Modelica.UsersGuide.ReleaseNotes

This section summarizes the changes that have been performed on the Modelica standard library. Furthermore, it is explained in Modelica.UsersGuide.ReleaseNotes.VersionManagement how the versions are managed. This is especially important for maintenance (bug fix) releases where the main version number is not changed.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Package Content

Name	Description
VersionManagement	Version Management
Version_4_0_0	Version 4.0.0 (June 4, 2020)
Version_3_2_3	Version 3.2.3 (January 23, 2019)
Version_3_2_2	Version 3.2.2 (April 3, 2016)
Version_3_2_1	Version 3.2.1 (August 14, 2013)
Version_3_2	Version 3.2 (Oct. 25, 2010)
Version_3_1	Version 3.1 (August 14, 2009)
Version_3_0_1	Version 3.0.1 (Jan. 27, 2009)
Version_3_0	Version 3.0 (March 1, 2008)
Version_2_2_2	Version 2.2.2 (Aug. 31, 2007)
Version_2_2_1	Version 2.2.1 (March 24, 2006)
Version_2_2	Version 2.2 (April 6, 2005)
Version_2_1	Version 2.1 (Nov. 11, 2004)
Version_1_6	Version 1.6 (June 21, 2004)
Version_1_5	Version 1.5 (Dec. 16, 2002)
Version_1_4	Version 1.4 (June 28, 2001)

Modelica.UsersGuide.ReleaseNotes.VersionManagement

Development branches

Further development and maintenance of the Modelica Standard Library is performed with two branches on the public GitHub repository of the Modelica Association.

Since version 4.0.0 the Modelica Standard Library uses semantic versioning following the convention:

MAJOR.MINOR.BUGFIX

This provides a mechanism for maintaining releases and bug-fixes in a well defined way and is inspired by (but not identical to) https://semver.org.

Main development branch

Name: "master"

This branch contains the actual development version, i.e., all bug-fixes and new features. New features must have been tested before including them. However, the exhaustive tests for a new version are (usually) not performed. This version is usually only be used by the developers of the Modelica Standard Library and is not utilized by Modelica users.

Maintenance branch

Name: "maint/4.0.x"

This branch contains the released Modelica Standard Library version (e.g., v4.0.0) where all bug-fixes since this release date are included (also consecutive BUGFIX versions 4.0.1, 4.0.2, etc., up to when a new MINOR or MAJOR release becomes available; i.e., there will not be any further BUGFIX versions (i.e., 4.0.x) of a previous release). These bug-fixes might not yet be tested with all test cases or with other Modelica libraries. The goal is that a vendor may take this version at any time for a new release of its software, in order to incorporate the latest bug fixes.

Contribution workflow

The general contribution workflow is usually as follows:

1. Fork the repository to your account by using the Fork button of the GitHub repository site.
2. Clone the forked repository to your computer. Make sure to checkout the maintenance branch if the bug fix is going to get merged to the maintenance branch.
3. Create a new topic branch and give it a meaningful name, like, e.g., "issue2161-fix-formula".
4. Do your code changes and commit them, one change per commit.
   Single commits can be copied to other branches.
   Multiple commits can be squashed into one, but splitting is difficult.
5. Once you are done, push your topic branch to your forked repository.
6. Go to the upstream https://github.com/modelica/ModelicaStandardLibrary.git repository and submit a Pull Request (PR).
   • If the PR is related to a certain issue, reference it by its number like this: #2161.
   • Once a pull request is opened, you can discuss and review the potential changes with collaborators and add follow-up commits before the changes are merged into the repository.
   • If you have not already signed the Modelica Association Contributor License Agreement (CLA) you need to do so one-time.
     You can sign the CLA electronically using the CLA Assistant service and your GitHub account. There is no need to scan and send any documents by mail.
7. Update your branch with the requested changes. If necessary, merge the latest "master" branch into your topic branch and solve all merge conflicts in your topic branch.

There are some special guidelines for changes to the maintenance branch.

• Every change to the maintenance branch has to get cherry-picked at the "master" branch (see above), too.
• When a new BUGFIX release is due the annotations "version" and "versionDate" need to be updated.
  Example:

  annotation(version      = "4.0.1",
             versionDate  = "2020-09-29",
             dateModified = "2020-09-29 07:40:19Z",
             revisionId   = "$F​ormat:%h %ci$")
           

  The "dateModfied" is optional but might help identify the exact creation time of a release. The "revisionId" field is a special annotation to identify the exact commit that the released version represents.
  Example:

  Running the export command "git archive -o msl.zip v4.0.0" will expand the above "revisionId" place holder to something like:

  revisionId = "c04e23a0d 2020-04-01 12:00:00 +0200$"

As a recommendation, a valid bug-fix to the maintenance branch may contain one or more of the following changes.

