# corBlomberg

From ape v2.6-3
by Emmanuel Paradis

##### Blomberg et al.'s Correlation Structure

The ``ACDC'' (accelerated/decelerated) model assumes that continuous traits evolve under a Brownian motion model which rates accelerates (if $g$ < 1) or decelerates (if $g$ > 1) through time. If $g$ = 1, then the model reduces to a Brownian motion model.

- Keywords
- models

##### Usage

```
corBlomberg(value, phy, form = ~1, fixed = FALSE)
## S3 method for class 'corBlomberg':
corMatrix(object, covariate = getCovariate(object),
corr = TRUE, ...)
## S3 method for class 'corBlomberg':
coef(object, unconstrained = TRUE, \dots)
```

##### Arguments

- value
- the (initial) value of the parameter $g$.
- phy
- an object of class
`"phylo"`

. - form
- (ignored).
- fixed
- a logical specifying whether
`gls`

should estimate $\gamma$ (the default) or keep it fixed. - object
- an (initialized) object of class
`"corBlomberg"`

. - covariate
- (ignored).
- corr
- a logical value specifying whether to return the correlation matrix (the default) or the variance-covariance matrix.
- unconstrained
- a logical value. If
`TRUE`

(the default), the coefficients are returned in unconstrained form (the same used in the optimization algorithm). If`FALSE`

the coefficients are returned in ``natural'', possibly constrained, f - ...
- further arguments passed to or from other methods.

##### Value

- an object of class
`"corBlomberg"`

, the coefficients from an object of this class, or the correlation matrix of an initialized object of this class. In most situations, only`corBlomberg`

will be called by the user.

##### References

Blomberg, S. P., Garland, Jr, T., and Ives, A. R. (2003) Testing for
phylogenetic signal in comparative data: behavioral traits are more
labile. *Evolution*, **57**, 717--745.

*Documentation reproduced from package ape, version 2.6-3, License: GPL (>= 2)*

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