Displaying 1 result from an estimated 1 matches for "avrogadro".
Did you mean:
avogadro
2011 Jun 30
1
Error "singular gradient matrix at initial parameter estimates" in nls
...nt start values. If anyone
finds some time to have a look at that, any advice would be very much
appreciated.
##Brice-Model
bricemod<-nls(log10(D) ~ log10(Do)*exp(((-4*pi*En*Na)*((ro/2)*(r-ro)^2
+(1/3)*(r-ro)^3))/(R*T)), start=list(Do=0.8, En=390,
ro=1.03),trace=TRUE)
Na<-6.0221415*10^23 # Avrogadro's number
T<-1010 # Temp in K
R<-8.3144 #Gas constant [J mol^-1 K^-1]
r<-data.matrix(PRr[c("r")])
r
La 1.160
Ce 1.143
Pr 1.109
Nd 1.093
Sm1.079
Eu 1.066
Gd 1.053
Tb 1.040
Dy 1.027
Ho 1.015
Er 1.004
Tm 0.994
Yb 0.985
Lu 0.977
D<-data.matrix(PRr[c("D...