• Correcting an equation.
• Correcting attributes quantity/unit/defaultUnit in a declaration.
• Improving/fixing the documentation.
• Introducing a new name in the public section of a class (model, package, ...) or in any section of a partial class is not allowed. Since otherwise, a user might use this new name and when storing its model and loading it with an older bug-fix version, an error would occur.
• Introducing a new name in the protected section of a non-partial class should only be done if absolutely necessary to fix a bug. The problem is that this might be non-backward compatible, because a user might already extend from this class and already using the same name.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_4_0_0

Version 4.0.0 is not backward compatible to previous versions. A tested conversion script is provided to transform models and libraries of previous versions 3.x.y to the new version. Short Overview:

• About 649 issues (including 432 pull requests) have been addressed for this release.
• This version is based on the recent Modelica language standard version 3.4.
• The library version (i.e., "4.0.0") follows semantic versioning using the convention MAJOR.MINOR.BUGFIX (see Version Management for details) and was decoupled from the version of the utilized version of the Modelica language standard.
• Obsolete classes of previous versions 3.x.y have been replaced.
• Obsolete classes, that could not be automatically converted to alternative implementations, have been moved to library ObsoleteModelica4.
• Major emphasis was put on improvements of the overall quality with respect to class naming and package structuring, conventions and style guide-lines, icons, documentation style and example models. The following sublibraries have been renamed.
  1. Modelica.SIunits → Modelica.Units.{SI, NonSI, Conversions}
  2. Modelica.Electrical.MultiPhase → Modelica.Electrical.Polyphase
  3. Modelica.Electrical.QuasiStationary → Modelica.Electrical.QuasiStatic
• The licenses of the utilized open-source third-party software components as well as the BSD 3-clause license of the Modelica Standard Library itself are available as separate resources.

The exact difference between package Modelica version 4.0.0 and version 3.2.3 is summarized in a comparison table.

The following Modelica packages have been tested that they work together with this release of package Modelica (alphabetical list). Hereby simulation results of the listed packages have been produced with package Modelica version 3.2.3 and compared with the simulation results produced with version 4.0.0 Beta.1. The tests have been performed with Dymola 2020/2020x/2021:

The following new libraries have been added:

The following new components have been added to existing libraries:

The following existing components have been improved in a backward compatible way:

The following existing components have been changed in a non-backward compatible way:

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_2_3

Version 3.2.3 is backward compatible to version 3.2.2, that is models developed with versions 3.0, 3.0.1, 3.1, 3.2, 3.2.1 or 3.2.2 will work without any changes also with version 3.2.3. This version is a "clean-up" with major emphasis on quality improvement and tool compatibility. The goal is that all Modelica tools will support this package and will interpret it in the same way. Short Overview:

• About 557 issues (including pull requests) have been addressed for this release.
• 94 component models and blocks, 36 example models and 9 functions are newly included.
• The license has been changed to BSD 3-clause, visit: https://modelica.org/licenses/modelica-3-clause-bsd.

The exact difference between package Modelica version 3.2.3 and version 3.2.2 is summarized in a comparison table.

The following new libraries have been added:

The following new components have been added to existing libraries:

The following existing components have been marked as obsolete and will be removed in a future release:

The following existing components have been improved in a backward compatible way:

The following existing components have been changed in a non-backward compatible way:

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_2_2

Version 3.2.2 is backward compatible to version 3.2.1, that is models developed with versions 3.0, 3.0.1, 3.1, 3.2, or 3.2.1 will work without any changes also with version 3.2.2 (with exception of the, usually uncritical, non-backwards compatible changes listed below with regards to external object libraries, and one bug fix introduced in 3.2.1 Build.3 for non-circular pipes that can be non-backwards compatible if a user constructed a new pipe model based on Modelica.Fluid.Pipes.BaseClasses.WallFriction.PartialWallFriction, see details below).

• This version of the Modelica package is fully compatible to Modelica Specification 3.2 revision 2.
   
• About 240 tickets have been fixed in this release and the previous maintenance releases:
  • Version 3.2.1 Build.3 (July 30, 2015) with respect to 3.2.1 Build.2 (August 14, 2013):
    About 103 tickets have been fixed for this maintenance release.
     
  • Version 3.2.1 Build.4 (September 30, 2015) with respect to 3.2.1 Build.3 (July 30, 2015):
    • About 10 tickets have been fixed for this maintenance release. Critical tickets:
    • Ticket 1768 fixes an issue with block CombiTimeTable (wrong output when using fixed time step integrator with time step greater than table resolution).
    • Ticket 1758 states that simulation of Modelica.Fluid.Examples.HeatingSystem fails in Dymola 2016 if option "pedantic mode for checking Modelica semantics" is set. This issue was not fixed in the library due to the following reasons:
      The Modelica.Fluid library uses a particular pattern to define some parameters resulting in a cyclic dependency of parameters if only incident information is taken into account. According to Modelica Specification 3.2 revision 2 this is not allowed (and therefore Dymola 2016 correctly reports errors if the pedantic flag is set). In ticket 1320 this issue was resolved for Modelica Specification 3.3 revision 1 by allowing cyclic parameter definitions if the cycles disappear when evaluating parameters that have annotation Evaluate=true. Modelica.Fluid is correct with respect to Modelica Specification 3.3 revision 1. Changing the Modelica.Fluid library for 3.2.1 build.4 so that no cyclic parameter dependencies would be present anymore would (a) result in a non-backwards compatible change and (b) make the usage of Modelica.Fluid less convenient. For this reason Modelica.Fluid is not changed. (Practically, this means for example that the pedantic flag in Dymola 2016 needs to be switched off, when using the Modelica.Fluid library in version 3.2.1 build 4 and any previous version).
    • In ticket 1757 it is (correctly) stated that the example model PsychrometricData was moved from Modelica.Media.Air.MoistAir.PsychrometricData and that this is a non-backwards compatible change. This non-backwards compatible change is accepted, because it fixes a circular dependency (a model references a package in which it resides), for details see ticket 1679. Fixing this ticket is seen as of much higher priority, as the small drawback that an example model is moved (and the probability is very high that this moved model is not used in any user model).
       
