pdesurf

(To be removed) Surface plot of PDE node or triangle data

pdesurf will be removed in a future release. Use pdeplot instead. For more information, see Compatibility Considerations.

Syntax

pdesurf(p,t,u)

h = pdesurf(p,t,u)

Description

pdesurf(p,t,u) plots a 3-D surface using PDE node or triangle data as a height for a 2-D problem. The p and t arguments specify the geometry of the PDE problem.

If u is a column vector, pdesurf treats it as node data and uses continuous style and interpolated shading. If u is a row vector, pdesurf treats it as triangle data and uses discontinuous style and flat shading.

h = pdesurf(p,t,u) returns handles to the drawn axes objects.

Examples

Surface Plot of PDE Solution

Plot the solution of the equation $$-\Delta u=1$$ on the L-shaped membrane using the pdesurf function.

First, create a [p,e,t] mesh on the L-shaped membrane.

[p,e,t] = initmesh('lshapeg');

Solve the equation using the Dirichlet boundary conditions $$u=0$$ on $$\partial \Omega$$.

u = assempde('lshapeb',p,e,t,1,0,1);

Plot the solution at the mesh nodes. When plotting the solution at the nodes, the function uses continuous style and interpolated shading.

pdesurf(p,t,u)

Interpolate the solution from the mesh nodes to the triangle midpoints.

ut = pdeintrp(p,t,u);

Plot the interpolated solution. When plotting the solution as a triangle data, the function uses discontinuous style and flat shading.

pdesurf(p,t,ut)

Input Arguments

p — Mesh points

matrix

Mesh points, specified as a 2-by-Np matrix of points, where Np is the number of points in the mesh. For details on the mesh data representation, see initmesh.

Data Types: double

t — Mesh triangles

matrix

Mesh triangles, specified as a 4-by-Nt matrix of triangles, where Nt is the number of triangles in the mesh. For details on the mesh data representation, see initmesh.

Data Types: double

u — PDE solution

vector

PDE solution, specified as a vector.

The pdesurf function treats a column vector as node data and uses continuous style and interpolated shading. The function treats a row vector as triangle data and uses discontinuous style and flat shading.

Data Types: double

Output Arguments

h — Handles to graphics objects

vector

Handles to graphics objects, returned as a vector.

Tips

• For more control over a surface plot, use the pdeplot function.

Version History

Introduced before R2006a

R2022a: pdesurf will be removed

Not recommended starting in R2022a

pdesurf will be removed. Use pdeplot instead.

To update your code for plotting a solution u at nodes, change instances of the function call pdesurf(p,t,u) to the function call:

pdeplot(p,[],t,'XYData',u,'ZData',u,'ColorBar','off')

To update your code for plotting a solution ut at midpoints of mesh triangles, change instances of the function call pdecont(p,t,ut) to the function call:

pdeplot(p,[],t,'XYData',ut,'XStyle','flat', ...
               'ZData',ut,'ZStyle','discontinuos', ...
               'ColorBar','off')

pdeplot gives you more control over your surface plot.

Note that the legacy workflow that uses the [p,e,t] mesh is not recommended. New features might not be compatible with this legacy workflow. For description of the mesh data in the recommended workflow, see Mesh Data.