coef.pdMat {nlme} | R Documentation |

## pdMat Object Coefficients

### Description

This method function extracts the coefficients associated with the
positive-definite matrix represented by `object`

.

### Usage

## S3 method for class 'pdMat':
coef(object, unconstrained, ...)
## S3 method for class 'pdMat':
coef(object, ...) <- value

### Arguments

`object` |
an object inheriting from class `pdMat` ,
representing a positive-definite matrix. |

`unconstrained` |
a logical value. If `TRUE` the coefficients
are returned in unconstrained form (the same used in the optimization
algorithm). If `FALSE` the upper triangular elements of the
positive-definite matrix represented by `object` are
returned. Defaults to `TRUE` . |

`value` |
a vector with the replacement values for the coefficients
associated with `object` . It must be a vector with the same length
of `coef{object}` and must be given in unconstrained form. |

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

### Value

a vector with the coefficients corresponding to `object`

.

### SIDE EFFECTS

On the left side of an assignment, sets the values of the coefficients
of `object`

to `value`

.

### Author(s)

Jose Pinheiro and Douglas Bates

### References

Pinheiro, J.C. and Bates., D.M. (1996) "Unconstrained Parametrizations
for Variance-Covariance Matrices", Statistics and Computing, 6, 289-296.

### See Also

`pdMat`

### Examples

coef(pdSymm(diag(3)))

[Package

*nlme* version 3.1-66

Index]