michaeltiller

7 ms·

1.
by michaeltiller 2y ago
Well if you are interested in the intersection of software engineering and technical computing, I'd recommend Julia. I'm currently working on JuliaSim which is a Modelica like system built on top of Julia. So Julia might interes
2.
by michaeltiller 2y ago
It is exclusive to JuliaSim. But the tools generate MTK compatible component models so, once built, they can be used with MTK.
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by michaeltiller 2y ago
It is pretty wide spread in automotive. I think nearly all F1 teams use it (hard to know for sure since they are quite secretive, but it is very common in my experience)
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by michaeltiller 2y ago
It means the causality is not built into the components but instead decided once your system is defined. The point is that you can make a change to the causality without having to refactor major parts of your model. It also means, even wi
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by michaeltiller 2y ago
Modelica by Example is the most recent and free, so I would recommend that.
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by michaeltiller 2y ago
JuliaSim does have graphical representation, a GUI and an IDE. But, granted, it is also a commercial product, not open source.
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by michaeltiller 2y ago
Well most Modelica tools generate C code. I think all of them also generate FMUs (lookup Functional Mockup Interface, if you don't know what an FMU is). Some FMUs are source code FMUs (suitable for running on HiL hardware, for exampl
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by michaeltiller 2y ago
Just to be clear, there is absolutely nothing "corporate" about that web site. It is a non-profit organization.
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by michaeltiller 2y ago
Yes. And "Introduction to Physical Modeling with Modelica". I also built the Modelica Playground (which I deliberately didn't link to because a thundering herd of HN readers would have crashed it).
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by michaeltiller 2y ago
The Modelica Association is a non-profit that publishes the specification, the standard library and all conference proceedings for free. We sell merch in part because people in the Modelica community like the language and like to show it b
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by michaeltiller 2y ago
Modelica is nearly 30 years old, BTW.
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by michaeltiller 2y ago
OK, those are three quite different things. Modelica allows you to create models in a similar way to spice by describing components and how they are connected. But instead of a netlist of nodes, Modelica has a concept of connectors. But o
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by michaeltiller 2y ago
Modelica not only has discrete events (see other comment), it includes support for synchronous (clocked) systems of equations directly in the language. These kinds of language semantics are necessary if you want to have unambiguous discret
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by michaeltiller 2y ago
Over 20 years ago I modeled an internal combustion engine, an automatic transmission and a multibody chassis model all in a single model. IIRC, the model had something like 250,000 equations in it and it modeled combustion, hydraulics, fri
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by michaeltiller 2y ago
Modelica by Example is a textbook on Modelica, not a searchable index of models. It doesn't even cover the Modelica Standard Library in any details much less the many other Modelica libraries out there. To determine if something has
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by michaeltiller 2y ago
I actually would disagree that Bond Graphs are the "underlying mechanism" in Modelica. The Modelica community and the Bond Graph community are a bit at odds in fact. My side of this story can be found at [1] and [2]. I disagree
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by michaeltiller 6y ago
That's an interesting way of framing it. I tend to agree. It isn't so much the presence of the type system so much as the fact that the compiler is given sufficient information (much of it symbolic) to aggressively optimize the
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by michaeltiller 6y ago
Chris, I agree that the symbolic processing is quite important. I've often made the argument that a purely numerical approach just can't compete because of the optimizations and insights that come out of the symbolic analysis wil
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by michaeltiller 6y ago
FYI, it is by the same people who initiated the Modelica effort (Hilding Elmqvist and Martin Otter). I think part of the goal was to shed having to maintain a whole language (and the need to specify all the semantics details of such) and s
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by michaeltiller 6y ago
But, of course, what is solvable changes and/or is implementation dependent. Modelica doesn't say much on the topic of impulses. In theory, a vendor could support variable index systems along with the ability to resolve impulses
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by michaeltiller 6y ago
Very true. But I think it is important to understand the alternative. The "object-oriented" part of Modelica is intended to make creating large scale models manageable. You make it sound like the object-oriented features are som