  • Version 3.2.2 Build.2 (March 16, 2016) with respect to 3.2.1 Build.4 (September 30, 2015):
    About 130 tickets have been fixed for this release.
    The ModelicaStandardTables object library (.lib, .dll, .a, .so, depending on tool) has been split into the libraries ModelicaStandardTables, ModelicaMatIO, zlib and the new object library ModelicaIO has been added.
    For a tool vendor this can be a non-backwards compatible change if the same object libraries have been used in the past for different releases of package Modelica. In Resources/C-Sources/readme.txt the issue is explained in detail and how to resolve it. For a user this might be a non-backwards compatible change if he/she implemented an own external C interface function to one of the functions in the ModelicaStandardTables, ModelicaMatIO or zlib libraries. In this case, the library annotations to these functions need to be adapted.
     
• In version 3.2.1 Build.3 a new argument crossArea was introduced in the functions of Modelica.Fluid.Pipes.BaseClasses.WallFriction.PartialWallFriction to fix a subtle bug for the calculation of pipe friction for non-circular pipes, see #1601 and #1656. If a user utilized a pipe model of Modelica.Fluid.Pipes, this does not matter because the pipe models have been improved in a fully backwards compatible way. However, if the user constructed an own pipe model based on the partial package PartialWallFriction and calls the functions defined in PartialWallFriction with positional (and not named) arguments, then a unit warning or error will occur (depending on the tool and tool-specific settings) because the new argument crossArea has unit [m2] and the previous argument at this place, roughness, has unit [m]. If the warning is ignored, the simulation result will be wrong, because the crossArea is used as roughness. The user needs to fix this by adapting his/her pipe model so that the crossArea is used in the function calls, or by using named function arguments.

The exact difference between package Modelica version 3.2.2 and version 3.2.1 is summarized in the following two comparison tables:

• Difference 3.2.2 to 3.2.1 Build 4,
• Difference 3.2.1 Build 4 to 3.2.1 Build 2.

This release of package Modelica, and the accompanying ModelicaTest, has been tested with the following tools (the tools are listed alphabetically. At the time of the test, some of the tools might not yet supported the complete Modelica package. For more details of the tests see #1867):

• Dymola 2017 Beta.1 (Windows 64 bit, "Check" with pedantic flag, that is checking strict Modelica compliance, and "Check with Simulation").
  #1924: Regression testing of 3.2.2+build.0-beta.2 using Dymola 2017 Dev 4 with respect to 3.2.1+build.4 reference files
  #1949: Regression testing of 3.2.2+build.0-beta.3 using Dymola 2017 Beta 1 with respect to 3.2.1+build.4 reference files
• LMS Imagine.Lab Amesim 14.2 and LMS Imagine.Lab Amesim 15 (development build). No previously unreported regressions have been detected.
• Maplesim Parser
• OpenModelica 1.9.4 Beta.2 (Windows, Linux, Mac)

The following Modelica packages have been tested that they work together with this release of package Modelica (alphabetical list):

• AirConditioning Library 1.12 (Modelon)
• Buildings 2.1.0 (LBNL)
• Electric Power Library 2.2.3 (Modelon)
• Engine Dynamics Library 1.2.5 (Modelon)
• FlexibleBodies 2.2 (DLR)
• FlightDynamics 1.0.1 (DLR)
• FluidDissipation 1.1.8 (XRG Simulation)
• Fuel Cell Library 1.3.3 (Modelon)
• Heat Exchanger Library 1.4.1 (Modelon)
• Human Comfort Library 2.1.0 (XRG Simulation)
• HVAC Library 2.1.0 (XRG Simulation)
• Hydraulics Library 4.4 (Modelon)
• Hydronics Library 2.1.0 (XRG Simulation)
• Hydro Power Library 2.6 (Modelon)
• Liquid Cooling Library 1.5 (Modelon)
• Modelica_Synchronous 0.92.1
• Modelica_LinearSystems2 2.3.4
• Modelica_StateGraph2 2.0.3
• Optimization 2.2.2 (DLR)
• PowerTrain 2.4.0 (DLR)
• Pneumatics Library 2.0 (Modelon)
• Thermal Power Library 1.12 (Modelon)
• Vapor Cycle Library 1.3 (Modelon)
• Vehicle Dynamics Library 2.3 (Modelon)

The following new libraries have been added:

The following new components have been added to existing libraries:

The following existing components have been changed in a non-backward compatible way:

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_2_1

Version 3.2.1 is backward compatible to version 3.2, that is models developed with versions 3.0, 3.0.1, 3.1, or 3.2 will work without any changes also with version 3.2.1. This version is a "clean-up" with major emphasis on quality improvement and tool compatibility. The goal is that all Modelica tools will support this package and will interpret it in the same way. Short Overview:

