> ------- Additional Comments from Andrew Miller <[EMAIL PROTECTED]> > Section 3.2.4 of CellML 1.1 states, in the second sentence of the second > paragraph: "Only one connection may be created between any given pair of > components in a model". > > This is a fairly pointless restriction from all fronts: > * From a model authors perspective, it creates a burden on the author to > consolidate all their connections which may have been created for different > purposes, and current model authors claim that such consolidation is time > consuming and error prone.
I'm not sure why this is the case. I much prefer to know that in any given model there is only one connection between two particular components and that is the *only* place I need to look to add, remove, or correct variable connections. If you allow multiple connections between the same components then it becomes much more difficult to locate extraneous connections, or perhaps software would simply use the first (or last) defined connection and leave an author bewildered when there model edits have no effect due to a missed connection element earlier. I'm really not sure who you mean by "current model authors"? But I consider such consolidation to be much less time consuming when editing complicated models and, as mentioned above, much less error prone. > * From a model readability perspective, it is also burdensome because > connections between variables may not be in a logical order (this is less of > an > issue if tools are used, but the point still holds). I'm not sure the specification should be designed to make the XML serialization look pretty - which is what you are saying here, right? If you want this to hold then you would need to add rules such that software is not allowed to change the order of the XML elements in a serialized document. > * Implementation experience suggests that it is no harder to allow multiple > connections between the same pair of components when writing simulation > software, but the extra constraint imposes more work on developers when > writing > tools which try to validate the model. This seems to be a good reason to keep the rule as it is. Given there is already a sever lack of CellML validation tools it seems a bad idea to be making it more difficult for people to write such tools. So, I guess what I'm saying is that I object to including this in CellML 1.2 - at the very least more discussion is needed to convince me this should be done at all. So far I'm seeing one strong reason not to change and no reason supporting the change... Andre. _______________________________________________ cellml-discussion mailing list cellml-discussion@cellml.org http://www.cellml.org/mailman/listinfo/cellml-discussion
