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Date: July 1, 2010
Time: 09:00 - 10:30 am
Venue: Skype Conference Call
Topic: Extendable version of OpenMI 2 (continued)

Table of contents

Participants

Rob Knapen, Alterra, Wageningen UR (Rob.Knapen@wur.nl)
Standa Vanecek, DHI (s.vanecek@dhi.cz)
Adrian Harper, Wallingford Software (adrian.harper@wallingfordsoftware.com)
Stef Hummel, Deltares (stef.hummel@deltares.nl)
~don, Deltares (gennadii.donchyts@deltares.nl)
~jgr@dhigroup.com, DHI (jgr@dhigroup.com)
Peter Schade, Bundesanstalt fuer Wasserbau (peter.schade(at)baw.de)

1. Progress towards OpenMI 2 Beta release

1.1. Source code update status - C#

• Update the IQuality interface

1.2. Documentation updates

(Peter) The current specifications define the ILinkableComponent, which is still time (Modified Julian Date) and space dependent.
Suggestion: Until 9. July mainly specify the IBaseLinkableComponent and a small general explanation of the Time+Space extension. The full Time+Space specification should follow after the sdk has been updated and tested.
(Stef) Maybe keep the documentation more or less as is, and only clearly describe the 'base' - 'timespace' leveling.
To be decided

2. Ongoing discussion topics

2.1. Note about OpenMI 2 compliancy

2.1.2. Two level compliancy

The compliancy with the OpenMI 2 standard is split into two levels. The OpenMI compliancy on the first level refers to basic interfaces whereas the OpenMI extension-compliancy includes additional interfaces, e.g. for time and space dependent components.

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Decision : We choose for the second description, including the rephasing of Jesper

2.1.3. What does the compliancy definition mean for the user?

(Peter)
"Linking OpenMI 2 compliant components has become much more flexible than it used to be with OpenMI 1.x. Components with different concepts or in OpenMI language extensions can exchange their data. A component with the classical Modified Julian Day time definition can for example provide a consumer component, defining its simulation time by an index, with data. The provider would implement the time and space extension whereas the consumer could implement an extension for index-related dictionaries. The provider should contain an AdaptedOutput converter using both time definitions and thus being able to convert the time to the index value. More knowledge about the underlying extensions is required from the user in order to select the appropriate items and to check the plausibility of the results. This is the price being paid for higher flexibility, less due to the OpenMI but to the complexity of the task.
If both LinkableComponents implement the same OpenMI extension interface, their provider consumer relationship will remain as straight forward as with OpenMI 1.x, the conversions in AdaptedOutput will be easier to use.

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Decision : we will move 4. to the assumptions underlying the OpenMI architecture.

2.1.4. What does the compliancy definition mean for an application developer?

todo, after 2.2. has been decided

3. New discussion topics

3.1. How to package and distribute extensions

(Rob) When an extension is approved by OATC will it be included into the Standard library (dll or jar), or will each extension be distributed in its own library?

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(Jesper) I believe (at least for C#, I am not sure with java) when we first have released the OpenMI2.Standard.dll, then there are issues in case this dll is updated to include e.g. a dictionary extension: Two different OpenMI2.Standard.dll files having the same version number, but different content. It would be much more safe to release an OpenMI2.Standard.DictionaryExtension.dll, and leaving the original content in the OpenMI.Standard.dll. It may be possible to put it all in a new standard dll, however that requires "intelligent" installers: Assume I am to install a TimeSpace engine and a Dictionary engine, which come with each their version of the OpenMI2.Standard.dll that they want to install and register in the GAC. Depending on the order in which I install the engines, each installer needs to know whether they are to reregister their version of the OpenMI2.Standard.dll in the GAC, to assure that the newest version is the one registered.

3.2. Events in the TimeSpaceExchangeItem

(Jesper) It was discussed in the last meeting to add extra events to the TimeSpaceExchange item to keep track of when the timeset and elementset changed. I would suggest to put these directly on the ITimeSet and ISpatialAxis/IElementSet instead. Especially, for the ISpatialAxis/IElementSet it could also be nice with a property bool IsDynamic, to indicate wether the ISpatialAxis/IElementSet can change at all.

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There is a number of discussions there, that has not yet been decided on.

3.4. Should an ITimeSpaceLinkableComponent override some of the IBaseLinkableComponent methods:

(Jesper) Currently an ITimeSpaceLinkableComponent provides its inputs and outputs as IBaseInput and IBaseOutput. Are these always transferable to ITimeSpaceInput and ITimeSpaceOutput, or could there be cases where other types of inputs and outputs are suitable? Would we even allow that? It could be considered to add methods to the ITimeSpaceLinkableComponent like:

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