• This version of the Modelica package is fully compatible to Modelica Specification 3.2 revision 2.
  (Especially, some operators used in package Modelica, such as "rooted", have been standardized in 3.2 rev. 2, as well as vendor specific annotations. Furthermore, ambiguous/unclear descriptions in the specification have been corrected/improved. One important improvement in packages Modelica and ModelicaTest is that the initialization has been fully defined in all example models, in order that all tools can produce the same result without relying on tool heuristics).
• About 400 tickets have been fixed for this release, and especially all compliance issues and all relevant defect issues.
• An open source implementation of the table blocks has been provided by ITI GmbH. This work has been paid by Modelica Association. As a result, all parts of package Modelica are now available in a free implementation. Additionally new features have been added to the table blocks by this implementation:
  • The table outputs can be differentiated once.
  • Support of binary MATLAB MAT-file formats v6 and v7
  • New option ConstantSegments for parameter Smoothness
  • New option NoExtrapolation for parameter Extrapolation
  • Support of tables provided in the C-Code (usertab.c, for realtime systems without file system)
• Icons have been re-designed by Wolfram Research to provide a more modern view.
• The Modelica.Media.Air.MoistAir media model has been improved so that it can be used in a temperature range of 190 ... 647 K (previously: 240 ... 400 K).
• New media models for air (ReferenceAir with a large operating range: 30 ... 2000 K, 0 ... 2000 MPa), for moist air (ReferenceMoistAir with a large operating range: 143.15 ... 2000 K, 0 .. 10 MPa; but 1-2 orders of magnitude slower as Modelica.Media.Air.MoistAir), and the refrigerant R134a are included in the Modelica.Media library in order to improve the modeling of air conditioning systems especially in aircraft. These models have been developed by XRG Simulation GmbH as part of the Clean Sky JTI project (Project number: 296369; Theme: JTI-CS-2011-1-SGO-02-026). The partial financial support by the European Union for this development is highly appreciated.
• 60 models and blocks and 90 functions are newly included, for details see below.

This release of package Modelica, and the accompanying ModelicaTest, has been tested with the following tools (the tools are listed alphabetically. At the time of the test, some of the tools might not yet supported the complete Modelica package):

• CyModelica
• Dymola 2014 (Windows 64 bit)
  Regression test results with regards to Modelica 3.2 are available in ticket #1114.
• Dymola 2014 FD01 development with pedantic flag (Windows 64 bit)
  ("pedantic flag" means that strict Modelica compliance is checked. Dymola 2014 fails with pedantic flag, e.g., because the annotation DocumentationClass was not standardized when this version of Dymola was released).
• Maplesim Parser
• MWorks 3.2
• OpenModelica 1.9.0 Beta4+dev (Windows, Linux, Mac)
  Test reports for the daily builds are available here.
• SimulationX 3.6

The following Modelica packages have been tested that they work together with this release of package Modelica (alphabetical list):

• Buildings 1.4 (LBNL)
• FlexibleBodies 2.0.1 (DLR)
• Modelica_Synchronous 0.91 (DLR)
• Optimization 2.2 (DLR)
• PowerTrain 2.2.0 (DLR)

The new open source tables have been tested by T. Beutlich (ITI):

• 193 Modelica test models for compatibility check with previous table implementation (available in ModelicaTest.Tables). Performed tests with SimulationX 3.5.707 (32 bit) and Dymola 2013 FD01 (32 bit). Furthermore a basic check was performed in OpenModelica to make sure it works in general.
• The two C source files (Modelica/Resources/C-Sources/ModelicaStandardTables.c; ModelicaMatIO.c) have been tested to successfully compile for the following platforms
     Windows 32 and 64 bit
     Linux 32 and 64 bit
     dSPACE SCALEXIO
     dSPACE DS1005 (no file system)
     dSPACE DS1006 (no file system)
     dSPACE DS1401 (no file system)
• The following compilers/environments have been used for the platform evaluation
     Microsoft compilers (VC6 and ≥ VS2005 (Win32 and x64))
     MinGW (GCC 4.4.0 and GCC 4.7.2)
     Cygwin (GCC 4.3.0)
     Open WATCOM 1.3
     LCC 2.4.1
     Borland C/C++ (free command line tools) 5.5
     GCC 4.x on Linux
     GCC 3.3.5 (for DS1006)
     Microtec PowerPC Compiler 3.7 (for DS1005)

The exact difference between package Modelica version 3.2 and version 3.2.1 is summarized in a comparison table.

About 400 trac tickets have been fixed for this release. An overview is given here. Clicking on a ticket gives all information about it.

The following new components have been added to existing libraries:

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_2

Version 3.2 is backward compatible to version 3.1, i.e., models developed with versions 3.0, 3.0.1, or 3.1 will work without any changes also with version 3.2. This version is a major improvement:

• 357 models and blocks and 295 functions are newly included.
• 7 new libraries are included.
• The icons of the library are newly designed to provide a modern, unified view, see Modelica.Icons.
• All non-Modelica files, such as images, pdf-files, C-source files, scripts are moved to the new directory "Modelica\Resources". Furthermore, all file references are changed to URIs as introduced in Modelica 3.1 (e.g., a file with the file name "Modelica/Resources/Images/xxx" is referenced as "modelica://Modelica/Resources/Images/xxx").
• All physical models that dissipate heat (such as electrical elements, electrical machines, bearings, dampers, etc.), have now an optional heat port to which the dissipated energy is flowing, if activated. This will significantly improve design studies about the thermal efficiency of technical systems.
• All electrical machines in the Machines library have now a "Losses" tab in the parameter menu to optionally model machines losses such as frictional losses, stator core losses or stray load losses, respectively.
• All electrical machines in the Machines library have now a "powerBalance" result record, summarizing converted power and losses.

Version 3.2 is slightly based on the Modelica Specification 3.2. It uses the following new language elements (compared to Modelica Specification 3.1):

• Operator records and overloaded operators.
• Functions as input arguments to functions.
• Improved expandable connectors (variables declared in expandable connectors are ignored if not referenced).

A large part of the new classes have been developed with partial financial support by BMBF (BMBF Förderkennzeichen: 01IS07022F) within the ITEA2 project EUROSYSLIB. We highly appreciate this funding.

