pdConstruct.pdBlocked {nlme} | R Documentation |

This function give an alternative constructor for the `pdBlocked`

class, representing a positive-definite block-diagonal matrix. Each
block-diagonal element of the underlying matrix is itself a
positive-definite matrix and is represented internally as an
individual `pdMat`

object. When `value`

is
`numeric(0)`

, a list of uninitialized `pdMat`

objects, a
list of one-sided formulas, or a list of vectors of character strings,
`object`

is returned as an uninitialized `pdBlocked`

object
(with just some of its attributes and its class defined) and needs to
have its coefficients assigned later, generally using the `coef`

or `matrix`

replacement functions. If `value`

is a list of initialized
`pdMat`

objects, `object`

will be constructed from the list
obtained by applying `as.matrix`

to each of the `pdMat`

elements of `value`

. Finally, if `value`

is a list of
numeric vectors, they are assumed to represent the unrestricted
coefficients of the block-diagonal elements of the underlying
positive-definite matrix.

## S3 method for class 'pdBlocked': pdConstruct(object, value, form, nam, data, pdClass, ...)

`object` |
an object inheriting from class `pdBlocked` ,
representing a positive definite block-diagonal matrix. |

`value` |
an optional list with elements to be used as the
`value` argument to other `pdMat` constructors. These
include: `pdMat` objects, positive-definite
matrices, one-sided linear formulas, vectors of character strings, or
numeric vectors. All elements in the list must be similar (e.g. all
one-sided formulas, or all numeric vectors). Defaults to
`numeric(0)` , corresponding to an uninitialized object. |

`form` |
an optional list of one-sided linear formula specifying the
row/column names for the block-diagonal elements of the matrix
represented by `object` . Because factors may be present in
`form` , the formulas needs to be evaluated on a data.frame to
resolve the names they defines. This argument is ignored when
`value` is a list of one-sided formulas. Defaults to `NULL` . |

`nam` |
an optional list of vector of character strings specifying the
row/column names for the block-diagonal elements of the matrix
represented by object. Each of its components must have
length equal to the dimension of the corresponding block-diagonal
element and unreplicated elements. This argument is ignored when
`value` is a list of vector of character strings. Defaults to
`NULL` . |

`data` |
an optional data frame in which to evaluate the variables
named in `value` and `form` . It is used to
obtain the levels for `factors` , which affect the
dimensions and the row/column names of the underlying matrix. If
`NULL` , no attempt is made to obtain information on
`factors` appearing in the formulas. Defaults to the
parent frame from which the function was called. |

`pdClass` |
an optional vector of character strings naming the
`pdMat` classes to be assigned to the individual blocks in the
underlying matrix. If a single class is specified, it is used for all
block-diagonal elements. This argument will only be used when
`value` is missing, or its elements are not `pdMat`
objects. Defaults to `"pdSymm"` . |

`...` |
some methods for this generic require additional arguments. None are used in this method. |

a `pdBlocked`

object representing a positive-definite
block-diagonal matrix, also inheriting from class `pdMat`

.

Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu

`as.matrix.pdMat`

, `coef.pdMat`

,
`matrix<-.pdMat`

pd1 <- pdBlocked(list(c("A","B"), c("a1", "a2", "a3"))) pdConstruct(pd1, list(diag(1:2), diag(c(0.1, 0.2, 0.3))))

[Package *nlme* version 3.1-57 Index]