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WSM Part 1

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And we will start right off with the first part which is the introduction to system modeling Here we will go through the most basic parts of system modeling, talk a bit about Wolfram SystemModeler and how it fits into all of this We will also talk a bit about what you need to get up and running with all this new functionality but most importantly in this part, we'll cover the most important thing, which is the system models, the actual models that we will be interacting with today We will be finding out how you can browse the built-in model repository in order to find models that you can simulate, that you can modify and analyze And also how you can import new models into your Wolfram Language session. So let's start with Wolfram SystemModeler, what is Wolfram SystemModeler? It is a stand-alone product from Wolfram Mathematica and other Wolfram Language Products, and it's a graphical user interface that allows you to create arbitrarily complex models from any number of different domains, including electrical, mechanical, thermal, biological models and so on. And I think I'll jump into SystemModeler a bit to show you how it looks so you can get a feeling for what a system model is. Now actually this first new command that I'm running from my Wolfram Mathematica notebook here, will actually not be available to Wolfram Language users those that don't have a copy of SystemModeler installed. And that is because it opens up SystemModeler itself, so that's pretty logical. So once I run this command, you'll notice that for you existing SystemModeler users, you'll notice that I didn't need to call the WSMLink package that you might be used to calling now. All of these functions are built into the Wolfram Language, they will just be there from the start. You can just type them into the session and the Wolfram Language will recognize it. No need to load any additional package or anything like that. So we call this SystemModeler function, it will open without any arguments, it will just open up a blank session of SystemModeler. And this is what it looks like, and what SystemModeler is, it's a tool that is flexible enough to build anything from a simple circuit, for example let's see if I can find a DC motor, there's some of them here. A simple electrical circuit like this one, this DC motor and you build models of different things in SystemModeler by dragging and dropping different components onto the canvas and then connecting them up together with the ports, in the case of an electrical circuit, you're connecting it kind of like… Yeah you're creating an electrical connection between the different components, and in the case of a mechanical system, like this inertia here, it's a mechanical system that's attached to the DC motor, then you're connecting things, like a solid mechanical connection. Now this is a very simple example of a model. We can scale this up to something which has for example thousands of different components we could look at the model of a car driveline instead and on the surface, this model built in SystemModeler might not look so complicated but in SystemModeler, in order to be able to build these highly detailed models without actually risking cluttering things up, you build things heirachily. You build them using like a normal whole, how things would look normally, where you, for example, could collect everything needed to model a transmission, you could collect that in one component, and then have smaller components that describe how this car transmission works. So you have a component that is the automatic control unit and you have one for the gear box and these can have even smaller components. So this is how the graphical user interface of SystemModeler allows you to create these arbitrarily complex models ranging from simple to very very advanced using just simple drag-and-drop methodology. And I forgot to mention but the components that you use here, they are all provided built-in to SystemModeler from many different domains, such as electrical, mechanical, thermal, biological and so on. However, today in this session we won't be as concerned with how these models are built, we will instead assume that you have a model that you want to analyze in some way, you might want to optimize this car driveline you might want to test how reliable this DC motor is to different types of scenarios. Then, we can use the Wolfram Language to try these different models in different scenarios. And that is what we will learn about today. So I'll switch back to my Wolfram Language session here and as I mentioned in the introduction, while it has previously been possible to connect SystemModeler with the Wolfram Language using a package previously called WSMLink, now we are fully integrating the simulation engine from SystemModeler, that is what allows you to actually take these models, analyze them, simulate them, visualize them and so on. And we are fully integrating it into Mathematica 11.3 And this means that we have a completely new system modeling interface, so this function here, it's completely new, and all the functions I will be showing today are brand new for 11.3 and they have expanded and streamlined capabilities compared to the old functions that were present in the WSMLink package. And as I also mentioned, this allows you to do a lot of these simulations and analysis of models without having a copy of SystemModeler, with just having a copy of the Wolfram Language, it allows you to send, if you are a model developer working in SystemModeler that would also allow you to send these models for any other Wolfram Language user to pick up, explore, analyze, visualize, and so on. But first I need to start with a bit of system requirements. Now in terms of systems that isn't a problem. Wolfram SystemModeler and Wolfram Mathematica, they both run on the same types of system. They include the simulation engine. It works for Windows, Mac OS, Linux, all the major platforms. So if you are able to run Mathematica, or any other Wolfram Language desktop product today, then you should be able to use this functionality, however one small caveat is that you need to install a compiler. And you might wonder why this is needed. And in order to take all these advanced system models, for example, take a model of a car which might have thousands of different components and then making it so that you can run these models very efficiently and simulate them very quickly then we translate those models, those equations, that form up those models. We translate that into highly optimized C++ code and then compile it into a standalone executable. And with this we want to ensure that even for very large systems, they can be simulated very quickly. So there's some built-in steps in order to configure a compiler for when those, there's even a built-in workflow where you can just click install and it should install the compiler. And