The following new libraries have been added:

The following new components have been added to existing libraries:

The following existing components have been improved in a backward compatible way:

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, but, e.g., units are wrong or errors in documentation):

The following trac tickets have been fixed:

Note:

• Libraries Modelica_FundamentalWave and Modelica_QuasiStationary are included in this version in an improved form.
• From library Modelica_LinearSystems2, the sublibraries Math.Complex, Math.Vectors and Math.Matrices are included in this version in an improved form.
• From library Modelica_StateGraph2, the sublibrary Blocks is included in this version in an improved form.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_1

Version 3.1 is backward compatible to version 3.0 and 3.0.1, i.e., models developed with version 3.0 or 3.0.1 will work without any changes also with version 3.1.

Version 3.1 is slightly based on the Modelica Specification 3.1. It uses the following new language elements (compared to Modelica Specification 3.0):

• Prefix stream and built-in operators inStream(..) and actualStream(..) in Modelica.Fluid.
• Annotation connectorSizing in Modelica.Fluid.
• Annotation inverse in Modelica.Media.
• Annotations versionBuild, dateModified, revisionId at the root level annotation of package Modelica, to improve the version handling.
• Modifiers can be used in connectors instances (so balanced models are less restrictive). This allowed to make the implementation of conditional connectors (support and heatPort) in the Rotational, Translational and Electrical libraries simpler.

The following new libraries have been added:

The following new components have been added to existing libraries:

The following existing components have been improved in a backward compatible way:

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, but, e.g., units are wrong or errors in documentation):

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_0_1

This Modelica package is provided under the Modelica License 2 and no longer under Modelica License 1.1. There are the following reasons why the Modelica Association changes from Modelica License 1.1 to this new license text (note, the text below is not a legal interpretation of the Modelica License 2. In case of a conflict, the language of the license shall prevail):

1. The rights of licensor and licensee are much more clearly defined. For example:
   • The licensed work (Original Work) can be used in unmodified form in open source and commercial software (the licensee cannot change the license and the work must be provided without fees)
   • If a model component is copied out of a Modelica package under Modelica License 2 and is modified in order to adapt it to the needs of the modeler, then the result can be licensed under any license (including a commercial license).
   • It is practically not possible to change the license of a Modelica package under Modelica License 2 to another license, i.e., a licensee cannot change the license by adding material or changing classes, so the work must remain under Modelica License 2 (to be more precise, if the licensee makes modifications to the Original Work "which represents, as a whole, an original work of authorship", he/she can change the license to another license. However, for a Modelica package this would require a lot of changes which is usually unrealistic).
   • If an executable is constructed using a Modelica package under Modelica License 2, then this executable can be licensed under any license (including a commercial license).
   We hope that this compromise between open source contributors, commercial Modelica environments and Modelica users will motivate even more people to provide their Modelica packages freely under the Modelica License 2.
   
   
2. There are several new provisions that shall make law suites against licensors and licensees more unlikely (so the small risk is further reduced).

The following new components have been added to existing libraries:

The following existing components have been changed (in a backward compatible way):

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, but, e.g., units are wrong or errors in documentation):

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_3_0

Version 3.0 is not backward compatible to previous versions. A conversion script is provided to transform models and libraries of previous versions to the new version. Therefore, conversion should be automatic.

The following changes are present for the whole library:

• In the Modelica language version 3.0, several restrictions have been introduced to allow better checking, e.g., models on all levels must be balanced (number of equations = number of unknown variables - unknown variables that have to be defined when using the component). A few models of the Modelica Standard Library did not fulfill these new restrictions and had either to be moved to library ObsoleteModelica3 (e.g., Blocks.Math.TwoInputs) or had to be differently implemented (e.g., Media.Interfaces.PartialMedium.BaseProperties). The Modelica Standard Library version 3.0 fulfills all the restrictions of the Modelica Language version 3.0.
   
• The graphical annotations describing the layout of icon and diagram layer are changed from Modelica language version 1 to Modelica language version 3. This gives several significant improvements:
  Especially, the coordinate systems of icon and diagram layers are no longer coupled and therefore the size of the icon layer can be changed independently of the size of the diagram layer. Also it can be defined that the aspect ratio of a component icon is kept when changing its size in a model. This flag is set so that all icons of the Modelica Standard Library keep its aspect ratios. This is slightly non-backward compatible: If the aspect ratio was not kept when using a component from the Modelica Standard Library, it is now resized so that the aspect ratio is maintained.
   
• All non-standard annotations removed by:
  (1) Removing the annotation since without effect (e.g., "__Dymola_experimentSetupOutput", "Window", "Terminal" removed).
  (2) Renaming the annotation to a standard name (e.g., "Hide" renamed to "HideResult").
  (3) Renaming the annotation to a vendor specific name (e.g., "checkBox" renamed to "__Dymola_checkBox").
   
• All emulated enumerations (defined via packages and constants) have been replaced by "real" enumerations. User models are automatically correctly converted, provided the user models used the package constants previously. Existing models that use directly literal values for enumerations, might give in some cases wrong results (if the first constant of the emulated enumeration had value zero, whereas the first value of an enumeration is one).
   
• The operator "cardinality" will be removed in one of the next versions of the Modelica language, since it is a reflective operator and its usage significantly reduces the possibilities of advanced model checks (e.g., to guarantee that a model is "balanced", i.e., the number of equations and unknowns is identical, for all valid usages of the component). As a preparation for this change, all models that contain the "cardinality(..)" operator are rewritten: If possible the operator is removed. If this is not possible, it is only used in asserts to check that, e.g., a connector is connected at least once or is connected exactly once. In the next Modelica language version new language elements will be introduced to specify such a property check without the cardinality operator. Once these language elements are available, the cardinality operator will be removed completely from the Modelica Standard Library.
  The changes with respect to the cardinality(..) operator are usually not backward compatible. This is the reason for the changes of the Rotational and Translational library (see below).
   
