Constructs observation/prediction weight matrices
for rSPDE models based on `inla.mesh`

or
`inla.mesh.1d`

objects.

## Usage

```
rspde.make.A(
mesh = NULL,
loc = NULL,
A = NULL,
dim = NULL,
rspde_order = 2,
nu = NULL,
index = NULL,
group = NULL,
repl = 1L,
n.group = NULL,
n.repl = NULL
)
```

## Arguments

- mesh
An

`inla.mesh`

, an`inla.mesh.1d`

object or a`metric_graph`

object.- loc
Locations, needed if an INLA mesh is provided

- A
The A matrix from the standard SPDE approach, such as the matrix returned by

`inla.spde.make.A`

. Should only be provided if`mesh`

is not provided.- dim
the dimension. Should only be provided if an

`mesh`

is not provided.- rspde_order
The order of the covariance-based rational SPDE approach.

- nu
If

`NULL`

, then the model will assume that nu will be estimated. If nu is fixed, you should provide the value of nu.- index
For each observation/prediction value, an index into loc. Default is

`seq_len(nrow(A.loc))`

.- group
For each observation/prediction value, an index into the group model.

- repl
For each observation/prediction value, the replicate index.

- n.group
The size of the group model.

- n.repl
The total number of replicates.

## Examples

```
#devel version
if (requireNamespace("INLA", quietly = TRUE)){
library(INLA)
set.seed(123)
loc <- matrix(runif(100 * 2) * 100, 100, 2)
mesh <- inla.mesh.2d(
loc = loc,
cutoff = 50,
max.edge = c(50, 500)
)
A <- rspde.make.A(mesh, loc = loc, rspde_order = 3)
}
#devel.tag
```