simspde {RGeostats}R Documentation

Perform Simulations using SPDE technology

Description

Perform Simulations using SPDE technology

Usage

simspde(dbin = NA, dbout, model = NA, pattern = NA, triswitch = "nqQ",
        nostat = NA, seed = 232131, nbsimu = 1, numparts=NA, ngiter=10,
        nburn = 50,niter = 100,
        gext = NA, flag.gibbs = FALSE, flag.grid = TRUE,
        flag.modif = FALSE, verbose = FALSE,
        radix = "SPDE", modify.target = db.locmod())

Arguments

dbin

The db-class structure containing the input 2-D data. This file is optional: when absent, we perform non-conditional simulations; when present, we perform conditional simulations. When used, there must be a single variable defined.

dbout

The db-class structure which contains the resulting simulations.

model

The model-class describing the spatial characteristics.

pattern

When 'dbout' is organized as regular grid, the simulation may take place starting from the definition of a pattern.

triswitch

Command line for the internal triangulation step. For more information see meshing.

nostat

List of non-stationary parameters. For details see model.param.define.

seed

Seed for the random number generation.

nbsimu

Number of simulations.

numparts

Array for subdividing the field into parts. Its dimension must be equal to the space dimension. If not defined (or equal to 1 in each space direction), the space is not subdivided. Subdividing in parts reduces the dimension of the matrices and can be used in the case of large files (input or output). In order to reduce the artifacts that may be induced by the subdivision, two steps of subdivisions are actually processed. For illustration purpose, let us assume that the field (SX by SY) with origin (X0,Y0) is subdivided into NX ny NY parts.

  • Step 1: The field is subdivided into NX by NY parts, with dimensions equal to SX/NX and SY/NY

  • Step 2: The field (with origin X0-SX/2, Y0-SY/2) is subdivided into NX+1 by NY+1 parts, with dimensions equal to SX/NX and SY/NY.

ngiter

When the field is subdivided into several parts, several iterations are necessary to glue the parts. This parameter defined the number of iterations to be processed.

nburn

Number of burning iterations when the iterative Gibbs method is used as a simulation procedure. During these burning simulations, the intervals are gradually restrained from almost no constraint down to the final constraints.

niter

Number of iterations when the iterative Gibbs method is used as a simulation procedure.

gext

When 'dbout' is organized as a grid, it may be dilated by gext. This argument designates an array, with its dimension equal to the dimension of the space and which contains the extension defined in number of grid nodes.

flag.gibbs

When TRUE, the iterative Gibbs method is used.

flag.grid

When FALSE, the simulation is performed after a triangulations step. This is NOT the default solution when performing non-conditional simulation(s) on a 'dbout' organized as a grid.

flag.modif

When TRUE, the simulation outcomes are not stored individually. Instead the simulations outcomes are summarized in two output variables, i.e. the mean and standard deviation of dispersion of the simulations.

verbose

Verbose option

radix

Radix of the name given to the variables storing the results in the target Db.

modify.target

Decides whether or not the newly created variables will have their locator defined or not. For more information, see db.locmod.

Value

The output db-class where the following variables have been added:

The Double Quilting can be switched OFF by using the function set.keypair() with the keyword "Flag_Double_Quilt". By default, its value is set to 1.

The keypair mechanism has also been used to transmit the some values calculated internally to the user with the keywords:


[Package RGeostats version 11.0.6 Index]