Displaying 2 results from an estimated 2 matches for "fz3".
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2009 Feb 03
3
non linear regression with nls
...variable (PTG, PO4, NT, ..., which are concentration of substances in 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 fu...
2009 Feb 10
3
summary of a list
...ession curves using a list of functions (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=="Lav...