inla.mesh.segment {INLA} | R Documentation

## Constraint segments for inla.mesh

### Description

Constructs `inla.mesh.segment` objects that can be used to specify boundary and interior constraint edges in calls to `inla.mesh`.

### Usage

    ## Create or join inla.mesh.segment objects.
    inla.mesh.segment(...)
    ## Default S3 method:
    inla.mesh.segment(loc = NULL, idx = NULL, grp = NULL,
      is.bnd = TRUE, crs = NULL, ...)
    ## S3 method for class 'inla.mesh.segment'
    inla.mesh.segment(..., grp.default = 0)

    inla.contour.segment(x = seq(0, 1, length.out = nrow(z)),
                         y = seq(0, 1, length.out = ncol(z)),
                         z,
                         nlevels = 10,
                         levels = pretty(range(z, na.rm = TRUE), nlevels),
                         groups = seq_len(length(levels)),
                         positive = TRUE,
                         eps = NULL,
                         crs = NULL)

### Arguments

`loc` | Matrix of point locations.
`idx` | Segment index sequence vector or index pair matrix. The indices refer to the rows of `loc`. If `loc==NULL`, the indices will be interpreted as indices into the point specification supplied to `inla.mesh.create`. If `is.bnd==TRUE`, defaults to linking all the points in `loc`, as `c(1:nrow(loc),1L)`, otherwise `1:nrow(loc)`.
`grp` | Vector of group labels for each segment. Set to `NULL` to let the labels be chosen automatically in a call to `inla.mesh.create`.
`is.bnd` | `TRUE` if the segments are boundary segments, otherwise `FALSE`.
`grp.default` | When joining segments, use this group label for segments that have `grp=NULL`.
`x, y, z, nlevels, levels` | Parameters specifying a set of surface contours, with syntax described in `contour`.
`groups` | Vector of group ID:s, one for each contour level.
`positive` | `TRUE` if the contours should encircle positive level excursions in a counter clockwise direction.
`eps` | Tolerance for `inla.simplify.curve`.
`crs` | An optional `CRS` or `inla.CRS` object
`...` | Additional parameters. When joining segments, a list of `inla.mesh.segment` objects.

### Value

An `inla.mesh.segment` object.

### Author(s)

Finn Lindgren finn.lindgren@gmail.com

### See Also

`inla.mesh.create`, `inla.mesh.2d`

### Examples

    ## Create a square boundary and a diagonal interior segment
    loc.bnd = matrix(c(0,0, 1,0, 1,1, 0,1), 4, 2, byrow=TRUE)
    loc.int = matrix(c(0.9,0.1, 0.1,0.6), 2, 2, byrow=TRUE)
    segm.bnd = inla.mesh.segment(loc.bnd)
    segm.int = inla.mesh.segment(loc.int, is.bnd=FALSE)

    ## Points to be meshed
    loc = matrix(runif(10*2),10,2)*0.9+0.05
    mesh = inla.mesh.create(loc,
                            boundary=segm.bnd,
                            interior=segm.int,
                            refine=list())
    plot(mesh)

    ## Not run:
    mesh = inla.mesh.create(loc, interior=list(segm.bnd, segm.int))
    plot(mesh)

    ## End(Not run)

[Package INLA version 18.07.12 Index]