# mkReTrms

##### Make Random Effect Terms: Create Z, Lambda, Lind, etc.

From the result of `findbars`

applied to a model formula
and the evaluation frame `fr`

, create the model matrix
`Zt`

, etc, associated with the random-effects terms.

- Keywords
- utilities

##### Usage

```
mkReTrms(bars, fr, drop.unused.levels=TRUE,
reorder.terms=TRUE,
reorder.vars=FALSE)
```

##### Arguments

- bars
a list of parsed random-effects terms

- fr
a model frame in which to evaluate these terms

- drop.unused.levels
(logical) drop unused factor levels? (experimental)

- reorder.terms
arrange random effects terms in decreasing order of number of groups (factor levels)?

- reorder.vars
arrange columns of individual random effects terms in alphabetical order?

##### Value

a `list`

with components

transpose of the sparse model matrix for the random effects

initial values of the covariance parameters

an integer vector of indices determining the mapping of
the elements of the `theta`

vector to the `"x"`

slot of
`Lambdat`

a vector indexing the association of
elements of the conditional mode vector
with random-effect terms; if `nb`

is the vector of numbers
of conditional modes per term (i.e. number of groups times number
of effects per group), `Gp`

is `c(0,cumsum(nb))`

(and conversely `nb`

is `diff(Gp)`

)

lower bounds on the covariance parameters

transpose of the sparse relative covariance factor

list of grouping factors used in the random-effects terms

a list of column names of the random effects according to the grouping factors

list of components of the transpose of the random-effects model matrix, separated by random-effects term

##### See Also

Other utilities: `findbars`

,
`mkRespMod`

, `nlformula`

,
`nobars`

, `subbars`

.
`getME`

can retrieve these components
from a fitted model, although their values and/or forms
may be slightly different in the final fitted model from
their original values as returned from `mkReTrms`

.

##### Examples

```
# NOT RUN {
data("Pixel", package="nlme")
mform <- pixel ~ day + I(day^2) + (day | Dog) + (1 | Side/Dog)
(bar.f <- findbars(mform)) # list with 3 terms
mf <- model.frame(subbars(mform),data=Pixel)
rt <- mkReTrms(bar.f,mf)
names(rt)
# }
```

*Documentation reproduced from package lme4, version 1.1-21, License: GPL (>= 2)*