faceEdges

Find edges attached to specified faces

Syntax

EdgeID = faceEdges(g,RegionID)

EdgeID = faceEdges(g,RegionID,FilterType)

Description

EdgeID = faceEdges(g,RegionID) finds edges attached to the faces with ID numbers listed in RegionID.

EdgeID = faceEdges(g,RegionID,FilterType) returns internal, external, or all edges attached to the faces with ID numbers listed in RegionID. This syntax is valid for 3-D geometries only.

Examples

Edges Attached to Specified Faces of 3-D Geometry

Find edges attached to the top and bottom faces of a block.

Create a block geometry.

gm = multicuboid(3,2,1)

gm = 
  DiscreteGeometry with properties:

       NumCells: 1
       NumFaces: 6
       NumEdges: 12
    NumVertices: 8
       Vertices: [8x3 double]

Plot the geometry with the face labels.

pdegplot(gm,'FaceLabels','on','FaceAlpha',0.2)

Find edges attached to faces 1 and 2.

edgeIDs = faceEdges(gm,[1 2])

edgeIDs = 1×8

     1     2     3     4     5     6     7     8

Plot the geometry with the edge labels.

figure
pdegplot(gm,'EdgeLabels','on','FaceAlpha',0.2)

Edges Attached to Specified Faces of 2-D Geometry

Find edges attached to two faces of the L-shaped membrane.

Create a model and include this geometry. The geometry of the L-shaped membrane is described in the file lshapeg.

model = createpde();
gm = geometryFromEdges(model,@lshapeg)

gm = 
  AnalyticGeometry with properties:

       NumCells: 0
       NumFaces: 3
       NumEdges: 10
    NumVertices: 8
       Vertices: [8x2 double]

Plot the geometry with the face labels.

pdegplot(gm,'FaceLabels','on')

Find edges attached to faces 1 and 2.

edgeIDs = faceEdges(gm,[1 2])

edgeIDs = 1×8

     1     2     3     6     7     8     9    10

Plot the geometry with the edge labels.

figure
pdegplot(gm,'EdgeLabels','on')

Edges Attached to Internal and External Faces

Find edges attached to the side face of the inner cuboid in a geometry consisting of two nested cuboids.

Create a geometry that consists of two nested cuboids of the same height.

gm = multicuboid([2 5],[4 10],3)

gm = 
  DiscreteGeometry with properties:

       NumCells: 2
       NumFaces: 12
       NumEdges: 24
    NumVertices: 16
       Vertices: [16x3 double]

Plot the geometry with the face labels.

pdegplot(gm,'FaceLabels','on','FaceAlpha',0.2)

Find all edges attached to the side face of the inner cuboid.

edgeIDs = faceEdges(gm,6)

edgeIDs = 1×4

     1     5    10    12

From all edges attached to that face, return the edges attached to only the internal faces. Internal faces are faces shared between multiple cells.

edgeIDs = faceEdges(gm,6,'internal')

edgeIDs = 1×2

    10    12

From all edges attached to that face, return the edges attached to the external faces.

edgeIDs = faceEdges(gm,6,'external')

edgeIDs = 1×2

     1     5

Plot the geometry with the edge labels.

pdegplot(gm,'EdgeLabels','on','FaceAlpha',0.2)

Input Arguments

g — Geometry

DiscreteGeometry object | AnalyticGeometry object

Geometry, specified as a DiscreteGeometry or AnalyticGeometry object.

RegionID — Face ID

positive number | vector of positive numbers

Face ID, specified as a positive number or a vector of positive numbers. Each number represents a face ID.

FilterType — Type of edges to return

'all' (default) | 'internal' | 'external'

Type of edges to return, specified as 'internal', 'external', or 'all'. Depending on this argument, faceEdges returns these types of faces for a 3-D geometry:

• 'internal' — Edges attached to only internal faces. Internal faces are faces shared between multiple cells.

• 'external' — Edges attached to only external faces. External faces are faces not shared between multiple cells.

• 'all' — All edges attached to the specified cells.

Output Arguments

EdgeID — IDs of edges attached to specified faces

positive number | vector of positive numbers

IDs of edges attached to the specified faces, returned as a positive number or a vector of positive numbers.