# Documentation

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# edgeAttachments

Class: TriRep

(Not recommended) Simplices attached to specified edges

### Note

`edgeAttachments(TriRep)` is not recommended. Use `edgeAttachments(triangulation)` instead.

`TriRep` is not recommended. Use `triangulation` instead.

## Syntax

```SI = edgeAttachments(TR, V1, V2) SI = edgeAttachments(TR, EDGE) ```

## Description

`SI = edgeAttachments(TR, V1, V2)` returns the simplices `SI` attached to the edges specified by `(V1, V2)`. `(V1, V2)` represents the start and end vertices of the edges to be queried.

`SI = edgeAttachments(TR, EDGE)` specifies edges in matrix format.

## Input Arguments

 `TR` Triangulation representation. `V1,V2` Column vectors of vertex indices into the array of points representing the vertex coordinates. `EDGE` Matrix specifying edge start and end points. `EDGE` is of size `m`-by-2, `m` being the number of edges to query.

## Output Arguments

 `SI` Vector cell array of indices into the triangulation matrix. `SI` is a cell array because the number of simplices associated with each edge can vary.

## Examples

### Example 1

Load a 3-D triangulation to compute the tetrahedra attached to an edge.

```load tetmesh trep = TriRep(tet, X); v1 = [15 21]'; v2 = [936 716]'; t1 = edgeAttachments(trep, v1, v2);```

You can also specify the input as edges.

```e = [v1 v2]; t2 = edgeAttachments(trep, e); isequal(t1,t2);```

### Example 2

Create a triangulation with `DelaunayTri`.

```x = [0 1 1 0 0.5]'; y = [0 0 1 1 0.5]'; dt = DelaunayTri(x,y); ```

Query the triangles attached to edge (1,5).

```t = edgeAttachments(dt, 1,5); t{:}; ```

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