When a new version of Dymola is released, I check what changes have occurred to the advanced flags compared to the previous version so I can determine how this may affect our Modelica libraries and our internal test processes. I thought I would share the advanced flag changes I found in recent Dymola 2025x release, as this may save you a task or highlight an advanced flag that will be useful to you. If you are interested in more information on updating to a new version of Dymola, take a look at my previous post Making a Dymola Release Update.
New Advanced Flags
The table below lists all the new advanced flags which were added in Dymola 2025x.
| New Flag | Default Value | Description |
| Advanced.Beta.Check.TopLevelStructuralQuick | false | This enables the beta feature for a quicker top-level structural check, restricted to only check the top-level ignoring sub-components. |
| Advanced.Beta.Translation. FunctionsUseConstantsInsteadOfExpressions | false | A beta feature to use global constants instead of substituting expressions in functions, for arrays using non-built-in functions. It may give faster function execution but can require additional start values in the model. Part of improving the code generation for Modelica functions. |
| Advanced.Beta.UI.DefaultThickness | false | Beta feature to make it easier to use the standard default thickness from the Modelica Association (0.25mm). |
| Advanced.Editor.WarnConstraint | true | Enable additional warnings, when modifying a replaceable component also impacts the constraint that may be illegal. |
| Advanced.File.CommitLogAllBranches | true | Specify whether to include all branches in the commit log, or just current branch when using version management in Dymola. |
| Advanced.File.CommitLogSort | 2 | Specify how to sort the commit log; 0=date order, 1=author date order, 2=topo order, when using version management in Dymola. |
| Advanced.File.DisambiguateLibraries | true | To better handle multiple versions of libraries in the Dymola Libraries menu, enabling this flag will append the library name with the version number, if needed. |
| Advanced.FMI.UseInputSmoother | false | This flag was added for the support of FMU input interpolation for FMI 2 co-simulation FMUs. Enables input smoothing for non-discrete input variables to avoid integrator re-initializations when exporting co-simulation FMU, this is supported by Cvode, Ida, and the Dymola solvers Dassl, Lsodar, Euler, and Rkfix*. For details see section 3.8.5 FMI Support in Dymola in the Dymola 2025x Release Notes. |
| Advanced.FMI.UsePredictorCompensation | false | This flag was added for the support of FMU input interpolation for FMI 2 co-simulation FMUs. When using input smoothing (Advanced.FMI.UseInputSmoother), this enables predictor compensation to be applied to help the integrator manage discontinuous derivatives, this is supported by Cvode, Ida and the Dymola solver Dassl. For details see section 3.8.5 FMI Support in Dymola in the Dymola 2025x Release Notes. |
| Advanced.FMI3.ExposeDynamicArrays | true | This flag was added as part of the support for variable-size parameter arrays in FMI 3 FMUs. This will expose dynamic arrays for FMU export, it requires that the user sets them. For details see section 3.8.5 FMI Support in Dymola in the Dymola 2025x Release Notes. |
| Advanced.HTML.VariablesInModels | false | When enabled the variables of a model are displayed in the documentation layer. |
| Advanced.Simulation.CentralDifferenceJacobianDassl | false | When enabled the Jacobian (iteration matrix) is approximated using central difference instead of the default forward difference for the integration algorithm Dassl. Using this option can improve the accuracy, but the simulation might become less efficient. |
| Advanced.SSP.RotationAttribute | false | This enables the saving of rotations of connectors and components in exported SSP files; this is non-standard SSP (System Structure and Parameterization specification). |
| Advanced.Translation.EventMultiStage | true | Enables some form of event handling for multi-stage methods (Runge-Kutta). |
| Advanced.Translation.Log.Timing | false | When set to true, this flag will log the time taken for translation and compilation, and output these in the translation log. |
| Advanced.UI.SupportMultiLingual | false | This flag was included for the multi-lingual support added in the Dymola release. This permits the use of translation files, supplied in a library, to allow the library to be translated to other natural languages. For details see the section 3.2.2 Multi-lingual support for Dymola in the Dymola 2025x Release Notes. |
Removed Advanced Flags
There was only one advanced flag which was removed in Dymola 2025x, Advanced.FMI.ExposeDiscreteStatesForFMU. This flag controlled whether to expose discrete states in the XML file for an FMU.
Advanced Flags with Changed Default Values
There were two advanced flags where the default value changed in Dymola 2025x.
| Flag | Previous Default | New Default | Description |
| Advanced.FMI.RecreateArrays | false | true | This flag is a setup option to support arrays in FMI 2 import, and is now enabled by default. |
| Advanced.UI.WarnIfModelInPackageExtends | true | false | This change is part of the improved support for package-extends. This flag controls whether a warning about only using constant values for parameter changes in extended packages is shown in the parameter dialog. This warning is no longer displayed by default. For further details on the package-extends improvements, see section 3.2.3 Minor improvements in the Dymola 2025x Release Notes. |
Round Up
If you need help with setting these or any advanced flags in Dymola, then take a look at this earlier post, An Easier Way to Set Boolean Advanced Flags in Dymola.
To discover more details about the changes in Dymola 2025x, the release notes are available in the Dymola Resources GitHub here.
Written by: Hannah Hammond-Scott – Modelica Project Leader
Please get in touch if you have any questions or have got a topic in mind that you would like us to write about. You can submit your questions / topics via: Tech Blog Questions / Topic Suggestion.
