# Documentation

### This is machine translation

Translated by
Mouseover text to see original. Click the button below to return to the English verison of the page.

# TriRep

Class: TriRep

(Not recommended) Triangulation representation

### Note

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

## Syntax

```TR = TriRep(TRI, X, Y) TR = TriRep(TRI, X, Y, Z) TR = TriRep(TRI, X) ```

## Description

`TR = TriRep(TRI, X, Y)` creates a 2-D triangulation representation from the triangulation matrix `TRI` and the vertex coordinates `(X, Y)`. `TRI` is an `m`-by-3 matrix that defines the triangulation in face-vertex format, where `m` is the number of triangles. Each row of `TRI` is a triangle defined by indices into the column vector of vertex coordinates ```(X, Y)```.

`TR = TriRep(TRI, X, Y, Z)` creates a 3-D triangulation representation from the triangulation matrix `TRI` and the vertex coordinates `(X, Y, Z)`. `TRI` is an `m`-by-3 or `m`-by-4 matrix that defines the triangulation in simplex-vertex format, where `m` is the number of simplices; triangles or tetrahedra in this case. Each row of `TRI` is a simplex defined by indices into the column vector of vertex coordinates `(X, Y, Z)`.

`TR = TriRep(TRI, X)` creates a triangulation representation from the triangulation matrix `TRI` and the vertex coordinates `X`. `TRI` is an `m`-by-`n` matrix that defines the triangulation in simplex-vertex format, where `m` is the number of simplices and `n` is the number of vertices per simplex. Each row of `TRI` is a simplex defined by indices into the array of vertex coordinates `X`. `X` is an `mpts`-by-`ndim` matrix where `mpts` is the number of points and `ndim` is the dimension of the space where the points reside, where 2 ≤ `ndim` ≤ 3.

## Examples

Load a 3-D tetrahedral triangulation compute the free boundary. First, load triangulation `tet` and vertex coordinates `X`.

`load tetmesh`

Create the triangulation representation and compute the free boundary.

```trep = TriRep(tet, X); [tri, Xb] = freeBoundary(trep);```