[SOLVED] Problem with the bounds in model.auto function

Here you can report the problems encountered when using a function relative to the variography:
- experimental variography (vario.calc, vario.grid, vmap.calc, ...)
- model fitting (model.auto)

[SOLVED] Problem with the bounds in model.auto function

Postby Nicolas Desassis » Mon Sep 16, 2013 5:07 pm

It seems that the upper options is without effect (and it is the same for the lower one) on this example.
I would like to limit the sill of the nugget at 1.

data(Exdemo_autofit1.model)
vario <- model.sample(Exdemo_autofit1.model,lag=0.1,nlag=100)
model.auto(vario,upper=c(1,NA,NA,NA,NA,NA),flag.noreduce=T,verbose=T)

Am I doing something wrong?
Nicolas Desassis
 
Posts: 198
Joined: Thu Sep 20, 2012 4:22 pm

Re: Problem with the bounds in model.auto function

Postby Didier Renard » Mon Sep 16, 2013 7:19 pm

Dear Nicolas

This is the answer to your question.
If you run a first try of model.auto using the argument verbose=T (as you did) but without bothering about specifying bounds, you will immediately see that the number of parameters to be fitted are 9:
1) sill of the nugget effect
2 & 3) range and sill of the gaussian
4 & 5) range and sill of the cubic
6 & 7) range and sill of the exponential
8 & 9) range and sill of the spherical

Now let's come to the upper or lower arguments. The module is expecting a COMPLETE vector of bounds. If the dimension of the lower or upper vector is not equal to 9, the input arguments are ignored (without message).
Instead, using an input vector as follows:

upper = c(1,NA,NA,NA,NA,NA,NA,NA,NA)

will produce the following printout (with verbose option ON):

Model
-----
Structure : Nugget Effect
1 - Sill : 0.860091 [0.000000,1.000000]
Structure : Gaussian
2 - Sill : 0.339909 [0.000000,NA[
3 - Range U : 0.001070 [0.000010,NA[
Structure : Cubic
4 - Sill : -0.000000 [0.000000,NA[
5 - Range U : 4.526838 [0.000010,NA[
Structure : Exponential
6 - Sill : 0.000000 [0.000000,NA[
7 - Range U : 6.048644 [0.000010,NA[
Structure : Spherical
8 - Sill : 2.400000 [0.000000,NA[
9 - Range U : 5.200000 [0.000010,NA[

We clearly see that the upper bound of the sill of the nugget effect has been taken into account correctly.
Didier Renard
 
Posts: 337
Joined: Thu Sep 20, 2012 4:22 pm

Re: Problem with the bounds in model.auto function

Postby Nicolas Desassis » Wed Sep 18, 2013 9:04 am

:( You were right...
Nicolas Desassis
 
Posts: 198
Joined: Thu Sep 20, 2012 4:22 pm


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