[SOLVED] Approximate a Model by a given basic structures

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] Approximate a Model by a given basic structures

Postby Didier Renard » Sun Jul 03, 2016 3:32 pm

Here is my problem.

I have a model with a given basic structure (say a 1-D case with a triangle model) and I want to approximate it by a model composed of a set of given basic structures (which does not include the triangle structure).

How can I process?
Didier Renard
 
Posts: 337
Joined: Thu Sep 20, 2012 4:22 pm

Re: [SOLVED] Approximate a Model by a given basic structures

Postby Didier Renard » Sun Jul 03, 2016 3:40 pm

The idea is:
[*] to create the target model
[*] to create a fictitious variogram with the target structure (i.e. the triangle).
[*] to fit this experimental structure using the set of available basic structures.

The first step consists in creating the target model:
Code: Select all
model = model.create(vartype=19,ndim=1)


Then we create the fictitious variogram with the required structure, by discretizing the [0;2] interval by steps of 0.01 (i.e. 2001 lags):
Code: Select all
lag = 0.01
nlag = 201
vario = vario.create(lag,gg=model.eval(model,seq(1,nlag)*lag),sw=seq(nlag,1))


Finally we use the automatic fitting procedure to adjust a model on this experimental variogram using the set of required structures (sqy 2 K-Bessel structures):
Code: Select all
model.auto(vario,struct=c(8,8))

The last command can be repeated adding some constraints either on the total sill (using 'constraint' argument) or on each basic structure (using 'lower' or 'upper' argument)
Didier Renard
 
Posts: 337
Joined: Thu Sep 20, 2012 4:22 pm


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