A Reduced Model node (
) contains an online reduced model. The model could have been created in the same session or imported from a COMSOL Reduced Model file. A reduced model can be used, if applicable, as part of a time-dependent or frequency domain study, and it can be used for reconstruction of the full model from a compact, reduced model.
The following buttons are available at the top of the Settings window (or right-click the
Reduced Model node and choose them from the
Reduced Model context submenu):
Click Update Reduced Model Data (
) (or press F5) to update the reduced model data to take the current model state into account.
Choose Export Reduced Model (
) to export the reduced-order model to a COMSOL Reduced Model file (*.mphrom) that you specify in the
Export dialog box.
Click Reset to Default (
) to reset the reduced model properties to the default values (that is, the last values produced from a
Model Reduction node or imported). Clicking this button is useful if you have made edits for the settings that you do not want to keep. When updating the reduced model using the new settings, the updated values become the ones used as the original values for the reset.
It also possible to duplicate a Reduced Model node (by right-clicking and choosing
Duplicate or pressing Ctrl+Shift+D).
The Settings window for a
Reduced Model node contains the following sections:
Here you define the parameters for the reduced model. The Time (default:
t) for time-dependent models or the
Frequency (default:
freq) for a frequency-domain model.
The list in this section contains the model control inputs defined in the corresponding Model Reduction node’s
Model Control Inputs section (such as some global parameter). Also, the load factor, which is defined in the
Modal Solver node’s
Advanced section always appears in this list for modal models. If desired, you can redefine the expressions for the inputs and their variable names in the
Expression column and the
Variable column, respectively. The defined names can then be used in postprocessing, for example.
The list in this section contains the outputs defined in the corresponding Model Reduction node’s
Outputs section (a probe variable, for example). If desired, you can redefine their variable names in the
Variable column. The defined names can then be used in postprocessing, for example. If you have not defined a variable name in the
Model Reduction node, the output variables use default variable names such as
rom1.mr.out1.
Select the Add output dependent variables check box to add dependent variables corresponding to the output variables. The dependent variables are added to the
Dependent variables column. Such dependent variables also appear in the main study node that is used for the reduced model. For example, in a
Time Dependent study node, in the
Physics and Variables Selection section, the dependent variables from the reduced model appear under
Reduced model. Select the check boxes in the
Store output dependent variables column to store those dependent variables in the output from the study for use in postprocessing, for example.
The State reconstruction check box is only available if you have selected the
Enable reconstruction capability check box in the
Model Reduction node’s
Model Reduction Settings section. Select it to use state reconstruction for the dependent variables in the table below.
Also specify a Relative tolerance for the internal solver. The default value is decided when creating the model.
Under Matrices, all matrices that the reduced model solution includes are listed. The contents depend on if the reduced model is in the time domain or in the frequency domain. The list typically includes these matrices (among others):
Under Vectors, all vectors that the reduced model solution includes are listed. The contents depend on if the reduced model is in the time domain or in the frequency domain. The list typically includes these vectors (among others):