• The design of the Rotational and Translational libraries have been changed (especially to remove the cardinality(..) operator, see above):
  • Components have a useSupport flag to enable or disable a support flange. If the support flange is enabled, it must be connected. If it is disabled, it must not be connected and the component is then internally grounded. The grounding is visualized in the icon.
  • The relative angle/distance and the relative speed of all force/torque elements (that need the relative speed) are by default defined with "StateSelect.prefer", i.e., to use these variables as preferred states. This improves the numerics if the absolute angle or the absolute distance are continuously increasing during operation (e.g., driving shaft of the wheels of a car). The effect is that relative angles/distances and speeds are used as states and the size of these variables is limited. Previously, the default was to use the absolute angle/distance and absolute speed of every inertia/mass which has the disadvantage that the absolute angle and or distance are state variables that grow in size continuously.
    A significant advantage is also, that default initialization is usually better, because a default value of zero for a relative angle/distance is usually what the user would like to have. Previously, say, the load was initialized to a non-zero angle and then the elastically coupled motor inertia had to be explicitly also initialized with this value. This is now, no longer needed. Since the default nominal value of 1 is usually too large for a relative quantity, the nominal values of the relative angle/distance was changed to 1e-4.
  • The two libraries have been restructured in sublibraries to cope with the growing number of components.
  • Finally, the Translational library has been made as similar as possible to the Rotational library by, e.g., adding missing components.
     
• The initialization of the MultiBody, Rotational and Translational libraries have been significantly simplified by removing the "initType" parameters and only using start/fixed values. This design assumes that a tool has special support for start/fixed values in the parameter menu.
   
• Nearly all parameters defined in the Modelica Standard Library had been defined with a default equation, e.g.,

  parameter Modelica.SIunits.Resistance R=1; 

  Physical parameters, such as a resistance, mass, gear ratio, do not have a meaningful default and in nearly all cases, the user of the corresponding component has to provide values for such parameters. If the user forgets this, a tool cannot provide diagnostics, since a default value is present in the library (such as 1 Ohm for the resistance). In most cases the model will simulate but will give wrong results due to wrong parameter values. To improve this situation, all physical parameter declarations in the Modelica Standard Library have been changed, so that the previous default becomes a start value. For example, the above declaration is changed to:

  parameter Modelica.SIunits.Resistance R(start=1);  

  This is a backward compatible change and completely equivalent from the perspective of the Modelica language. It is, however, advised that tools will print a warning or optionally an error message, if the start value of a parameter is defined, but no value for the parameter is given via a modification. Furthermore, it is expected, that the input field of a parameter menu is empty, if no default equation is defined, but only a start value. This shows clearly to the modeler that a value has to be provided.

The following new components have been added to existing libraries (note, the names in parentheses are the new sublibrary names that are introduced in version 3.0):

The following existing components have been changed in a non-backward compatible way (the conversion script transforms models and libraries of previous versions to the new version. Therefore, conversion should be automatic):

The following existing components have been improved in a backward compatible way:

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, but, e.g., units are wrong or errors in documentation):

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_2_2_2

Version 2.2.2 is backward compatible to version 2.2.1 and 2.2 with the following exceptions:

• Removal of package Modelica.Media.Interfaces.PartialTwoPhaseMediumWithCache (this was not yet utilized).
• Removal of the media packages in Modelica.Media.IdealGases.SingleGases that are not type compatible to Modelica.Media.Interfaces.PartialMedium, because a FluidConstants record definition is missing, for details, see Modelica.Media.IdealGases (this is seen as a bug fix).

An overview of the differences between version 2.2.2 and the previous version 2.2.1 is given below. The exact differences (but without differences in the documentation) are available in Differences-Modelica-221-222.html. This comparison file was generated automatically with Dymola's ModelManagement.compare function.

In this version, no new libraries have been added. The documentation of the whole library was improved.

The following new components have been added to existing libraries:

The following existing components have been improved:

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, but, e.g., units are wrong or errors in documentation):

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_2_2_1

Version 2.2.1 is backward compatible to version 2.2.

In this version, no new libraries have been added. The following major improvements have been made:

• The Documentation of the Modelica standard library was considerably improved:
  In Dymola 6, the new feature was introduced to automatically add tables for class content and component interface definitions (parameters and connectors) to the info layer. For this reason, the corresponding (partial) tables previously present in the Modelica Standard Library have been removed. The new feature of Dymola 6 has the significant advantage that all tables are now guaranteed to be up-to-date.
  Additionally, the documentation has been improved by adding appropriate description texts to parameters, connector instances, function input and output arguments etc., in order that the automatically generated tables do not have empty entries. Also new User's Guides for sublibraries Rotational and SIunits have been added and the User's Guide on top level (Modelica.UsersGuide) has been improved.
   
• Initialization options have been added to the Modelica.Blocks.Continuous blocks (NoInit, SteadyState, InitialState, InitialOutput). If InitialOutput is selected, the block output is provided as initial condition. The states of the block are then initialized as close as possible to steady state. Furthermore, the Continuous.LimPID block has been significantly improved and much better documented.
   
