FAQ R10 - How is backward compatibility handled in Simcenter Amesim?

backward compatibility

Category: Simcenter Amesim

Topic: Installation/Release

Access Level: End User

Publish Date: February 2011

Question

How is backward compatibility handled in Simcenter Amesim?

The objective of this document is to define what "Backward compatibility" means in the context of using Simcenter Amesim, and to present a non-exhaustive list of restrictions. The latter relates to particular cases in which we cannot ensure that backward compatibility will work in each and every new version.

Answer

Definition

"Backward compatibility" is the ability of a new release of Simcenter Amesim to read, view, run and analyze older models generated by previous Simcenter Amesim versions.

The scope of this approach primarily impacts 3 areas:

• Model description: how models are stored.

• Data references: references to the data used by the models.

• Third party solutions: links from models to 3rd party tools.

Description of models

Models are mainly defined by a circuit topology and a list of parameter settings. In addition to this, models are compiled to embed numerical solvers and libraries of utilities.

Backward compatibility relates to the ability to read and manage the description of the models, which we refer to as "source" compatibility (as opposed to "binary" compatibility. More details about "binary" compatibility are given in the Restrictions paragraph later in the current document).

The migration of model descriptions from an older to a newer Simcenter Amesim release is done automatically through specific internal Simcenter Amesim tools. This way, we ensure that models are upgraded by keeping the circuit definition and by taking the latest versions of submodels into account.

Finally we ensure that we can recompile the models to:

• Embed solvers and utilities of the newer release.

• Start a simulation.

• Post process the results.

Data used by models

Data used by models in Simcenter Amesim are mostly classified in 2 types:

• Advanced parameters defined as lookup tables,

• Configuration files generated by Simcenter Amesim to store particular settings and results, making it possible to recover a configuration (such as for plots), or to replay a simulation (for example with the Animation tool).

During the migration from an older to a newer Simcenter Amesim release, we ensure that different formats of lookup tables remain readable and writable, and that configuration files remain supported.

Upgrade operations are either automatic or semi-automatic (using an assistant when user choices have to be made).

Third party tool links

Models can be linked weakly or strongly to 3rd party tools, e.g. when we perform coupling to co-simulate models in different software packages.

During the migration to a new Simcenter Amesim release, we check that the previously-supported version of a 3rd party tool remains operational. Limitations will be documented in the Known problems section of the Simcenter Amesim Release Notes. We also check that a newer version of the 3rd party tool is operational with the newest Simcenter Amesim release, and document the outcome of this validation in the Help of Simcenter Amesim.

Restrictions

• Forward compatibility "Forward compatibility" is not supported: a newer release of Simcenter Amesim cannot save files in a format that can be read by older Simcenter Amesim versions.

• Binary compatibility Our backward compatibility solution is based on "source" compatibility rather than "binary" compatibility. Consequently, if platforms (i.e., operating system, compiler, linker, 3rd party tools) are changed between two Simcenter Amesim releases, users have to recompile their Simcenter Amesim models and other utilities.

Starting point

The oldest Simcenter Amesim release for which we still ensure backward compatibility is called the "Baseline release". This version is currently Rev 8. For versions prior to this release, it might be possible to open and use models and data, but without any guarantee of backward compatibility.

Duration

For each new release of Simcenter Amesim, we ensure that models and data built by previous releases will be readable only back to the baseline release.

For example, when we release Revision 17, this version must be able to open and use models and data built in Revision 12.

Results

The Simcenter Amesim results produced after a simulation in the current version might not be identical to the results of the original simulation. This could be due to changes that we implemented in the solver algorithms, in utilities of libraries or in the submodels themselves.

A dedicated quality control scenario can be established between the customer and Siemens to specify expectations more accurately in terms of results based on predefined use cases.

Performance

The performance (i.e., execution speed) of Simcenter Amesim models and applications might not be the same between releases. For example, performance can decline due to the usage of more complex (but also more accurate) algorithms.

A dedicated quality control scenario can be established between the customer and Siemens to specify expectations more accurately in terms of performances based on predefined use cases.

Configuration files

Models sometimes use configuration files generated by Simcenter Amesim. Such configuration files are automatically upgraded when deploying a newer Simcenter Amesim release. However, certain features in a configuration file may become unsupported, e.g. in case of a major redesign in Simcenter Amesim.

Example: Plot configuration files used to be able to handle multiple plot window instances. Due to the introduction of so called "tab widgets" in the Revision 9 Plot window, multiple instances of plot windows have been replaced by a single instance with multi-tab widgets.