Hi, R-folks:
I have been tryin many combination of parameter to make Matern variogram to
work, but I can't find the available one. I'm near to be crazy.
I tiped:
Año2003Selg.lf<-likfit(Año2003Selg,cov.model="matern",ini.cov.pars=c(1.5,14),kappa=2.5,fix.kappa=FALSE,nugget=0.08,lambda=0.008,fix.lambda=FALSE,hessian=TRUE)
the hessian shows:
$hessian
[,1] [,2] [,3] [,4]
[1,] 9.139986 -8.562736e+00 41.648355 -3.801615
[2,] -8.562736 3.351952e+159 -147.279881 -7.083089
[3,] 41.648355 -1.472799e+02 347.493191 -7.509035
[4,] -3.801615 -7.083089e+00 -7.509035 90.681917
Then, I put: solve(Año2003Selg.lf$info.minimisation.function$hessian)
...and it's shown as following:
Error in solve.default(Año2003Selg.lf$info.minimisation.function$hessian) :
sistem is computationally singular: number of reciprocity condition=
1.05091e-159
on account of I work in Spanish, it's shown:
Error in solve.default(Año2003Selg.lf$info.minimisation.function$hessian) :
sistema es computacionalmente singular: número de condición recíproco =
1.05091e-159
I also wander if there is any limit for kappa. Which one would be the maximun.
As far as I'm concerned, it must be always major than cero, right?. I also know
that its values depend on the tendency of cloud semivariogram, if it flattens
slowly (Gaussian) it's major.
I'll thank the one available to answer my desperate question.
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