once you've done that you can verify that you have a compiler hat SystemModeler recognizes up and running, and as we'll send out these notebooks I want to go through what each of these does, but there's a full list of instructions for installing these compilers are available in this presentation notebook that we sent out. Right, now if we want to simulate these models and we want to visualize them, how exactly do we find them? Now, SystemModeler comes with a wide range of pre-built models. I've shown you two right now, DC motor and a model of a car driveline. But I think there's hundreds, maybe thousands of other built-in simulation models that you can run just straight from your Wolfram Language session. And you can browse all of these with the new SystemModelExamples command. And this one provides, once it's loaded, provides you with an interactive interface where you can explore different packages in SystemModeler, or rather the SystemModeler engine that is included in the Wolfram Language. So even if you don't have SystemModeler, you can still call this SystemModelExamples function and find all the currently loaded run-able simulation models. And they are organized into different packages so we have some packages for different educational domains for example. So in electrical engineering we can find different run-able models, for example, a BoostConverter. And this will only look at the models that you can take and start to simulate directly. So that's one way of finding a model. Now if you already know what you're looking for, you can use the new SystemModel command and call a... with a string, ask for a model. And this might look a bit unconventional. It uses dots to separate these packages that I showed previously in the explorers. So if you have education examples, that's your top package, then “.ElectricalEngineering” so that's down one step in the package, and then another “.” and you'll find the model. So we can call this one and what we'll get back then is a SystemModel object. Now these are completely new in 11.3 and they provide you with different ways to interact with this model. You can think of it as a representation of a model that is loaded into SystemModeler. And we'll make use of these model representations pretty soon. Now if the name is unique, such as this BuckBoostConverter, you can just ask for “BuckBoostConverter” and then you'll get back exactly the same model. Now this also has autocomplete, so if for example, say you're looking for an engine, you can start typing in “Engine” and it would find different types of engine models that are currently loaded into SystemModeler. So here we'll get a V6 engine model that we can simulate and run. Now you might have more than one model that's called a certain thing, and if they exist in different packages this is perfectly allowed. But if you then try to use a short name to call the model, you'll get an error. But it will list all the available models that is called Rectifier. So we have some different types of rectifiers that we can get a model representation of. So say we want a multiphase rectifier, then we could call if by the complete name instead. And we'll get the model representation of that. So the models here that I've been showing, while you use drag-and-drop to create them, what is actually happening is that the graphical user interface is creating something that's called Modelica code or code that's written in the Modelica language. And this is a non-proprietary language that is used to describe different systems of equations. And it's pretty simple when you look at the most fundamental component for example. This is just a model of a simple differential equation. You just type down the equations and you can do this for yourself using the built-in text tool in SystemModeler, or you can create models using drag-and-drop and these equations and everything you need to accurately model your system will be created for you. But it's pretty nice actually, it's human-readable, so you can find out exactly what is happening inside the model And since it's completely text based you can get out a string from your model, which is pretty nice if you're doing revision control and so on. So, I only showed you now the models that are built into the SystemModeler engine, those that you will have access to, just as soon as you load up your Wolfram Language session, you will have access to those models. Now, since there's a lot of other sources for models that you can find. We publish a lot of downloadable examples on the SystemModeler webpage, the Wolfram Library Store provides you with different ways to extend the modeling capabilities of SystemModeler and also contains a lot of different run-able models. The Wolfram Community is a great source of models that you can import into your engine. And now, of course models that you create yourself either using the graphical user interface of Wolfram SystemModeler, or if you are creating models from the Wolfram Language, now that is also possible. And I will cover that later in this session. However, since the language is non-proprietary, there are also non-Wolfram sources that you can get models from, and the Modelica Association maintains a list of different model libraries that you can download and import into SystemModeler. And if you don't have SystemModeler, you can still import these models that you download from the web or so on. You just use the normal Import command in Wolfram Language and say that it's a model file, and Wolfram Language will recognize that and then load that model into your SystemModeler session. Now there's a new function in 11.3 which is pretty nice, which is called Iconize, and since these are SystemModels, they are just text based. You can pretty easily embed that text inside of a Wolfram Language notebook. And you can use the Iconize command to do this. So if I ask for the string of this SystemModel, I will get back that string in Wolfram Language representation, and I'll call Iconize to get back an iconized representation of that string. Now I can completely embed this in the model and for example have a function, at the beginning of my notebook that takes this string and imports it into the SystemModel engine session. So now I've imported this differential equation and I can find it in the browser I showed previously, or I can see if I switch to SystemModeler, I can see that it has been loaded. Now one thing I might not have made clear is that SystemModeler and the Wolfram Language these two sessions here, they are working on, they are using a shared state. Everything that happens in the Wolfram Language when I say to Import this, it will immediately be available in SystemModeler.

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Duration: 21 minutes and 11 seconds
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Language: English
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Posted by: wolfram on Jul 6, 2018

WSM Part 1

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