GeoSimCopula {GeoModels} | R Documentation |
Simulation of Gaussian and non Gaussian Random Fields using copula.
Description
Simulation of Gaussian and some non Gaussian spatial, spatio-temporal and spatial bivariate random fields using Gaussian or Clayton copula. The function return a realization of a Random Field for a given covariance model and covariance parameters. Simulation is based on Cholesky decomposition.
Usage
GeoSimCopula(coordx, coordy=NULL, coordt=NULL,
coordx_dyn=NULL, corrmodel, distance="Eucl",
GPU=NULL, grid=FALSE, local=c(1,1),
method="cholesky", model='Gaussian', n=1, param,
anisopars=NULL,radius=6371, sparse=FALSE,
copula="Gaussian",seed=NULL, X=NULL,spobj=NULL,nrep=1)
Arguments
coordx |
A numeric ( |
coordy |
A numeric vector giving 1-dimension of
spatial coordinates; |
coordt |
A numeric vector giving 1-dimension of
temporal coordinates. Optional argument, the default is |
coordx_dyn |
A list of |
corrmodel |
String; the name of a correlation model, for the description see the Section Details. |
distance |
String; the name of the spatial distance. The default
is |
GPU |
Numeric; if |
grid |
Logical; if |
local |
Numeric; number of local work-items of the GPU |
method |
String; the type of matrix decomposition used in the simulation. Default is cholesky. The other possible choices is |
model |
String; the type of RF and therefore the densities associated to the likelihood
objects. |
n |
Numeric; the number of trials for binomial RFs. The number of successes in the negative Binomial RFs. Default is |
param |
A list of parameter values required in the simulation procedure of RFs, see Examples. |
anisopars |
A list of two elements "angle" and "ratio" i.e. the anisotropy angle and the anisotropy ratio, respectively. |
radius |
Numeric; a value indicating the radius of the sphere when using the great circle distance. Default value is the radius of the earth in Km (i.e. 6371) |
sparse |
Logical; if |
copula |
String; the type of copula. It can be "Clayton" or "Gaussian" |
seed |
Numeric; an integer used in set.seed function to reproduce the simulation. |
X |
Numeric; Matrix of space-time covariates. |
spobj |
An object of class sp or spacetime |
nrep |
Numeric; Numbers of indipendent replicates. |
Value
Returns an object of class GeoSimCopula
.
An object of class GeoSimCopula
is a list containing
at most the following components:
bivariate |
Logical: |
coordx |
A |
coordy |
A |
coordt |
A |
coordx_dyn |
A list of dynamical (in time) spatial coordinates; |
corrmodel |
The correlation model; see |
data |
The vector or matrix or array of data, see
|
distance |
The type of spatial distance; |
method |
The method of simulation |
model |
The type of RF, see |
n |
The number of trial for Binomial RFs;the number of successes in a negative Binomial RFs; |
numcoord |
The number of spatial coordinates; |
numtime |
The number the temporal realisations of the RF; |
param |
A list of the parameters |
radius |
The radius of the sphere if coordinates are passed in lon/lat format; |
randseed |
The seed used for the random simulation; |
spacetime |
|
copula |
The type of copula |
Author(s)
Moreno Bevilacqua, moreno.bevilacqua89@gmail.com,https://sites.google.com/view/moreno-bevilacqua/home, Víctor Morales Oñate, victor.morales@uv.cl, https://sites.google.com/site/moralesonatevictor/, Christian", Caamaño-Carrillo, chcaaman@ubiobio.cl,https://www.researchgate.net/profile/Christian-Caamano
Examples
library(GeoModels)
################################################################
###
### Example q. Simulation of a reparametrized Beta RF
### for beta regression
### with Gaussian and Clayton Copula
### with underlying Wendland correlation.
###
###############################################################
set.seed(261)
NN=1400
x <- runif(NN);y <- runif(NN)
coords=cbind(x,y)
shape1=3
shape2=3
smooth=0
corrmodel="GenWend"
min=0;max=1
X=cbind(rep(1,NN),runif(NN))
NuisParam("Beta2",num_betas=2,copula="Gaussian")
CorrParam("GenWend")
#### Gaussian copula
param=list(smooth=smooth,power2=4, min=min,max=max,
mean=0.1,mean1=0.1,scale=0.3,nugget=0,shape=5)
data <- GeoSimCopula(coordx=coords, corrmodel=corrmodel, model="Beta2",param=param,
copula="Gaussian",sparse=TRUE,X=X)$data
quilt.plot(coords,data)
#### Clayton copula
NuisParam("Beta2",num_betas=2,copula="Clayton")
CorrParam("GenWend")
param=list(smooth=smooth,power2=4, min=min,max=max,
mean=0.2,mean1=0.1,scale=0.3,nugget=0,shape=6,nu=4)
data1 <- GeoSimCopula(coordx=coords, corrmodel=corrmodel, model="Beta2",param=param,
copula="Clayton",sparse=TRUE,X=X)$data
hist(data1,freq=FALSE)
quilt.plot(coords,data1)