
PTG.P ~ fz4(Portata, a, b), PTG.P ~ fz5(Portata, a, b, d), PO4.P ~ fz1(Portata, a, b),
PO4.P ~ fz2(Portata, a, b), ...
And the loop I use is:
resultList <- list()
for (i in 1:length(formList))
{
resultList[[i]] <- nls(formList[[i]], data=subset(dati, Fiume=="Laveggio"), start=startList[[i]...