isConnected Class: triangulation

Test if two vertices are connected by edge

Syntax tf = isConnected(TR,vstart,vend) tf = isConnected(TR,E)

Description tf = isConnected(TR ,vstart ,vend ) returns
a logical array of true or false values
that indicate whether the specified pairs of vertices are connected
by an edge. Element tf(j) is true when
the vertices, vstart(j) and vend(j) ,
are connected by an edge.

tf = isConnected(TR ,E ) specifies
the edge start and end indices in matrix E . Element tf(j) is true when
the vertices, E(j,1) and E(j,2) ,
are connected by an edge.

TR

Triangulation representation, see triangulation or delaunayTriangulation .

vstart

IDs of start vertices, specified as a column vector. Each vertex ID refers to a
vertex at the start of an edge.

vend

IDs of end vertices, specified as a column vector. Each vertex
ID refers to a vertex at the end of an edge.

E

IDs of the edge vertices, specified as a two-column matrix.
Each row of E corresponds to a candidate edge and
contains two IDs:

E(j,1) is the ID of the vertex
at the start of a candidate edge.

E(j,2) is the ID of the vertex
at end of the edge.

Output Arguments tf

Logical values, returned as a column vector. Element tf(j) is true when
either of the following are true:

The vertices, vstart(j) and vend(j) ,
are connected by an edge.

The vertices, E(j,1) and E(j,2) ,
are connected by an edge.

Otherwise, tf(j) is false.

Definitions Vertex ID A row number of the matrix, TR.Points . Use
this ID to refer a specific vertex in the triangulation.

Examples expand all

Load a 2-D triangulation.

load trimesh2d
TR = triangulation(tri,x,y); Determine whether vertices 3 and 117 are
connected by an edge.

isConnected(TR,3,117) ans =
1 The vertices are connected by an edge.

Determine whether vertices 3 and 164 are
connected by an edge.

isConnected(TR,3,164) ans =
0 The vertices are not connected by an edge.

X = gallery('uniformdata' ,[10,3],0);
DT = delaunayTriangulation(X); Determine whether vertices 2 and 7 are
connected by an edge.

E = [2 7];
isConnected(DT,E) ans =
1 The vertices are connected by an edge.

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