Optimization Module Updates

For users of the Optimization Module, COMSOL Multiphysics® version 6.0 brings a Transformation feature for setting up simple shape variations, revamped parameter estimation functionality for least-squares objective analyses, improved support for transient optimization, and more easily accessible optimization features. Read more about the features below.

Shape Optimization

For Shape Optimization, there is a new Transformation feature for you to quickly set up simple shape variations. This supports translation, scaling, and rotation, as well as custom coordinate systems. The simplicity of the shape variations guarantees that it is possible to construct a CAD representation of the optimization result. You can see this new feature in the existing Optimization of a Photonic Crystal for Signal Filtering and Optimization of a Photonic Crystal for Demultiplexing models, as well as in a new model called Optimization of a Waveguide Iris Bandpass Filter — Transformation Version.

A revolved 2D electromagnetic coil showing the magnetic flux density with black lines and a blue center.
The magnetic flux density of a revolved 2D electromagnetic coil.

Parameter Estimation

The setup of parameter estimation models has been simplified using a set of new tools and interfaces. A new Global Least-Squares Objective feature is available through the Component node. This feature has an improved user interface relative to the old feature (which is still available through the Optimization interface). In addition, a new Parameter Estimation study step has also been introduced, while the old Parameter Estimation study step has been renamed Curve Fitting. With this new study step, you can set up a least-squares objective directly in the study step, without needing to add a General Optimization interface, and it can also be used with least-squares objective features. Several tutorial models make use of the new parameter estimation functionality, including (but not limited to) the Impedance Tube Parameter Estimation with Data Generation, Mooney–Rivlin Curve Fit, Estimation of Corrosion Kinetics Parameters, and Modeling Impedance in the Lithium-Ion Battery models.

A closeup view of the COMSOL Multiphysics UI showing the Model Builder with the Parameter Estimation node highlighted, the corresponding Settings window, a 1D plot in the Graphics window, and the Objective Probe Table.
The Impedance Tube Parameter Estimation with Data Generation model demonstrates how to use the new Parameter Estimation study step for estimating poroacoustic parameters based on impedance tube measurements.

Transient Optimization

Running transient sensitivity analyses is more robust with improvements to the solver settings. Additional robustness can be achieved by using fixed time steps and/or a new manual solver setting that allows solving the transient adjoint problem using the same time steps as the forward problem. Separately, a new Control Function feature allows for control variables that vary in time. The argument can be time, as in the Optimal Control for Heating of a Cylinder model, or chosen arbitrarily as shown in the Shape Optimization of a Rectangular Loudspeaker Horn in 3D model, where the feature is used for shape optimization. The Optimization of a Tesla Microvalve with Transient Flow model also makes use of the improvements for transient optimization.

The COMSOL Multiphysics UI showing the Model Builder with the Control Function node highlighted, the corresponding Settings window, a 1D plot in the Graphics window, and the Objective Probe Table.
The Optimal Control for Heating of a Cylinder model demonstrates how to use the Control Function feature to achieve a certain temperature as fast as possible. In this case, the feature is used with time as the argument.

Relocated Optimization Features

In addition to the new and updated functionality, how to access the user interfaces of the Optimization Module has changed. The optimization features that were located under the Definitions node have been elevated to exist on the same level as the physics interfaces. This change makes the optimization features easier to access and also more visible in the model tree.

New and Updated Tutorial Models

COMSOL Multiphysics® version 6.0 brings several new and updated tutorial models to the Optimization Module.