R: Names of implemented covariance and variogram models

RFgetModelNames {RandomFields} | R Documentation

## Names of implemented covariance and variogram models

### Description

Displays the names of covariance and variogram models (see `RMmodel`) and returns them as a list. The user may specify and group the models according to the following properties:

- type of function (`"positive definite"`, `"variogram"`, etc.)

- whether the function depends on two arguments (`"kernel"`) or on one argument only (`"single variable"`)

- types of isotropy

- whether the model is an operator

- whether the model is a normal scale mixture

- whether the model has a finite range covariance

- validity in certain dimensions of the coordinate space

- maximal possible dimension of the coordinate space

- uni- or multivariety

See `Details` for an explanation and `RMmodelgenerator` for possible states (values) of these properties.

### Usage

    RFgetModelNames(type = RC_TYPENAMES, domain = RC_DOMAIN_NAMES,
                    isotropy = RC_ISONAMES, operator = c(TRUE, FALSE),
                    monotone = RC_MONOTONE_NAMES,
                    implied_monotonicities = length(monotone) == 1,
                    finiterange = c(TRUE, FALSE, NA),
                    valid.in.dim = c(1, Inf),
                    vdim = c(1, 5),
                    group.by,
                    simpleArguments = FALSE,
                    internal, newnames)

### Arguments

`type, domain, isotropy, operator, monotone, finiterange, vdim` | see constants for the definition of `RC_TYPENAMES`, `RC_DOMAIN_NAMES`, etc. See also `RMmodelgenerator`.
`implied_monotonicities` | logical. If `TRUE` then all the models with a stronger monotonocity than the required one are also shown.
`valid.in.dim` | an optional integer indicating the dimension of the space where the model is valid
`group.by` | an optional character string or `NULL`; must be one of `'type'`, `'domain'`, `'isotropy'`, `'operator'`, `'monotone'`, `'finiterange'`,`'maxdim'`,`'vdim'`. If `group.by` is not given, the result is grouped by `'type'` if more than one type is given.
`simpleArguments` | logical. if `TRUE`, only models are considered whose arguments are all integer or real valued.
`internal, newnames` | both logical; `internal` might be also integer valued. If any of them are given, `RFgetModelNames` behaves very differently. See the Notes below.

### Details

The plain call `RFgetModelNames()` simply gives back a vector of the names of all implemented covariance and variogram models and operators, i.e. members of the class `RMmodelgenerator`.

The following arguments can be specified. In general, only exact matches are returned. One exception exists: If the length of `type` equals 1 and if `group.by` is not given, then types included in `type` are also returned. E.g. if `type="variogram"` and `group.by` is not given then only models are returned that are negative definite. Howeveralso positive definite functions and tail correlaton functions are returned if `"type"` is included in `group.by`.

`type`

  specifies the class of functions; for the meaning of the possible values see `RMmodelgenerator`

`stationarity`

  specifies the type of stationarity; for the meaning of the possible values see `RMmodelgenerator`

`isotropy`

  specifies the type of isotropy; for the meaning of the possible values see `RMmodelgenerator`

`operator`

  indicates whether the model is an operator, i.e. it requires at least one submodel, e.g. `+` or `RMdelay` are operators; see `RMmodelgenerator`

`monotone`

  indicates what kind of monotonicity is known, e.g., whether the model is a normal scale mixture, the latter including `RMexp` or `RMcauchy`; see `RMmodelgenerator`

`finiterange`

  indicates whether the covariance of the model has finite range, e.g. `RMcircular` or `RMnugget` have covariances with finite range; see `RMmodelgenerator`. `NA` is used if the finiteness depends on the submodel,

`valid.in.dim`

  If `valid.in.dim=n` is passed, all models which are valid in dimension n are displayed. Otherwise `valid.in.dim` should be bivariate vector giving the range of requested dimensions.

`maxdim`

  if a positive integer, it specifies the maximal possible dimension of the coordinate space; note that a model which is valid in dimension n is also valid in dimension n-1; `maxdim=-1` means that the maximal possible dimension depends on the parameters of the `RMmodel` object; `vdim=-2` means that the maximal possible dimension is adopted from the called submodels; see also `RMmodelgenerator`

`vdim`

  if a positive integer, vdim specifies, whether the model is vdim-variate; `vdim=-1` means that being multivariate in a certain dimension depends on the parameters of the `RMmodel` object; `vdim=-2` means that being multivariate in a certain dimension is adopted from the called submodels; see also `RMmodelgenerator`

  If `vdim` is bivariate then a range is given.

`group.by`

  If `group.by="propertyname"` is passed, the displayed models are grouped according to `propertyname`.

All arguments allow also for vectors of values. In case of `valid.in.dim` the smallest value is taken. The interpretation is canonical.

Note that the arguments `stationarity`, `isotropy`, `operator`, `monotone`, `finiterange`, `maxdim`, `vdim` are also slots (attributes) of the SP4-class `RMmodelgenerator`.

### Value

Either a vector of model names if the argument `group.by` is not used; or a list of vectors of model names if the argument `group.by` is used (with list elements specified by the categories of the grouping argument).

In case `internal` or `newnames` is given, `RFgetModelNames` prints a table of the currently implemented covariance functions and the matching methods. `RFgetModelNames` returns `NULL`.

### Note

In case `internal` or `newnames` is given, only the values of `internal`, `newnames` and `operator` are considered. All the other arguments are ignored and `RFgetModelNames` prints a table of the currently implemented covariance functions and the matching methods:

- `internal`:
  if `TRUE` also `RMmodels` are listed that are internal, hence invisible to the user. Default: `FALSE`.

- `newnames`:
  The model names of version 2 of RandomFields and earlier can still be used in the model definitions. Namely when the list notation is chosen; see Advanced RMmodels for the latter. If the `internal` or `newnames` is given, then these old names are shown; if `newnames=TRUE` then also the usual names are shown. Default: `FALSE`.

  In fact, both internal and public models can have different variants implemented. These variants are also shown if `internal` has a value greater than or equal to`2`,

- `operator`:
  see above.

Here, also an indication is given, which method for simulating Gaussian random fields matches the model.

### Author(s)

Martin Schlather, schlather@math.uni-mannheim.de http://ms.math.uni-mannheim.de/de/publications/software

### See Also

constants, `RMmodelgenerator`, `RMmodel`, `RandomFields`, RC_DOMAIN_NAMES, RC_ISONAMES

### Examples

    RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
    ##                   RFoptions(seed=NA) to make them all random again

    # get list of names of all functions
    RFgetModelNames()

    # any kind of positive definite functions
    RFgetModelNames(type="positive definite")

    # get a list of names of all stationary models
    RFgetModelNames(type="positive definite", domain="single variable")

    # get a vector of all model names
    RFgetModelNames(group.by=NULL)

[Package RandomFields version 3.1.50 Index]