[R] Please, help me with 'mattern' variogram

[David Cross]

I think the problem is with the (2,2) element in your hessian, unless  
that is a typo.

Cheers

David Cross
d.cross at tcu.edu
www.davidcross.us




On Nov 16, 2010, at 8:33 PM, Jimmy Martina wrote:

>
> 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. 		 	    
> 		  <ATT00001..txt>