Partial Differential Equation Toolbox Release Notes


New Features, Bug Fixes, Compatibility Considerations

3-D finite element analysis

You can now solve partial differential equations with 3-D geometry. To do so, there is a new workflow that combines the geometry, mesh, and boundary conditions into a PDEModel object. You can also use this workflow for 2-D geometry. For details, see Solve Problems Using PDEModel Objects.

Equation coefficients and boundary conditions for 3-D problems

To specify problem coefficients or boundary conditions in 3-D geometry, you can use strings with a syntax similar to that of a 2-D problem. There is a new way of writing functions for coefficients in 3-D geometries. For details, see PDE Coefficients and Boundary Conditions.

Compatibility Considerations

To accommodate both 2-D and 3-D geometry, the format of boundary condition objects changed from that introduced in R2014b. The new object is BoundaryCondition Properties, and calling pdeBoundaryConditions now warns that it will be removed in a future release. If you saved a pdeBoundaryConditions object in an R2014b-format MAT file, then loading that file in R2015a can produce an error. Additionally, the syntax for specifying nonconstant boundary conditions has changed. Functions written in the previous syntax continue to work for now.

R2014b SyntaxR2015a Syntax
function bcMatrix = myfun(problem,region,state)function bcMatrix = myfun(region,state)

For details, see Changes to Boundary Conditions Object From R2014b.

Elliptic, parabolic, hyperbolic, nonlinear, eigenvalue solvers for 3-D problems

The main toolbox solvers now support problems with 3-D geometry. For a listing of functions that do or do not support 3-D geometry, see Functions That Support 3-D Geometry. Solvers take a model argument instead of the previous b, p, e, t arguments. For details, see the function reference pages.

3-D geometry import from STL files

Import the geometry for a 3-D problem in the STL file format using the importGeometry function. For details, see Create and View 3-D Geometry.

3-D unstructured meshing using tetrahedra

Create finite element meshes using the generateMesh function. For 3-D geometry, the meshes consist of tetrahedra. See Mesh Data for [p,e,t] Triples: 3-D.

Plot function to inspect 3-D solutions

The pdeplot3D function plots solutions on the boundaries of 3-D geometry. For details, see Plot 3-D Solutions.

Featured examples with 3-D geometry

There are two new featured examples related to linear elasticity that have 3-D geometry:

There is also a new example of plotting slices through a 3-D solution: Contour Slices Through a 3-D Solution.

To run the examples at the MATLAB® command line:

echodemo StrainedBracketExample
echodemo Eigenvaluesofa3DPlateExample
echodemo ContourSlices3DExample

pdebound and pdegeom reference pages removed

The pdebound and pdegeom reference pages have been replaced by the Boundary Conditions and 2-D Geometry documentation categories.


New Features, Bug Fixes

Functions for modular definition of boundary conditions

To specify PDE boundary conditions in a modular fashion, per edge or set of edges, use a pdeBoundaryConditions specification. For details, see Steps to Specify a Boundary Conditions Object.

pdeInterpolant object for solution interpolation

Interpolate a PDE solution to a set of points using evaluate on an interpolant. Create the interpolant using pdeInterpolant.


New Features, Bug Fixes

Damping option for hyperbolic solver

You can include damping in the hyperbolic solver in matrix form. There is a new example of dynamics of a damped cantilever beam that shows how to use this feature.


New Features, Bug Fixes

Display option in hyperbolic and parabolic solvers

You can disable the display of internal ODE solution details that the hyperbolic and parabolic solvers report. To disable the display, set the Stats name-value pair to 'off'.

Eigenvalue example

There is a new example of eigenvalues of a circular membrane. View the example here. To run the example at the MATLAB command line:

echodemo eigsExample


New Features, Bug Fixes

Performance and robustness enhancements in meshing algorithm

The meshing (geometry triangulation) functions in initmesh and adaptmesh provide an enhancement option for increased meshing speed and robustness. Choose the enhanced algorithm by setting the MesherVersion name-value pair to 'R2013a'. The default MesherVersion value of 'preR2013a' gives the same mesh as previous toolbox versions.

The enhancement is available in pdetool in the Mesh > Parameters > Mesher version menu.

New example

There is a new example of heat distribution in a radioactive rod. View the example here. To run the example at the MATLAB command line:

echodemo radioactiveRod


New Features, Compatibility Considerations

Coefficients of parabolic and hyperbolic PDEs that can be functions of the solution and its gradient

You can now solve parabolic and hyperbolic equations whose coefficients depend on the solution u or on the gradient of u. Use the parabolic or hyperbolic commands, or solve the equations using pdetool. For details, see the function reference pages.

Graphics export from pdetool

You can save the current pdetool figure in a variety of image formats. Save the figure using the File > Export Image menu. See File Menu.

pdegplot labels edges and subdomains

pdegplot now optionally labels:

  • The edges in the geometry

  • The subdomains in the geometry

To obtain these labels, set the edgeLabels or subdomainLabels name-value pairs to 'on'. For details, see the pdegplot reference page.

New examples

There is a new example of uniform pressure load on a thin plate. View the example here. To run the example at the MATLAB command line:

echodemo clampedSquarePlateExample

There is a new example of nonlinear heat transfer in a thin plate. View the example here. To run the example at the MATLAB command line:

echodemo heatTransferThinPlateExample

There is a new example of a system of coupled PDEs. View the example here. To run the example at the MATLAB command line:

echodemo deflectionPiezoelectricActuator

pdesmech shear strain calculation change

The pdesmech function now calculates shear strain according to the engineering shear strain definition. This has always been the documented behavior. However, the previous calculation was performed according to the tensor shear strain calculation, which gives half the value of the engineering shear strain.

Compatibility Considerations

pdesmech now returns shear strain values exactly twice as large as before.

Compatibility Summary

ReleaseFeatures or Changes with Compatibility Considerations
R2015aEquation coefficients and boundary conditions for 3-D problems
R2012bpdesmech shear strain calculation change
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