For a few months, we have been working on spare-time on a in-house development, that may become a product one day. As it is fresh and cool, I can’t help giving some details about it.
Since we have a cross-platform product, we were starting to face a new problem: building and testing system models on each platform at each release. For example, we have a bunch of tutorials and demo cases we distribute with the software. Maintaining and testing all those tutorials is not only boring, but it takes hours to days : we definitely can’t afford it.
We also have some interesting engineering cases. While working on a big model for a customer on a given platform, we suspected that the solver was responsible for bad CPU performances. Someone asked me : “how does it run on other platforms ?”. Very good question, but i really didn’t have days to spend to reproduce the exact same system on the other platforms to answer this question, as interesting it was.
As a matter of fact, we needed some kind of Super Application Program Interface, to control all our simulation platforms in the same way: we could compare simulation results, and even maybe transform a model of a given platform to the others.
Most platforms provide some kind of API:
- SimulationX has a COM interface
- AMESim comes with VBA, matlab and python interface
- Matlab/Simulink provides command lines functions for all operations
As you may already know… I love python ! No way I would use anything else for such high level programming :
- COM is very nicely handled in the win32com library. SimulationX : checked
- AMESim has a python interface : checked
- Matlab… there must be something to deal with matlab ! My friend Google found this incredibly powerful library : matlabwrap. Matlab: checked
What we wanted is to have an object-oriented interface, common for all platforms, to deal with all basic operations :
- opening/saving/closing a model
- adding components and/or modifying the sketch
- modifying parameters
- getting simulation results
For sure, it has been a mess to code (as each platform’s API is very specific), and it is not completely tested yet. But the prototype is already very handy and quite powerful :
- we can access any component or variable of a model of any platform in a very clear and simple syntax
- parameters/results can be set/returned in standard python or numpy arrays format, for direct post-processing
- transforming a model from one platform to another is almost* automatic
(*) : almost… we didn’t get to transform platform specific models (for control, mechanics, etc…), we properly transform the ‘numenGo’ part of a system (retrieving position, orientation, parameters, connections, etc…). Most of the time, it covers 90-95% of the transformation work. The model is even stored in a neutral format corresponding to our metamodel.
As said above, it may never becomes a standard product, but we can use it on demand for clients who would like to share their models on different platforms.
Now, on this basis, our next move is to work out an automatic solution for cross platform testing : it implies to store some reference results, being able to compare them. So far, I am really considering pytables. Any better idea ?
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