Thse functions are deprecated. Please see `sar`

for the new
syntax. These functions are constructors for the `cor_sar`

class
implementing spatial simultaneous autoregressive structures.
The `lagsar`

structure implements SAR of the response values:
$$y = \rho W y + \eta + e$$
The `errorsar`

structure implements SAR of the residuals:
$$y = \eta + u, u = \rho W u + e$$
In the above equations, \(\eta\) is the predictor term and
\(e\) are independent normally or t-distributed residuals.

```
cor_sar(W, type = c("lag", "error"))
cor_lagsar(W)
cor_errorsar(W)
```

## Arguments

- W
An object specifying the spatial weighting matrix.
Can be either the spatial weight matrix itself or an
object of class `listw`

or `nb`

, from which
the spatial weighting matrix can be computed.

- type
Type of the SAR structure. Either `"lag"`

(for SAR of the response values) or `"error"`

(for SAR of the residuals).

## Value

An object of class `cor_sar`

to be used in calls to

`brm`

.

## Details

Currently, only families `gaussian`

and `student`

support SAR structures.

## Examples

```
if (FALSE) {
data(oldcol, package = "spdep")
fit1 <- brm(CRIME ~ INC + HOVAL, data = COL.OLD,
autocor = cor_lagsar(COL.nb),
chains = 2, cores = 2)
summary(fit1)
plot(fit1)
fit2 <- brm(CRIME ~ INC + HOVAL, data = COL.OLD,
autocor = cor_errorsar(COL.nb),
chains = 2, cores = 2)
summary(fit2)
plot(fit2)
}
```