neighbors

Class: TriRep

(Will be removed) Simplex neighbor information

 Note:   `neighbors(TriRep)` will be removed in a future release. Use `neighbors(triangulation)` instead.`TriRep` will be removed in a future release. Use `triangulation` instead.

Syntax

`SN = neighbors(TR, SI)`

Description

`SN = neighbors(TR, SI)` returns the simplex neighbor information for the specified simplices `SI`.

Input Arguments

 `TR` Triangulation representation. `SI` `SI` is a column vector of simplex indices that index into the triangulation matrix `TR.Triangulation`. If `SI` is not specified the neighbor information for the entire triangulation is returned, where the neighbors associated with simplex `i` are defined by the `i`'th row of `SN`.

Output Arguments

 `SN` `SN` is an `m`-by-`n` matrix, where `m = length(SI)` , the number of specified simplices, and `n` is the number of neighbors per simplex. Each row `SN(i,:)` represents the neighbors of the simplex `SI(i)`.By convention, the simplex opposite `vertex(j)` of simplex `SI(i)` is `SN(i,j)`. If a simplex has one or more boundary facets, the nonexistent neighbors are represented by `NaN`.

Definitions

A simplex is a triangle/tetrahedron or higher-dimensional equivalent. A facet is an edge of a triangle or a face of a tetrahedron.

Examples

Example 1

Load a 3-D triangulation and use `TriRep` to compute the neighbors of all tetrahedra.

```load tetmesh trep = TriRep(tet, X) nbrs = neighbors(trep) ```

Example 2

Query a 2-D triangulation created using `DelaunayTri`.

```x = rand(10,1) y = rand(10,1) dt = DelaunayTri(x,y)```
Find the neighbors of the first triangle:
`n1 = neighbors(dt, 1)`

See Also

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