• The Modelica.Media library has been significantly improved:
  New functions setState_pTX, setState_phX, setState_psX, setState_dTX have been added to PartialMedium to compute the independent medium variables (= state of medium) from p,T,X, or from p,h,X or from p,s,X or from d,T,X. Then functions are provided for all interesting medium variables to compute them from its medium state. All these functions are implemented in a robust way for all media (with a few exceptions, if the generic function does not make sense for a particular medium).

The following new components have been added to existing libraries:

The following components have been improved:

The following errors have been fixed:

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_2_2

Version 2.2 is backward compatible to version 2.1.

The following new libraries have been added:

The following changes have been performed in the Modelica.Mechanics.MultiBody library:

• Component MultiBody.World has a new parameter driveTrainMechanics3D. If set to true, 3D mechanical effects of MultiBody.Parts.Mounting1D/Rotor1D/BevelGear1D are taken into account. If set to false (= default), 3D mechanical effects in these elements are not taken into account and the frame connectors to connect to 3D parts are disabled (all connections to such a disabled connector are also disabled, due to the new feature of conditional declarations in Modelica language 2.2)
• All references to "MultiBody.xxx" have been changed to "Modelica.Mechanics.MultiBodys.xxx" in order that after copying of a component outside of the Modelica library, the references still remain valid.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_2_1

This is a major change with respect to previous versions of the Modelica Standard Library, because many new libraries and components are included and because the input/output blocks (Modelica.Blocks) have been considerably simplified:

• An input/output connector is defined without a hierarchy (this is possible due to new features of the Modelica language). For example, the input signal of a block "FirstOrder" was previously accessed as "FirstOrder.inPort.signal[1]". Now it is accessed as "FirstOrder.u". This simplifies the understanding and usage especially for beginners.
• De-vectorized the Modelica.Blocks library. All blocks in the Modelica.Blocks library are now scalar blocks. As a result, the parameters of the Blocks are scalars and no vectors any more. For example, a parameter "amplitude" that might had a value of "{1}" previously, has now a value of "1". This simplifies the understanding and usage especially for beginners.
  If a vector of blocks is needed, this can be easily accomplished by adding a dimension to the instance. For example "Constant const[3](k={1,2,3})" defines three Constant blocks. An additional advantage of the new approach is that the implementation of Modelica.Blocks is much simpler and is easier to understand.

The discussed changes of Modelica.Blocks are not backward compatible. A script to automatically convert models to this new version is provided. There might be rare cases, where this script does not convert. In this case models have to be manually converted. In any case you should make a back-up copy of your model before automatic conversion is performed.

The following new libraries have been added:

The following existing libraries outside of the Modelica standard library have been improved and added as new libraries (models using the previous libraries are automatically converted to the new sublibraries inside package Modelica):

As a result, the ModelicaAdditions library is obsolete, because all components are either included in the Modelica library or are replaced by much more powerful libraries (MultiBody, StateGraph).

The following new components have been added to existing libraries.

The following bugs have been corrected:

Other changes:

• All connectors are now smaller in the diagram layer. This gives a nicer layout when connectors and components are used together in a diagram
• Default instance names are defined for all connectors, according to a new annotation introduced in Modelica 2.1. For example, when dragging connector "Flange_a" from the Rotational library to the diagram layer, the default connector instance name is "flange_a" and not "Flange_a1".
• The Modelica.Mechanics.Rotational connectors are changed from a square to a circle
• The Modelica.Mechanics.Translational connectors are changed from a green to a dark green color in order that connection lines can be better seen, especially when printed.
• The Modelica.Blocks connectors for Real signals are changed from blue to dark blue in order to distinguish them from electrical signals.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_1_6

Added 1 new library (Electrical.Polyphase), 17 new components, improved 3 existing components in the Modelica.Electrical library and improved 3 types in the Modelica.SIunits library. Furthermore, this User's Guide has been started. The improvements in more detail:

New components

New examples

The following new examples have been added to Modelica.Electrical.Analog.Examples:

CharacteristicThyristors, CharacteristicIdealDiodes, HeatingNPN_OrGate, HeatingMOSInverter, HeatingRectifier, Rectifier, ShowSaturatingInductor ShowVariableResistor

Improved existing components

In the library Modelica.Electrical.Analog.Ideal, a knee voltage has been introduced for the components IdealThyristor, IdealGTOThyristor, IdealDiode in order that the approximation of these ideal elements is improved with not much computational effort.

In the Modelica.SIunits library, the following changes have been made:

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_1_5

Added 55 new components. In particular, added new package Thermal.HeatTransfer for modeling of lumped heat transfer, added model LossyGear in Mechanics.Rotational to model gear efficiency and bearing friction according to a new theory in a robust way, added 10 new models in Electrical.Analog and added several other new models and improved existing models.

New components

Package-specific Changes

• All example models made encapsulated
• Upper case constants changed to lower case (cf. Modelica.Constants)
• Introduced Modelica.SIunits.Wavelength due to typo
• Introduced ModelicaAdditions.Blocks.Logical.Interfaces.Comparison due to typo
• Changed these components of *.Blocks to block class, which have not been already of block type
• Changed *.Interfaces.RelativeSensor to partial models

Class-specific Changes

Modelica.SIunits

Removed final from quantity attribute for Mass and MassFlowRate.

Modelica.Blocks.Math.Sum

Implemented avoiding algorithm section, which would lead to expensive function calls.

