UGgmm-class {qpgraph} | R Documentation

## Undirected Gaussian graphical Markov model

### Description

The `"UGgmm"` class is the class of undirected Gaussian graphical Markov models defined within the `qpgraph` package to store simulate and manipulate this type of graphical Markov models (GMMs).

An undirected Gaussian GMM is a family of multivariate normal distributions sharing a set of conditional independences encoded by means of an undirected graph. Further details can be found in the book of Lauritzen (1996).

### Objects from the Class

Objects can be created by calls of the form `UGgmm(g, ...)` corresponding to constructor methods or `rUGgmm(n, g, ...)` corresponding to random simulation methods.

### Slots

`p`:

  Object of class `"integer"` storing the dimension of the undirected Gaussian GMM corresponding to the number of random variables.

`g`:

  Object of class `graphBAM-class` storing the associated undirected labeled graph.

`mean`:

  Object of class `"numeric"` storing the mean vector.

`sigma`:

  Object of class `dspMatrix-class` storing the covariance matrix.

### Methods

`UGgmm(g)`

  Constructor method where `g` can be either an adjacency matrix or a `graphBAM-class` object.

`rUGgmm(n, g)`

  Constructor simulation method that allows one to simulate undirected Gaussian GMMs where `n` is the number of GMMs to simulate and `g` can be either a graphParam object, an adjacency matrix or a `graphBAM-class` object.

`names(x)`

  Accessor method to obtain the names of the elements in the object `x` that can be retrieved with the `$` accessor operator.

`$`

  Accessor operator to retrieve elements of the object in an analogous way to a `list`.

`dim(x)`

  Dimension of the undirected Gaussian GMM corresponding to the total number of random variables.

`dimnames(x)`

  Names of the random variables in the undirected Gaussian GMM.

`show(object)`

  Method to display some bits of information about the input undirected Gaussian GMM specified in `object`.

`summary(object)`

  Method to display a sumamry of the main features of the input undirected Gaussian GMM specified in `object`.

`plot(x, ...)`

  Method to plot the undirected graph associated to the the input undirected Gaussian GMM specified in `x`. It uses the plotting capabilities from the `Rgraphviz` library to which further arguments specified in `...` are further passed.

### Author(s)

R. Castelo

### References

Lauritzen, S.L. Graphical models. Oxford University Press, 1996.

### See Also

HMgmm

[Package qpgraph version 2.21.2 Index]