Modelica.Blocks.Sources.Step

block Step "Generate step signals of type Real"
        parameter Real height[:]={1} "Heights of steps";
 // parameter Real offset[:]={0} "Offsets of output signals";
// parameter SIunits.Time startTime[:]={0} "Output = offset for time < startTime";
// extends Interfaces.MO          (final nout=max([size(height, 1); size(offset, 1); size(startTime, 1)]));
        extends Interfaces.SignalSource(final nout=max([size(height, 1); size(offset, 1); size(startTime, 1)]));

Modelica.Blocks.Sources.Exponentials

Replaced usage of built-in function exp by Modelica.Math.exp.

Modelica.Blocks.Sources.TimeTable

Interface definition changed from

parameter Real table[:, :]=[0, 0; 1, 1; 2, 4] "Table matrix (time = first column)";

to

parameter Real table[:, 2]=[0, 0; 1, 1; 2, 4] "Table matrix (time = first column)";

Did the same for subfunction getInterpolationCoefficients.

Bug in getInterpolationCoefficients for startTime <> 0 fixed:

...
        end if;
  end if;
  // Take into account startTime "a*(time - startTime) + b"
  b := b - a*startTime;
end getInterpolationCoefficients;

Modelica.Blocks.Sources.BooleanStep

block BooleanStep "Generate step signals of type Boolean"
        parameter SIunits.Time startTime[:]={0} "Time instants of steps";
        parameter Boolean startValue[size(startTime, 1)]=fill(false, size(startTime, 1)) "Output before startTime";
        extends Interfaces.BooleanSignalSource(final nout=size(startTime, 1));
equation
        for i in 1:nout loop
//   outPort.signal[i] = time >= startTime[i];
          outPort.signal[i] = if time >= startTime[i] then not startValue[i] else startValue[i];
        end for;
end BooleanStep;

Modelica.Electrical.Analog

Corrected table of values and default for Beta by dividing them by 1000 (consistent with the values used in the NAND-example model):

• Semiconductors.PMOS
• Semiconductors.NMOS

Corrected parameter defaults, unit and description for TrapezoidCurrent. This makes the parameters consistent with their use in the model. Models specifying parameter values are not changed. Models not specifying parameter values did not generate trapezoids previously.

Icon layer background changed from transparent to white:

• Basic.Gyrator
• Basic.EMF
• Ideal.Idle
• Ideal.Short

Basic.Transformer: Replaced invalid escape characters '\ ' and '\[newline]' in documentation by '|'.

Modelica.Mechanics.Rotational

Removed arrows and names documentation from flanges in diagram layer

Modelica.Mechanics.Rotational.Interfaces.FrictionBase

Modelica.Mechanics.Rotational.Position

Replaced reinit by initial equation

Modelica.Mechanics.Rotational.RelativeStates

Bug corrected by using modifier stateSelect = StateSelect.prefer as implementation

Modelica.Mechanics.Translational.Interfaces.flange_b

Attribute fillColor=7 added to Rectangle on Icon layer, i.e., it is now filled with white and not transparent any more.

Modelica.Mechanics.Translational.Position

Replaced reinit by initial equation

Modelica.Mechanics.Translational.RelativeStates

Bug corrected by using modifier stateSelect = StateSelect.prefer as implementation

Modelica.Mechanics.Translational.Stop

Use stateSelect = StateSelect.prefer.

Modelica.Mechanics.Translational.Examples.PreLoad

Improved documentation and coordinate system used for example.

ModelicaAdditions.Blocks.Nonlinear.PadeDelay

Replaced reinit by initial equation

ModelicaAdditions.HeatFlow1D.Interfaces

Definition of connectors Surface_a and Surface_b:
flow SIunits.HeatFlux q; changed to flow SIunits.HeatFlowRate q;

MultiBody.Parts.InertialSystem

Icon corrected.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

Modelica.UsersGuide.ReleaseNotes.Version_1_4

• Several minor bugs fixed.
• New models:
  Modelica.Blocks.Interfaces.IntegerRealInput/IntegerRealOutput,
  Modelica.Blocks.Math.TwoInputs/TwoOutputs
  Modelica.Electrical.Analog.Ideal.IdealOpAmp3Pin,
  Modelica.Mechanics.Rotational.Move,
  Modelica.Mechanics.Translational.Move.
  

Version 1.4.1beta1 (February 12, 2001)

Adapted to Modelica 1.4

Version 1.3.2beta2 (June 20, 2000)

• New subpackage Modelica.Mechanics.Translational
• Changes to Modelica.Mechanics.Rotational:
  New elements:

  IdealGearR2T    Ideal gear transforming rotational in translational motion.
  Position        Forced movement of a flange with a reference angle
                                     given as input signal
  RelativeStates  Definition of relative state variables
  

• Changes to Modelica.SIunits:
  Introduced new types:
  type Temperature = ThermodynamicTemperature;
  types DerDensityByEnthalpy, DerDensityByPressure, DerDensityByTemperature, DerEnthalpyByPressure, DerEnergyByDensity, DerEnergyByPressure
  Attribute "final" removed from min and max values in order that these values can still be changed to narrow the allowed range of values.
  Quantity="Stress" removed from type "Stress", in order that a type "Stress" can be connected to a type "Pressure".
• Changes to Modelica.Icons:
  New icons for motors and gearboxes.
• Changes to Modelica.Blocks.Interfaces:
  Introduced a replaceable signal type into Blocks.Interfaces.RealInput/RealOutput:

  replaceable type SignalType = Real
  

  in order that the type of the signal of an input/output block can be changed to a physical type, for example:

  Sine sin1(outPort(redeclare type SignalType=Modelica.SIunits.Torque))
  

Version 1.3.1 (Dec. 13, 1999)

First official release of the library.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).